Case histories and weather data are presented for four pavement sections constructed during different seasons with the same concrete mixture possessing the same properties obtained from the same ready-mixed concrete supplier.  Photographs were taken of areas of the pavements at different stages of scaling, and petrographic core examinations were made.  Area 80 constituted well-air-entrained concrete, but the topmost section of the pavement was susceptible to disruption by freezing and thawing because of high absorptivity resulting from lack of adequate curing and early drying and carbonation of the cement paste matrix.  The action of freezing was aggravated by the presence of deicing salts.  Areas 92, 93, and 98 comprised non-air-entrained concrete that was not resistant to freezing and thawing, especially in the presence of deicing salts.   Sections constructed with low water–cement ratio concrete were susceptible to rapid disintegration during repeated freezing.  Incipient cement–aggregate reactions involving dolomites, chalcedonic cherts, and cherty phases of dolomites occurred, but no deleterious effects were indicated by the petrographic examination.   These tests indicate that air entrainment will not ensure adequate durability of exposed concrete in the absence of good concreting practices.  The defect leading to failure of the concrete in area 80 was the result of inattention to curing and protection of the concrete from early drying.  The defect leading to failure of the pavement surfaces in the other areas was the absence of a proper entrained air void system in the concrete.

Adkins, D.F., and V.T. Christiansen, "Freeze-Thaw Deterioration of Concrete Pavements," Journal of Materials in Civil Engineering, 1(2): 97-104.

This discussion of how concrete freezes and thaws under natural conditions focuses on the thermal and hydraulic stresses involved in surface scaling.  The mechanics of surface scaling are described, and freezing within the paste is discussed, as are temperature and saturation differentials.  A series of laboratory and field tests were conducted to establish the validity of the theory that surface scaling could result from freezing temperatures converging upon a zone of greater saturation.  Conclusions drawn from the study are presented and discussed.

Al-Omari, B., and M.I. Darter, Relationships Between IRI and PSR, Interim Report, Publication No. UILU-ENG-92-2013, Illinois Department of Transportation, September 1992, 71 pp.

This report documents the work accomplished on a study to develop relationships between the International Roughness Index (IRI) and the Present Serviceability Rating (PSR) for pavement types included in the Highway Performance Monitoring System (HPMS) database (flexible, rigid, and composite pavement types).  PSR is defined as the mean user panel rating for rideability.

Relationships between IRI and PSR were analyzed for Louisiana, Michigan, New Jersey, New Mexico, Ohio, and Indiana.  Data for all six States were analyzed using a statistical software package, and the following nonlinear model was developed:

PSR  =  5 * e ^{(a * IRI)}            (52)

Regression analysis was conducted for all possible sets of data considering different States and pavement types.  It was determined that there was no significant difference between the models for different States or pavement types; therefore, the following model is recommended:

PSR  =  5 * e ^{(-0.0041 * IRI)}             (53)

where IRI is in units of in/mi, or:

PSR  =  5 * e ^{(-0.26 * IRI)}            (54)

where IRI is in units of mm/m.

Al-Suleiman, T.I., K.C. Sinha, and V.L. Anderson, "Effect of Routine Maintenance on Pavement Roughness," Transportation Research Record 1205, Transportation Research Board, 1988, pp. 20-28.

This paper presents a study of the relationship between routine maintenance expenditure level and pavement roughness.  A database by contract section was developed for the State highway system of Indiana.  Covariance analysis was performed to test the effect of climatic region.  Regression models were developed to examine the effect of routine maintenance expenditure level on rate of change in pavement roughness.  Two highway classes and three pavement types were considered in the analysis.  The database included a total of 550 pavement contract sections.  The results can be used to develop an effective maintenance program.

American Association of State Highway and Transportation Officials, Implementation Manual for Quality Assurance, AASHTO Highway Subcommittee on Construction, 1996, 92 pp.

This manual presents important considerations for developing and implementing a quality assurance program within a highway agency.  Topics discussed include management and industry support, program goals, an implementation plan, and general principles for developing specifications.

American Association of State Highway and Transportation Officials, Quality Assurance Guide Specification, AASHTO Highway Subcommittee on Construction, 1996, 46 pp.

This document is a companion to the Implementation Manual for Quality Assurance.   It contains procedures and requirements for sampling and testing, validation, construction requirements, quality control, and acceptance of newly constructed pavements.

American Association of State Highway and Transportation Officials, Standard Recommended Practice for Acceptance Sampling Plans for Highway Construction, AASHTO Designation: R 9-90.

This recommended practice provides guidance in the preparation of statistical acceptance plans for transportation materials and construction items.  The procedures outlined are based on percent defective (or percent within limits) as the quality parameter.  The various discussions, tables, and examples in this guideline assume that the acceptance procedures will be used to accept or reject the work.  Although it is logical to extend this methodology to the development of acceptance procedures with adjusted pay schedules, that application is not addressed in this guideline.

American Concrete Institute, Guide for Construction of Concrete Pavements and Concrete Bases, Publication No. ACI 325.9R-91, December 1991, 27 pp.

This report is intended as a guide for the construction of concrete pavements and concrete bases.  References are made to specifications, but only as a guide to enable a selection of requirements suitable for a particular location or class of work.  The intended users of this guide are agencies other than State highway departments or turnpike and airfield authorities.  The report covers topics such as sampling and testing of materials for quality assurance; subgrade or subbase preparation and forms; installation of joints and reinforcement; high-early-strength concrete; mixing, placing, finishing, and curing concrete; and cold and hot weather concreting.

American Concrete Institute Committee 214, Guide for Obtaining Cores and Interpreting Compressive Strength Results, May 1995, 44 pp.

Core testing is the most direct method for determining the compressive strength of concrete in a structure.  Generally, cores are obtained to assess whether suspect concrete in a new structure complies with strength-based acceptance criteria, or to evaluate the structural capacity of an older structure based on the in-place concrete strength.  In either case, the process of obtaining core specimens and interpreting the strength test results is often confounded by various factors that affect either the in-place strength of the concrete or the observed strength of the test specimen.  The scatter in strength test data, which is inevitable given the inherent randomness of in-place concrete strengths and the additional uncertainty attributable to the preparation and testing of the specimen, may further complicate compliance and evaluation decisions.

This guide summarizes current practices for obtaining cores and interpreting concrete strength test results.  Factors that affect the in-place concrete strength are reviewed so that locations for sampling can be selected that are consistent with the objectives of the investigation.  Strength correction factors, which account for the size and condition of the core test specimen, permit the strengths observed on non-standard specimens to be converted to the strength of equivalent standard specimens.   Methods for checking strength compliance of concrete in new and old structures are summarized.

American Concrete Institute Committee 325, Accelerated Concrete Paving Techniques, Draft Report, October 1995, 59 pp.

This report covers the state of the art of accelerated concrete paving techniques, often referred to as "fast-track" concrete paving.  Accelerated concrete paving techniques are appropriate for roadways, airfields, and other paved surfaces where quick access is required.  Accelerated concrete paving considerations include planning, concrete materials and properties, jointing and joint sealing, curing and temperature control, concrete strength testing, and opening-to-traffic criteria.   Applications and uses of accelerated concrete paving are discussed.

Amsler, D.E., and J.E. Bryden, Effects of the Clary Screed and Tube Float on Rigid Pavement Construction, Publication No. NYSDOT-ERD-75-RR-32, New York State Department of Transportation, August 1975, 24 pp.

Effects of the Clary screed and the tube float (used as finishing devices on portland cement concrete pavement placed with a slipform paver) were examined on six construction projects.  Alternate sections were finished with and without the Clary screed on three projects.  Sections making up the remaining three projects were finished with different numbers of passes (0, 2, 4, or 6) with a tube float.  Pavement roughness was measured with a California profilograph, and surface mortar samples were tested for compressive strength.  The screed (used without additional water) resulted in a reduction of roughness and was not considered detrimental to the surface mortar.  The tube float (normally used with a fog-spray of water) had little effect on roughness and resulted in a substantial reduction in the compressive strength of the surface mortar.

Anderson, S.M., and R.L. Carrasquillo, The Effects of Withholding Mixing Water and Retempering on Properties of Concrete, Interim Report, Publication No. FHWA/TX-88+1117-1, Texas State Department of Highways & Public Transportation, February 1988, 128 pp.

An experimental program examined the effects of withholding mixing water at initial batching (followed by retempering of the mix at the job site) on the properties of the concrete produced for highway applications.  Additionally, the effects of redosage with more water than that specified in the mix design were examined.  Tests were performed to determine the effects on slump, air content, unit weight, compressive strength, flexural strength, abrasion resistance, and freeze-thaw resistance.  The effects of varying the withholding amount, withholding time, and cement content on the fresh and hardened concrete properties mentioned above were examined.  The concrete examined was produced at a ready-mix concrete facility to duplicate (as closely as possible) job site conditions arising in typical concrete construction.  The results of the study show that significant detrimental effects occur when mixing water is withheld and concrete is retempered at a later time.  Slump, air content, abrasion resistance, and freeze-thaw resistance are all adversely affected.  The effects were found to vary with variations in both withholding time and cement content.  The strength was not affected when water was withheld and concrete was retempered, but a reduction in strength accompanied an increase in water-cement ratio above design values at redosage.   The changed properties lead to concrete with reduced quality and questionable performance.

Ansari, F., "In-Place Air Content of Concrete by Fiber Optics," Strategic Highway Research Program Products: Proceedings of a Specialty Conference Sponsored by the Highway Division of the American Society of Civil Engineers and the Federal Highway Administration, April 1991, pp. 41-43.

A new fiber-optic apparatus to determine the air content of freshly mixed-in-place concrete is described.  Such a device may eventually be used to facilitate acceptance or rejection in the field.  The results of this research included the following:

• A methodology for the rapid and nondestructive monitoring of concrete air void content during mixing, transporting, and placement.

• Development of a hand-held portable device based on the developed methodology.

• Laboratory and field experimentation of the new device, as well as a comparison of results with conventional testing methods.

Ardani, A., PCCP Texturing Methods, Interim Report, Publication No. CDOT-DTD-R-95-2, Colorado Department of Transportation, February 1995.

This report describes the testing and construction details of nine test sections with varying textural characteristics.  The impacts of various surface textures (sawed versus tined, longitudinal versus transverse, and random versus uniform spacing) on the frictional and noise characteristics of pavement surface were examined.  Skid numbers were acquired at different combinations of tire type (ribbed and smooth) and speed (64.4, 80.5, and 104.6 km/h) for all the test sections.  Six different types of texture measuring devices were used to compare the amount of texture in each test section.   To examine the noise properties of the test sections, noise data were acquired in three different locations: (1) inside the test vehicle, (2) 7.62 m from the center line, and (3) near the right rear tire of the test vehicle (away from the exhaust pipe).

Armstrong, J.P., "Accelerated Strength Tests for Quality Control of Concrete Pavements," Proceedings: Fourth International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, Publication No. FHWA-RD-89-208, April 1989, pp. 519-530.

This paper presents the results of a laboratory-based effort to evaluate potential methods of obtaining flexural strength for pavement quality control using accelerated test methods (within 24 h).  Current U.S. Army Corps of Engineers pavement design procedures specify 28- and 90-day flexural strengths for roads and airfields, respectively.  Quality control of pavement concrete strengths use correlated 7- and 14-day flexural strengths to identify problems as early as possible; however, compliance with specifications still depends on the 28- and 90-day strengths.  These lengthy test times are not adequate to identify pavement strength problems, particularly with today's rapid construction techniques.  A literature review indicates that accelerated test methods employing elevated curing temperatures are available for evaluating compressive strength (ASTM C 684), but comparable procedures for the more sensitive flexural strength have not been published or accepted.  Some success has been achieved in predicting long-term flexural strength using the boiling method (ASTM C 684, Procedure B).  More recent work indicates that a warm water curing method (ASTM C 684, Procedure A) is safer, may be more reliable, and causes fewer deleterious effects to the specimen; therefore, it was pursued in this study.

To determine the most effective 1-day measure of concrete quality, accelerated (24 h in an elevated temperature water bath) and 14-day flexural, splitting tensile, and compressive strengths were compared to 28- and 90-day flexural strengths.  Three concrete mixtures were prepared by varying water-cement ratios to provide a wide strength range.  Ten batches of each mixture were cast into beams and cylinders (a total of 1,061 specimens) for testing.  Based on the coefficient of determination (R²) for regression equations, the warm water method (R² = 0.894 to 0.945) provides reliability equal to, if not greater than, the 14-day tests (R² = 0.785 to 0.920) in predicting 28- and 90-day flexural strength.

Ayton, G., J. Cruickshank, E. Haber, and H. Richard, Concrete Pavement Manual: Design and Construction, Edition 2, Revision 3, New South Wales Roads and Traffic Authority, 1994.

This manual documents the Australian experience with concrete pavement construction.   It discusses factors that are both external (e.g., traffic, climate) and internal (e.g., thickness, construction quality) to the pavement in order to demonstrate the importance of construction standards and structural detailing on the performance of concrete pavements.  According to the authors, construction standards and structural detailing account for all but a few of the premature failures in pavements constructed in New South Wales in the past 15 years.

Bartlett, F.M., and J.G. MacGregor, "Equivalent Specified Concrete Strength From Core Test Data," Concrete International, March 1995, pp. 52-59.

The purpose of this paper is to present a simple procedure for determining a value of concrete strength from core strength data to be used for structural evaluation.  In practice, the number of cores obtained for testing is usually limited by budgetary constraints and, in some cases, by concern about unduly weakening the structure.  It is convenient for the resulting strength value to be equivalent in definition to the specified strength of concrete, f¢_c.

Bock, B.T., and P.A. Okamoto, "Evaluation of Dowel Placement Using a Dowel Bar Inserter," Proceedings: Fourth International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, Publication No. FHWA-RD-89-208, April 1989, pp. 641-649.

This paper presents the results of several field investigations to evaluate the effectiveness of automatic dowel bar inserter equipment.  The results summarize three studies in which ground-penetrating radar (GPR) was used to measure dowel bar misalignment.  The studies used a commercially available radar system capable of locating steel embedded in concrete.  The system produces a real-time graphic recording that indicates the horizontal position and relative depth of the embedded steel.   Cores were obtained to calibrate the graphic recordings by obtaining the actual embedded depth of the steel bars.  In two of the three studies, GPR was used to measure the alignment of dowel bars placed using Guntert and Zimmerman dowel bar inserters, as well as those placed on wire basket assemblies.  Overall, the dowel bar inserters performed well compared to the basket assemblies.  Dowel depth, misalignment (vertical and horizontal), and longitudinal displacement are generally comparable.

Burati, J.L., Jr., M.G. Beeson, and H.S. Hill, Jr., "Comparative Analysis of Dowel Placement in Portland-Cement Concrete Pavements," Transportation Research Record 924, Transportation Research Board, 1983, pp. 19-27.

No statistically valid proof has been found to indicate that dowel bar alignment is better or worse when the basket assembly or implanted dowel placement method is used.   Also, no significant difference has been identified in the amount of joint-related distress caused by the two methods.  There is no evidence that the joint-related distress on the projects studied can be directly linked with the type of dowel misalignment studied, because alignment error does not appear to be the sole determining factor of the distress.  Statistical tests and comparison procedures were employed to analyze collected alignment data, and attempts were made to relate the alignment results to distress data.  Conclusions were drawn indicating that neither placement method appears to be superior, but statistical proof could not be established.  Many uncontrollable variables, such as work crew difference, equipment difference, and inspection, may be as important to dowel alignment as the examined variables.   Alignment data regarding dowel depth were unobtainable due to the electronic detection method of data collection employed and a prohibition against coring.   Further research should address this limitation.

Burg, G.R.U., "Slump Loss, Air Loss, and Field Performance of Concrete," American Concrete Institute Journal, 80(4): 332-339.

Field and laboratory experience demonstrates that when concrete loses slump, there is generally a loss of entrained air content.  Results obtained from tests made in conjunction with a large concrete roadway and parking lot paving project may give the answer to the often-asked question, "Is slump loss due to the loss of air, or is air loss due to the loss of slump?"  The purpose of these tests was to study the following:

• The accuracy of current recommendations for durable concrete pavement.

• The history of air-entrained pavement-type concrete as it matures from the time it was freshly mixed to after it has been in service for several years.

• The degree of confidence that can be expected when using standard ASTM test methods to obtain certain selected concrete qualities.

Tests were made on randomly selected truckloads of freshly mixed concrete at three different times: at the central mix plant (as mixed), at the job site (as received), and at the job site (as retempered).

Chamberlin, W.P., Performance-Related Specifications for Highway Construction and Rehabilitation, Synthesis of Highway Practice 212, National Cooperative Highway Research Program, 1995, 48 pp.

The objectives of this synthesis are to identify current use of PRS by highway agencies and to describe the development and present status of PRS for highway materials and construction.

With the exception of the New Jersey Department of Transportation’s specifications for portland cement concrete (PCC) strength and its experimental specifications for PCC pavement, no examples or operational PRS that conform to the definition adopted for this study were identified among highway agencies.  Further, it was concluded from questionnaire responses that although the concepts of PRS are well-understood within the research community, they have not been communicated effectively to the highway construction community at large.

Continuation of PRS development at the national level and parallel efforts at local levels are recommended to increase awareness of PRS concepts and encourage the development of experimental specifications.  Immediate preparation of educational and instructional materials on current and planned adjustable payment acceptance plans and their operating characteristics is also recommended as a means of addressing the issue of their fairness to both owners and contractors.

Cole, L.W., and P.A. Okamoto, "Flexural Strength Criteria for Opening Concrete Roadways to Traffic," Transportation Research Record 1478, Transportation Research Board, 1995, pp. 53-61.

Various criteria have been used for opening concrete roadways to traffic.  Most criteria are based on the accumulated judgment of specifying agencies or other authorities.  Little or no engineering analysis exists to substantiate most opening-to-traffic criteria currently in use.  On the basis of Miner’s hypothesis of accumulated fatigue, flexural strength opening criteria are presented for concrete roadways (municipal and highway) subjected to construction and public traffic.   The criteria are appropriate for new construction, reconstruction, and concrete overlays except bonded concrete overlays.

Concrete Pavement Construction - Inspection at the Paving Site, Publication No. EB085.01P, Portland Cement Association, 1980, 19 pp.

Methods for producing high-quality, durable, smooth-riding concrete pavements are described, and the responsibilities and duties of the inspector at the paving site are outlined.  Tips for good inspection at the paving site are presented.

"Concrete Pavement Joints: Should They Be Warranteed?" Better Roads, 53(8): 26-28.

Because most concrete pavement failures are joint-related, many design engineers, public works agencies, and governmental agencies would welcome joints warranteed for several years with free replacement of failures.  A few engineering departments now get such warranties for up to 10 years.  Implementation of a warranteed contract that avoids joint problems requires cooperation between design engineer, contractor, and materials supplier.  This article discusses the various factors and requirements involved.

"Construction Practices and Inspection Pavements. Recommendations for Construction of Concrete Pavements and Concrete Bases," ACI Manual of Concrete Practice 1990. Part 2., Publication No. ACI 316R-82, American Concrete Institute, 1990, 26 pp.

This recommended practice covers construction of concrete pavements and concrete bases without attempting to include inflexible specifications for procedures, materials, or equipment.  References are made to specifications, but only as a guide to enable a selection of requirements suitable for a particular location or class of work.  The document is slanted to some degree toward use by agencies other than State highway departments or turnpike authorities, which have presumably large and experienced engineering staffs.  Sections are devoted to specifying, sampling, and testing materials, and to the possible influence of materials on skid resistance, economy, and durability.  Subgrades and subbases are treated only as a final preparation for paving.  Recommendations for forms are included, as are recommendations for projects using slipforms.  Arrangement of joints is described, and references are given for guidance in using reinforcement.  Sections on normal and high-early-strength concrete proportioning rely heavily on reference to the report of ACI Committee 211, but point out the special problems connected with pavement concretes and the use of admixtures.

Cumbaa, S.L., "Correlation of Profile-Based and Response-Type Roughness Devices for Louisiana's Highway Performance Monitoring System," Transportation Research Record 1260, Transportation Research Board, 1990, pp. 99-105.

Relationships were developed to meet and facilitate roughness reporting and calibration requirements of the Highway Performance Monitoring System (HPMS) in Louisiana.   Pavement roughness statistics obtained from a Face Dipstick, K. J. Law Model 8300 Roughness Surveyor, and Mays Ride Meter were correlated to enable Louisiana to satisfy these requirements.  On the basis of the results of this research and previously established relationships between the Mays Ride Meter and the AASHO serviceability index (SI), the international roughness index (IRI) and SI were compared for flexible and rigid pavements.  A correlation was established between the IRI values obtained with the Face Dipstick and those obtained with the Model 8300 Roughness Surveyor for five flexible and four rigid pavement test sections.  Correlations from field testing of the Model 8300 Roughness Surveyor and Mays Ride Meter on 20 flexible and 19 rigid test sections resulted in a distinct relational equation for each pavement type.  However, results relating IRI and SI indicated that this relationship was the same for all pavement types.

"Curing of Concrete Pavements," Transportation Research Circular, Issue 208, Transportation Research Board, June 1979, 11 pp.

The Current Road Problem Series was developed by the Highway Research Board during World War II as a series of emergency pamphlets.  The Committee on Curing of Concrete Pavements prepared one such pamphlet, first published in 1942 as Wartime Road Problems No. 1, which contained the then-current recommended practices for curing concrete pavements.  It was revised in October 1952 as Current Road Problems No. 1-R, Curing of Concrete Pavements, which also contained suggested specifications and test methods.  It was again revised and updated in May 1963 and titled Current Road Problems No. 1-2R, Curing of Concrete Pavements.  The current publication updates the recommended practices and specifications of the 1963 edition.

Darter, M.I., "Variations of Concrete Properties Related to Rigid Pavement Design and Performance," Term Report for CE 393, University of Illinois, 1972.

The purpose of this paper was to summarize the types and causes of variations of concrete properties, to obtain an estimate of their probability frequency distribution and expected standard deviations, and to discuss the design and specification implications.   Since concrete properties such as modulus of elasticity and strength have a significant effect on concrete pavement performance, any variability in these factors will affect the performance of the pavement.  A probabilistic design approach (as opposed to a deterministic approach) makes it possible to consider the means and relative variations of design factors in the design process.  To use a probabilistic approach, the designer must know the type, distributions, and magnitudes of these uncertainties.   This paper attempts to relate the types and causes of concrete pavement variations to aggregates, paste, proportioning, construction, and environment.  Measured variations were reported for compressive, flexural, and tensile strength; modulus of elasticity; fatigue; joint load transfer; serviceability index; and slab thickness.   The normal magnitude of these variations was found to have a considerable effect on pavement performance, and the variations should be considered quantitatively in pavement design.

Darter, M.I., K.D. Smith, and D.G. Peshkin, "Field-Calibrated Mechanistic-Empirical Models for Jointed Concrete Pavements," Transportation Research Record 1307, Transportation Research Board, 1991, pp. 143-153.

Field-calibrated mechanistic-empirical models have been developed for key performance indicators of jointed concrete pavements.  Performance data from nearly 500 in-service pavements were used along with mechanistic and empirical variables to develop improved prediction models for joint faulting, slab cracking, joint spalling, and present serviceability rating.  The models should prove extremely valuable in checking the performance capabilities of various pavement designs determined by other means and in determining the relative impact of different design variables on concrete pavement performance.  However, the models must be used with care and applied judiciously because it is imperative that they not be extended beyond the conditions for which they were developed.

Darter, M.I., M. Abdelrahman, P.A. Okamoto, and K.D. Smith, Performance-Related Specifications for Concrete Pavements, Volume I: Development of a Prototype Performance-Related Specification, Publication No. FHWA-RD-93-042, Federal Highway Administration, November 1993, 219 pp.

This study continued the development of performance-related specifications for concrete pavements.  Drawing upon previous work, a prototype PRS was developed that considers the expected life-cycle cost of the as-constructed pavement as the overall measure of quality.  The approach calls for measurement of in situ concrete properties and explicitly considers variability and multiple quality characteristics in the determination of pay adjustments.  Extensive laboratory testing was conducted to determine material relationships needed in the prototype PRS, and a detailed test plan was developed for the evaluation of construction variables that significantly affect concrete pavement performance, but are not currently accounted for in the specification.  A computer program, PaveSpec, was developed for use with the specification in simulation and in generating pay adjustments.

This volume describes the development of the prototype PRS.  Concrete strength, slab thickness, entrained air content, and initial smoothness are included in the specification as the key quality characteristics.  Both cost models and distress prediction models are used to compute life-cycle costs.  The difference between the life-cycle costs of the target, as-designed pavement and the actual, as-constructed pavement is used to determine the pay adjustment.  Numerous examples on the use and sensitivity of the specification are presented.  A summary of the laboratory testing results that were used in the specification is given, along with a test plan, for the evaluation of quality characteristics not currently included in the specification.

Darter, M.I., M. Abdelrahman, T. Hoerner, M. Phillips, K.D. Smith, and P.A. Okamoto, Performance-Related Specifications for Concrete Pavements, Volume II: Appendix A—Prototype Performance-Related Specification, Appendix B—PaveSpec Users Guide, and Appendix C—Annotated Bibliography, Publication No. FHWA-RD-93-043, Federal Highway Administration, November 1993, 177 pp.

This volume includes supporting documentation for the research study.  The prototype PRS is included in its entirety in appendix A.  This specification is complete for pilot testing, verification, and validation on simulated and actual construction projects.  Appendix B contains a users guide for the PaveSpec computer program, and appendix C presents an annotated bibliography of literature pertinent to construction specifications.

Demos, M., N.G. Gharaibeh, and M.I. Darter, Evaluation of Potential Applications of End-Result and Performance-Related Specifications, White Paper Presentations—Part II, Chapter V—Portland Cement Concrete Pavements, Publication No. FHWA-IL-UI-256, Illinois Department of Transportation, December 1995, 85 pp.

The primary objective of this study is to evaluate, based on the best available technology, the potential applications of end-result specifications (ERS) and performance-related specifications (PRS) to asphalt concrete paving, portland cement concrete paving, and structural concrete construction.  For each area, the following tasks were performed:

• Review of current literature on ERS and PRS.
• Comprehensive evaluation of other State practices to include parameters used, lot size, and payment schedules.
• Review and evaluation of current Illinois DOT specifications, practices, and policies.
• Identification of relevant IDOT data that have potential application.
• Evaluation of the feasibility of relating materials and construction data to facility performance.
• Determination of the quality of available data and their appropriateness for data analysis.
• Statistical analysis of selected variables within available data and determination of their suitability for developing ERS and PRS.

The study is organized into two parts. Part I discusses the basic concepts and the development of ERS and PRS, and quality acceptance plans.  Part II discusses the framework of ERS and PRS, current practice, and data analyses for each of the three areas studied.  The report also contains a literature review, summary of other State practices, review and evaluation of the IDOT specification, analyses of MISTIC data, potential linking of MISTIC and Illinois Pavement Feedback System data, and recommendations for improvements to current QC/QA specifications for structural concrete construction.

Dempsey, B.J., W.A. Herlache, and A.J. Patel, The Climatic-Materials-Structural Pavement Analysis Program, User’s Manual, Publication No. FHWA-RD-84-115, Federal Highway Administration, February 1985, 208 pp.

This publication is the User’s Manual for the Climatic-Materials-Structural Pavement Analysis Program (CMS program), which is described in detail in the report entitled Volume 3. Environmental Effects on Pavements—Theory Manual (FHWA-RD-84-115).

The CMS program is a climatic model used to analyze multi-layered flexible pavement systems.  It simulates field conditions by accounting for the fact that climatic characteristics (e.g., minimum and maximum air temperature, sunshine, wind velocity, precipitation) vary with geographical location in many States.  The climatic model incorporated in the CMS program takes climatic and material inputs and calculates temperature and moisture profiles as they vary with time.  This information is then used in the material model to calculate the asphalt, base, subbase, and subgrade stiffness characteristics.  This output can then be combined with load data and input into various structural analysis and performance models. It is believed that this type of analysis will give a more reliable indication of pavement performance than will a model that ignores the effects of climate.

"Development of Pavement Performance Measures in the Contract Equation," Summary of Workshop Proceedings, Transportation Research Board, Washington, DC, December 1995.

The purpose of this workshop was to identify items in the construction contract for which specifications to encourage improved pavement performance may be applicable; to develop a consensus on useful measures of performance; and to set out research needs in measuring performance.  The workshop brought together a wide range of individuals from throughout the United States to discuss the current status of performance measures and to help chart a course to advance the state of the practice.  The main products of the workshop were the action plans for advancing pavement performance measures and their use as tools in achieving quality, encouraging innovation, and improving efficiency in highway construction programs.

Devore, J.J. and M. Hossain, An Automated System for Determination of Pavement Profile Index and Location of Bumps for Grinding From the Profilograph Traces, Publication No. K-TRAN: KSU-93-2, The Kansas State University, May 1994, 83 pp.

The objective of this research was to develop an automated system to reduce traces generated by a manual profilograph.  The tasks included locating and marking the bumps that would require grinding and determining the profile index of the new riding surface.  The objective was accomplished following the guidelines provided in Kansas Test Method KT-46I. This research resulted in a compact and easy-to-use system capable of reducing any profilogram.  The program allows the operator to select values for parameters such as bump template height and blanking band width to conform to existing specifications.  The KSCAN version uses a hand-held scanner and straight edge guide and is designed to reduce single sections of trace 0.16 km ± 76.2 m in length.  The PROSCAN version uses a motorized paper feed and will automatically reduce traces of any length, giving results in 0.16-km sections.

Dhir, R.K., P.C. Hewlett, E.A. Byars, and J.P. Bai, "Estimating the Durability of Concrete in Structures," Concrete, 28(6): 25-30.

This article discusses the results of an investigation into the assessment of concrete durability.  Conclusions of the research include the following:

• The established methods of measuring permeation properties of concrete (absorption, permeability, and vapor diffusion) relate well to one another.

• Concrete durability can be classified in terms of initial surface absorption, but allowance must be made for the binder type when the aspect of durability considered is other than purely physical, such as for chloride diffusion or carbonation.

• Concrete durability can be predicted from mix constituents and their preparation, duration, temperature of moist curing, and initial surface absorption. This gives an opportunity to build further confidence in durability predictions.

• Existing preconditioning techniques for permeation testing are unsuitable for in situ compliance testing.  A method of standardizing the moisture content of concrete using a hard vacuum has been developed, applicable over a range of initial moisture contents from dry (28 days air curing) to saturated (28 days water curing).

• Vacuum equipment for preconditioning the moisture content of concrete has been developed as a permeability index test (VPIT) in its own right.  The test is nondestructive, is attached by vacuum alone, and is sensitive to the same parameters as other permeation tests.

Di Cocco, J.B., Quality Assurance for Portland Cement Concrete, Publication No. FHWA-RD-73-077, Federal Highway Administration, September 1973, 157 pp.

Quality assurance has been used successfully in most industries, but the construction industry and State agencies are only now beginning to recognize its importance.  The work reported here results from this recognition and is one attempt to show how the elements of quality assurance can be applied to concrete.  Chapter I deals with concrete uniformity and compliance with specifications requirements.  Under the current degree of process control and inspection, both uniformity and compliance are found to be poor.  Chapter II deals with techniques that producers should use to achieve compliance with concrete requirements and includes three case studies to show that process control does indeed lead to compliance.  It is also stressed that process control is the responsibility of producers, but recognizing that inspecting agencies (having done most of the testing in the past) may have more pertinent information than producers, guidelines are suggested for producers to use until they accumulate data of their own.

The next four chapters deal with acceptance sampling (inspection).  Chapter III discusses the basic concepts of acceptance sampling. In chapter IV, current inspection schemes are reviewed, with particular attention to those used in New York.  It is concluded that these schemes afford little protection to concrete buyers, and statistically sound sampling plans are suggested for inspection of fresh and hardened concrete.  The advantages and shortcomings of the suggested plans are discussed in chapter V, along with the monetary value of such plans as applied to concrete.   Finally, recognizing the trend toward the improper use of acceptance control charts for inspection of construction materials, these tools are reviewed in chapter VI. It is concluded that concrete acceptance control charts are inappropriate and should not be used in concrete inspection.

Di Cocco, J.B., and P.J. Ballair, Acceptance Sampling Plans for Rigid Pavement Thickness, New York State Department of Transportation, Federal Highway Administration.

In 1967, New York State initiated studies of quality assurance for portland cement concrete.  The ultimate goal is to institute a quality assurance program in New York for all concrete properties.  While such a program requires extensive preparatory studies for some concrete properties, historical data available for concrete pavements can be used as a first step toward this goal.  The shortcomings of the present sampling procedure for inspecting concrete pavement thickness are explained, and two considerably more efficient acceptance sampling plans are developed.  These sampling plans take into consideration the producer's and consumer's risks, the nature of the product, its criticality, and the available historical data.  Operating characteristic curves are given for both the present inspection procedure and the derived sampling plans.

Di Cocco, J.B., and W.W. Nuzzo, Concrete Pavement Thickness Measured by Two Methods, Publication No. 45-1, New York State Department of Transportation.

On two paving projects, slab thickness was measured at 25 test locations by coring and by a single manufacturer's ultrasonic method, and the results were compared for precision.   First, the difference between the thickness calculated from ultrasonic readings and that measured from the core was determined and compared for each test location.   Then, all measurements obtained by each method were grouped and compared for each project.  The first comparison showed that differences can be large and may occur often, but nothing could be concluded about relative precision.  Comparing the grouped data proved more meaningful, and inferences concerning precision could be drawn.   The sonic thickness for each location represents the average thickness of an area of about 2 ft (0.6 m) in diameter.  The core represents the average thickness of a much smaller 4-in- (101.6-mm-) diameter area.  Thus, core lengths should include more extreme values, and their standard deviations should be larger if the two methods are equally precise.  Since the standard deviations of sonic thicknesses were equal to or greater than those of corresponding groups of cores, it is concluded that sonic measurements are less precise than coring.  The costs of measuring with the two methods were also compared, and coring was found to be less expensive.

Dierstein, P.G., A Study of PCC Pavement Texturing Characteristics in Illinois, Publication No. FHWA/IL/PR-82-095, Illinois Department of Transportation, February 1985, 59 pp.

Seven textures (transverse tine, transverse broom, artificial turf, transverse roller, artificial turf/transverse tine combination, longitudinal tine, and longitudinal broom) were formed in the plastic surface of a continuously reinforced concrete pavement.   Construction observations indicated that separate machines for texturing and for applying curing compound are preferred since the timing of the two operations is sometimes incompatible.  During texturing, care must be taken to avoid overlapping transverse textures, edge damage, and surface deformation caused by the pressure of the device.   Friction tests indicated that grooved textures are superior to broom and artificial turf textures, with the artificial turf/transverse tine combination being the best.   A Macrotexture Index, based on both treaded-tire and smooth-tire friction numbers, shows promise as a surrogate texture-depth indicator.  The index can determine, with a high degree of certainty, whether a surface has a coarse, medium, or fine texture. Smoothness tests verified that surface texture can influence roughness, and that transverse-grooved textures are rougher than longitudinal textures.  Most motorists can easily detect when they are on the transverse roller texture, because its wider and deeper grooves result in a humming noise like that produced by rumble strips; therefore, the transverse roller texture was eliminated as a final finish candidate.  During winter storms, natural crosswind and vehicle-generated wind caused blowing snow to collect more on longitudinal tined and artificial turf textures than on the others.

Donnelly, D.E., Consolidation of Portland Cement Concrete Pavement Long Term Performance, Publication No. CDOH-DTP-R-80-1, Colorado Department of Highways, 1980.

In 1970, three concrete paving projects were selected to evaluate various parameters to improve the consolidation of concrete pavements.  Prior to this time, core drilling to verify pavement thickness revealed an unusual number of voids in spite of field attempts to hold the slump at 1 in (25.4 mm).  In Colorado, two main types of concrete mixes are used, one containing a fine aggregate mix and the other containing a coarse aggregate.  In addition to aggregate size, other parameters investigated included internal vibrators on the paver, vibrator eccentric diameter, speed, angle, height, paver speed, and slump of the mixes.

Dossey, T., H. Castedo, and B.F. McCullough, "Prediction of Concrete Properties Using Coarse Aggregate Chemical Composition Data," Transportation Research Record 1284, Transportation Research Board, 1990, pp. 1-7.

Regression models that predict the compressive strength, tensile strength, modulus of elasticity, and drying shrinkage of concrete made with several coarse aggregates are presented in this paper.  The findings are part of a comprehensive research study for determining the effect of aggregates on the performance of concrete pavements.  Using statistical analysis of laboratory test data from concrete samples made with eight commonly used aggregates of known chemical composition, regression models were developed to predict the concrete properties.  The predicted values were then compared with the laboratory test results, and the models were used to predict the properties of 11 additional untested coarse aggregates.  The predicted concrete properties were within the pavement concrete range reported for these types of concrete mixtures.  These prediction models can estimate preliminary information for coarse aggregates or coarse aggregate blends from chemical composition data before casting and testing of concrete samples.  This will allow for initial screening of proposed new sources of coarse aggregate or tentative blends of new or existing aggregate sources of known chemical composition.

ELE International, Inc. Micro Covermeter User Manual, 1994, 12 pp.

The ELE CT-4950A Micro Covermeter was designed to locate and size reinforcement bars, as well as to determine concrete coverage, making it a useful tool in evaluating in-place concrete structures.  This manual contains a brief description of the Micro Covermeter and provides instructions for its use.

ERES Consultants, Inc. Technical Memorandum for the Draft Report of Measurement and Specification of Construction Quality: Literature Survey Report for PCC Pavements, (for FHWA Contract No. DTFH61-94-C-00078), April 1995, 35 pp.

This memorandum presents the results of a literature search performed as a preliminary step to investigating the levels of variability in PCC pavement construction.  The intent of the literature survey was to identify information related to the following eight topics of interest:

• The level of quality in today’s construction.
• Which quality measurements can be assumed to follow a normal distribution.
• The presence and quantification of longitudinal, transverse, and vertical variability in construction.
• The effect of erroneously assuming the existence of normally distributed measurements.
• How lot sizes are selected to ensure measurements are normally distributed.
• What current acceptance sample sizes are large enough to provide sufficiently accurate measures of quality.
• The effect of variability on pavement performance.
• Interrelationships between quality characteristics.

Fast-Track Concrete Pavements, American Concrete Pavement Association, 1994, 31 pp.

To build a fast-track project, both the contractor and the agency must make some changes to traditional construction specifications and processes.  Often, this entails high early strength (fast-track) concrete, but it can also include revising opening criteria, construction staggering, joint construction, and worker responsibilities.  This document discusses background information and details for these changes.

Fernando E.G., R.S. Walker, and R.L. Lytton, "Evaluation of the Siometer as a Device for Measurement of Pavement Profiles," Transportation Research Record 1260, Transportation Research Board, 1990, pp. 112-124.

Highway engineers have always been concerned with providing pavements of acceptable serviceability.  The serviceability of a highway segment, which is largely a function of pavement roughness, is a widely used criterion for deciding when pavements are in need of rehabilitation.  For this application, various statistics are currently used as indicators of pavement serviceability, the most common being the present serviceability index.  These statistics are largely determined from measurements of pavement roughness.  Various devices and procedures have been developed for accomplishing these measurements.  Of practical necessity, devices for measuring pavement roughness must provide repeatable measurements at normal highway speeds.  In addition, devices should not require difficult calibration procedures; should be able to field-process collected data; and should be relatively inexpensive to own, operate, and maintain.   The Siometer, which is currently used by the Texas State Department of Highways and Public Transportation (SDHPT) for evaluation of pavement riding quality, holds promise as an instrument for the routine collection of profile data on a network-wide scale.   The Texas SDHPT has recently begun investigating the profile-measuring capability of the Siometer.  A unique feature of this device is the statistical modeling procedure for characterizing the vehicle on which it is installed, which lends portability to the Siometer.  In it, the parameters of the statistical model are determined in a self-calibration procedure that is run before profile data are collected.  To evaluate the applicability of the Siometer as a device for profile measurements, profile measurements with the Siometer were compared with those from a profilometer.

Flude, S.T., and D.J. Janssen, "Comparison of Air-Void Characterization for Various Concretes," Prepared for the 69th Annual Meeting of the Transportation Research Board, January 1990, 40 pp.

At present, the most widely accepted predictor of durability is the spacing factor, which is a parameter related to the maximum distance from any point in the cement paste to the boundary of an air void.  At best, this factor is a loose indication of durability, since the durability depends on more than just the paste content, the air content, and the void frequency.  Several studies have shown that parameters such as the specific surface and distribution of air voids, as well as the void frequency, the Philleo factor, and the air void content, can influence the durability of laboratory concrete.  Field samples were used to investigate these and other parameters.   Through such an investigation, the authors hoped to determine any additional parameters that may be used in conjunction with the spacing factor to more accurately predict durability.  Since no totally satisfactory method has been found to correlate the air void system to the prediction of durability of concrete, this paper provides improved air void characterization and methods for evaluating the durability of marginal concretes.

Ford, R.W., and T.L. Shelly, Water-Based Concrete Curing Compounds, Publication No. 604185, California Department of Transportation, June 1982, 33 pp.

Proprietary water-based curing compounds were compared with solvent-based compounds now used by Caltrans.  Water-based compounds protect concrete during the curing period, as well as solvent-based compounds, at a slightly lower cost.  A tentative specification for water-based curing compounds is included in this report.

Fowler, G., and W. Gulden, Investigation of Location of Dowel Bars Placed by Mechanical Implantation, Georgia Department of Transportation, Office of Materials and Research, May 1983, pp. 1-31.

This report describes a phase of a study concerned with the restoration of load transfer to existing jointed concrete pavements.  Five projects were selected to determine the location of dowel bars placed by mechanical implantation and basket assemblies.  A 1-percent stratified random sample of bars was selected for coring to determine depth, horizontal and vertical rotation, and vertical alignment.   Measurements were also made with a metal detector on additional bars.  The study found substantial problems with the mechanically placed dowels with respect to alignment and rotation.  Much better results were obtained with the basket assemblies.  It was noted that sawcut location affected longitudinal alignment to a large extent on both basket and implanted dowels.  No pavement distress related to dowel bar misplacement had occurred after 3 years of traffic, even for locations with dowel bars with extremely large horizontal and vertical rotation.

Friggle, T., "Results of an Analysis of a Ride Quality Specification for Hot-Mix Asphaltic Pavements and Portland Cement Concrete Pavements in Texas," Prepared for Transportation Research Board 75th Annual Meeting, January 1996, 21 pp.

In 1993, the Texas Department of Transportation (TxDOT) initiated the use of a ride quality specification for hot-mix asphalt concrete (HMAC) and portland cement concrete (PCC) pavements.  The specification allows payment incentives and disincentives based on the profile index, defined as the ratio of vertical deviations in the surface over a length of pavement.  This paper documents an analysis of the data collected after initial use of the specification and modifications made to the specification based on the analysis.  The results indicated a high probability of a smooth ride with HMAC pavement, while a smooth ride on concrete pavement was less likely to occur.  Certain types of concrete placement, such as hand-finished concrete or very short segments, were unlikely to produce a surface smooth enough to satisfy the specifications.

Fuchs, F., "An Overview of European Practice," Prepared for Transportation Research Board 73rd Annual Meeting, January 1994, 7 pp.

This paper addresses noise, skid resistance, and comfort levels provided by different pavement textures.  In Europe, an exposed aggregate finish is considered the most advantageous method for obtaining optimum surface characteristics for safety, ride quality, and noise.  It is, however, important to use hard and polish-resistant aggregate in the surface layer.  Furthermore, specifications can be adapted to allow agencies to factor in local priorities, climatic conditions, and budgetary constraints.

Gerhardt, B.B., The Effect of Vibration on the Durability of Unreinforced Concrete Pavement, Publication No. CDOH-P&R-R&SS-75-2, Colorado Department of Highways, May 1975, pp. 12-53.

Because a noticeable difference in durability of concrete pavements in Colorado seemed to be associated with differences in consolidation and void content of the concrete, an effort was made to determine the relationship.  After extensive laboratory work to determine the basic characteristics of the designed mixes, test sections were laid out at four different locations.  These test sections had internal vibration by vibrators having various diameter eccentrics and vibration speeds.  In addition, the angle of the vibrators was changed, as was the height of the vibrators, the paver speed, and the slump of the mixes.  Performance of these test sections was observed from May 1970 until May 1975.  Wear in the wheelpaths due to studded tires has been approximately 0.1 in (2.5 mm) per year in the heavily traveled non-test areas of the experimental sections.  Wear in the test sections has averaged 0.07 in (1.8 mm) per year, but it has not varied directly with the consolidation effort.  Although statistical evidence indicates that good field control and reasonable vibration will ensure at least 97-percent consolidation and sound concrete, there does not seem to be a direct relationship between vibration effort and resistance to surface abrasion.  Other factors such as curing, mix design, water-cement ratio at the surface, and aggregate type appear to control surface hardness.

Glossary of Highway Quality Assurance Terms, Transportation Research Circular 457, Transportation Research Board, April 1996, 18 pp.

Highway quality assurance, like many other specialized subject areas, has a unique language of technical terms and expressions with very specific meanings.  Some of these terms are not well-understood, and their use is subject to a variety of interpretations.  Moreover, highway quality assurance terminology is continually changing to keep pace with advances in quality assurance.  This document contains terms of common usage and accepted practice.

Goulias, D.G., "Development of Performance-Related Specification Pay Schedules," Prepared for Transportation Research Board 74th Annual Meeting, January 1995, 12 pp.

In recent years, highway agencies and constructors have used improved construction techniques and materials for better pavement quality.  However, newly constructed asphalt and portland cement concrete pavement surfaces are not always being built to the desired level of ride quality.  In 1984, AASHTO conducted a survey of smoothness specifications to recommend a draft smoothness specification for State highway use.   Since then, several agencies have undertaken the development of new smoothness specifications.  One of the objectives of these specifications is to provide rational and defensible pay schedules.

A method for defining rational and defensible performance-related pay schedules for smoothness of flexible pavements is presented in this paper.  Based on the level of smoothness achieved by the contractor, rewards for superior pavement quality and penalties for inferior quality are defined.  Such rewards were defined by examining the influence of initial pavement roughness on pavement performance and the resultant economic effects on the users and the agency.  Furthermore, the effect of design parameters such as design period, traffic and reliability level, material properties, and cost was examined through a sensitivity analysis.  The possibility of defining stepped and gradually increasing payment schedules is presented with recommendations.

Goulias, D.G., "Conceptual Development of a Performance-Based Specification for Pavement Smoothness," Prepared for 1997 Transportation Research Board Annual Meeting, January 1996, 11 pp.

This paper presents the methodology for the development of a performance smoothness specification.  The methodology takes into consideration the deviation of the as-built pavement for the design quality (i.e., target value) and evaluates the consequences on pavement performance.  Then, based on the achieved level of smoothness by the contractor, incentive plans for superior pavement quality and penalties for inferior quality are defined.  Such pay schedules are defined by examining the influence of pavement roughness on user and agency costs (in terms of vehicle operating cost, pavement maintenance, and rehabilitation costs).  Furthermore, the effect of design parameters, such as design period, traffic and reliability level, material properties, and cost, on the incentive plans was examined through a sensitivity analysis.

The methodology for defining a performance specification for pavement smoothness identified in this study is applicable to any condition and may be used by highway agencies elsewhere.

Grady, J.E., and W.P. Chamberlin, "Groove-Depth Requirements for Tine-Textured Pavements," Transportation Research Record 836, 1981, pp. 67-76.

This paper discusses the depth required for grooves on new tine-textured concrete pavements in order to ensure an adequate skid resistance over their entire design life.   It is based on measures of texture depth and skid resistance, with both ribbed and smooth tires, made on new to 5-year-old pavements in New York.  Initial groove depth needs of 3/16-in (4.8-mm) minimum were calculated from two values estimated from the study data: (1) minimum groove depth (0.050 in [1.3 mm]) to ensure adequate skid resistance with a minimum legal tire tread and (2) mean groove wear rate (0.013 in [0.3 mm] /million vehicle passes).  Groove depth measurements on new concrete pavements and bridge decks indicated 21 and 14 percent compliance, respectively, with the proposed new standard of 3/16-in (4.8-mm) minimum, and 60 and 44 percent compliance with the current standard of 2/16-in (3.2-mm) minimum.  Prospects for improving the compliance rate were judged to be most promising in two areas—increasing the awareness and motivation of construction personnel and improving the design of tining rakes over those now in use.   Although the findings of this study are specific to standards and conditions in New York, the methodology should be of general interest.

Gray, R.J., "Variability of Compressive Strength Test Results," Concrete Technology Today, June 1990, 11(2): 1-4.

This article focuses on the variability in compressive test results obtained from different laboratories for the same batch of concrete.  An estimate of this between-laboratory variability is derived from data obtained in interlaboratory or comparative testing programs that are operating in the three largest metropolitan areas of British Columbia and Alberta, Canada.  Within-laboratory information is also presented. It was concluded that both the within- and between-laboratory precision of the standard test method for determining the compressive strength of cylindrical portland cement concrete test specimens vary linearly with the compressive strength of the test concrete.  Results of the within-laboratory study imply that on the basis of test error alone, the difference in absolute value of two test results obtained in the same laboratory on the same material will exceed 10 percent of the average compressive strength of the test concrete about 5 percent of the time.  There is reason to question one or both of the test results only if such a difference is larger than this value.   Results of the between-laboratory study imply that on the basis of test error alone (including both the within- and between-laboratory components), the difference in absolute value of two test results obtained in different laboratories on the same material will exceed 15 percent of the average compressive strength of the test concrete about 5 percent of the time.  There is reason to question one or both of the test results only if such a difference is larger than this value.

Greer, W.C., Jr., "Evaluation of Strength Tests and Acceptance of Concrete Pavements," Proceedings: Fourth International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, Publication No. FHWA-RD-89-208, April 1989, pp. 375-383.

One of the most troublesome phases of a concrete pavement construction project can be the determination of whether the strength of the concrete meets the project specifications.  This determination can be complicated by the fact that the flexural strength test is often specified for acceptance, and there is often little or no understanding of the procedures and precision of this test.  The quick placement of large volumes of concrete for pavement construction projects means that a million dollars or more worth of concrete can be "on the ground" before the first acceptance test is ever performed.  If questions arise regarding the validity of the acceptance tests, then an understanding of the inherent variations in the test is necessary for proper evaluation of concrete acceptability.

This paper presents analyses to determine the statistical parameters for flexural strength test results for more than 1 million yd³ (0.765 million m³) of concrete pavement constructed at the Atlanta International Airport.   Parameters for within-test statistical variations are presented so that the quality of the testing agency personnel can be evaluated.  Parameters for the between-test statistical variations are presented so that the quality of production by the contractor can be evaluated.  The results of the analyses indicate that the within-test variations can approach the between-test variations, and this greatly contributes to confusion and misunderstandings.  The analyses also show that two flexural strength test results from the same batch of concrete can be expected to vary by as much as 100 psi (689.5 kPa) and not be considered suspect 95 percent of the time.  The difference between the average flexural strengths of each of two batches of the same concrete mix in the laboratory can differ by as much as 75 psi (517.1 kPa) and not be considered suspect 95 percent of the time.  Procedures for adjusting the actual flexural strength test results upward based on additional thickness over the design thickness, or downward based on deficient thickness from the design thickness, are given.

Grove, J.D., "Blanket Curing to Promote Early Strength Concrete," Transportation Research Record 1234, Transportation Research Board, 1989, pp. 1-7.

Fast-track concrete has proven to be successful in obtaining high early strengths; however, this benefit does not come without cost.  Special Type III cement and insulating blankets to accelerate the cure add to the expense.  This research was intended to determine the benefit derived from the use of insulating blankets to accelerate strength gain in three concrete mixes using Type I cement.  The goal was to determine mixes and curing procedures that would result in a range of opening times.   This determination would allow the most economical design for a particular project by tailoring it to a specific time restraint.  Three mixes of various cement contents were tested in the field.  Flexural beams were cast for each mix and tested at various ages.  Two test sections were placed for each mix, one section being cured with the addition of insulating blankets and the other being cured with only conventional curing compound.  Concrete with fast-track proportions, Type I cement, and insulating blankets reached the required strength in approximately 36 h.  A standard mix using the blankets reached the required strength in approximately 48 h, and the fast-track proportions with Type I cement without blankets reached that strength in about 60 h.   The results showed a significant improvement in early strength gain with the use of insulating blankets.

Hall, M. "Early Strength Testing of Concrete Cores and Cylinders," Transportation Research Record 1478, Transportation Research Board, 1995, pp. 82-89.

During the 1989 construction season in Wisconsin, six projects built by four different concrete paving contractors were studied to assess the in situ early strength of concrete pavements, the early strength of lightly insulated field-cured concrete cylinders, and the 28-day strength of paving concrete.  The projects were also studied to establish the relationship between cylinder and in situ strength typical on paving projects in Wisconsin.  Testing results indicated that most pavements constructed in warm weather attain compressive strengths of 20.7 MPa (3,000 psi) to 24.1 MPa (3,500 psi) in 3 days or less, approximately 95 percent of the paving grade concrete has a 28-day compressive strength of more than 27.9 MPa (4,050 psi), and the compressive strength of lightly insulated cylinders cured in the field provides a reasonable measure of the in situ compressive strength of the pavement as measured in core tests.

Hankins, K.D., A Review of Tines Texturing of Portland Cement Concrete Paving, Publication No. FHWA/TX-86/43+187-10, Texas State Department of Highways and Public Transportation, 1984, 34 pp.

This report describes the tests conducted by the Transportation Planning Division, Research Section of the State Department of Highways and Public Transportation, to review the methods and effectiveness of tine-texturing of PCC pavements in Texas.  It includes average texture values, percent by texture groups, wear measurements, operator variations, and surface variations within a project.  The opinions, concerns, and comments of several engineers in various Districts were also discussed.  It was concluded that the majority of the Districts have experienced trouble in obtaining the required tine texture levels.  They are also concerned with the damage and possibility of structural strength loss caused by tining and do not believe the possible reduction in wet weather accidents achieved by tines is worth the possible reduced loss in structural life.  Recommendations were made to reduce the average texture depth requirements and delete the minimum texture depth requirement.  Minimum cross slope requirements and alternate methods of finishing were suggested.  Also, revisions to the roughness requirements were suggested, as was additional study of concrete finishing techniques.

Harrison, R., C. Bertrand, and W.R. Hudson, "Measuring the Smoothness of Newly Constructed Concrete Pavement for Acceptance Specifications," Proceedings: Fourth International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, Publication No. FHWA-RD-89-208, April 1989, pp. 601-614.

This paper presents a brief historical background and reports the key results of an AASHTO survey to ascertain States' practices for measuring and evaluating pavement smoothness.  A modification to the AASHTO guide specification is then discussed, as are implications of the bonus and penalty categories.  A high-resolution profiling device, the Dipstick, has been tested with other roughness devices, and the results are presented.  Finally, a California-type Profilograph was employed on newly constructed reinforced concrete to test the proposed specification prior to its trial adoption.   Problems with the Profilograph were identified that could make the proposed standards difficult to implement.  It was concluded that a combination of Profilograph and Dipstick instruments, together with a modification to the categories within the Texas draft specification, would result in a more equitable and enforceable standard.

Haviland, J.E., and R.W. Rider, "Construction Control of Rigid Pavement Roughness," Highway Research Record 316, Highway Research Board, 1970, pp. 15-32.

Results of a 2-year study of cause-effect relationships involved in roughness of concrete pavements are reported.  Data were derived from analog measurements obtained in each wheelpath within hours after concrete placement on randomly selected pavements, as well as from qualitative observations of paving methods.  Sampled construction consisted of 184 sections of 1- and 2-lane pavement built under 62 different contracts with 8 different form-type finishing machines and 3 different slipform pavers.   Statistical analysis was held to a minimum by uncontrolled interactions, but five factors were found to be significant in relation to roughness: backing up of the last finishing machine, absence of a float, use of fewer than three screeds, use of a crown section as compared to a uniformly sloping section, and lane-at-a-time paving.

Nine other construction phenomena producing roughness, common to many projects but found less frequently than these five, are also covered in some detail.

Hegmon, R.R., "A Close Look at Road Surfaces," Public Roads, Summer 1993, pp. 4-7.

To most people, including the majority of readers of Public Roads, road surfaces are just gray areas stretching for miles and miles.  Road surfaces are expected to provide safe driving conditions in dry and wet weather, provide a smooth and quiet ride all the time, minimize splash and spray during rain, provide good visibility under adverse conditions, and have a long service life.

A close look at the surface reveals many features, including texture, which is needed to provide skid resistance, reduce splash and spray in heavy rain, and reduce headlight glare in night driving.  But texture may increase noise and reduce the life of both pavement and tire. Further, as roads age and deteriorate from the effect of heavy truck traffic and weather, signs of distress appear. Road roughness is one sign of distress and is detrimental to both pavement life and ride quality.  This article discusses only road roughness, how roughness is measured, and the effect of roughness on the highway user and on pavement life.

Henley, R.G., D. Malkemus, D.W. Fowler, and A.H. Meyer, "Evaluation of Chace Air Indicator," Transportation Research Record 1062, Transportation Research Board, 1986, pp. 55-62.

An evaluation of the Chace Air Indicator (CAI) was made for use in PCC construction.   The CAI indicated higher values than the pressure method at low air content and lower values at high air content.  The CAI readings corrected for mortar content and the Chace factors produced values approximately 15 percent higher than the pressure method over all ranges of air content.  A regression analysis procedure was used to determine a curve correction to account for the difference between the Chace factor- and mortar-corrected CAI readings and those of the pressure meter.  An indication of the reliability of the results was represented by confidence intervals.  The CAI does not have sufficient accuracy to measure the air content of concrete for job control purposes.

Heston, D., and J. Wojakowski, Portland Cement Concrete Pavement Joint Faulting on US-69, Miami Co., Kansas, Kansas Department of Transportation, July 1992, 19 pp.

This paper presents the results of a joint faulting survey performed on U.S. 69 in Miami County, Kansas.  Twenty-three test sections were placed with various adjustments to vibrator settings, concrete admixtures, and other special features.   The results showed that faulting increased with pavement age and traffic loadings.   The results also showed that pavements with greater concrete density tended to fault less.

Huft, D.L., "Analysis and Recommendations Concerning Profilograph Measurements on F0081(50)107 Kingsbury County," Transportation Research Record 1348, Transportation Research Board, 1992, pp. 29-34.

In 1990, the South Dakota DOT noted significant discrepancies between its ride-quality measurements and those taken by a contractor paving a PCC project.  The contractor's measurements were consistently smoother than SDDOT's and would have generated incentive payments approximately twice as large.  About half of the observed difference could be attributed to increased pavement roughness after paving, but the rest appeared to result from differences between the department's manual profilograph and the contractor's computerized unit.  Analysis revealed that a numerical filtering algorithm used by the computerized profilograph strongly attenuated profile features with wavelengths shorter than 10 ft (3.0 m).  Such attenuation was observed directly on the computerized unit's profile traces.  Because of the attenuation, SDDOT considered the computerized measurements unsuitable for calculating incentive payments.  However, SDDOT could not use its own measurements as a basis for payment because they were not taken within the specified 48-h period after paving.

To estimate a fair incentive payment, SDDOT developed a correlation between the computerized and manually interpreted profile indexes for the project.  Using the correlation, SDDOT awarded an incentive payment approximately midway between its original estimate and the contractor's.  SDDOT has suspended use of computerized profilographs pending improvement of the filtering algorithm.  Preliminary experiments indicate that although the computerized profilograph's first-order filter attenuates profiles too strongly and produces artificially low profile indexes, a third-order filter might generate higher profile indexes than does a manual interpreter.  This suggests that a second-order filter might best approximate a human's visual interpretation of the profile.   Further research is needed to confirm this hypothesis and to establish a foundation for standard filtering procedures.

Hughes, C.S., Variability in Highway Pavement Construction, National Cooperative Highway Research Program, Synthesis of Highway Practice 232, 1996, 38 pp.

The quality of highways has always been a major concern to highway engineers and contractors.  The AASHTO Quality Assurance Guide Specifications use the variability of material and construction processes as one of the measures to assess quality.   This synthesis of information defines several measures of variability, but concentrates on the use of standard deviation as the usual variability measure.  The synthesis updates typical variabilities found in material and construction processes.   Also included are discussions of current research activities as related to variability, how variability can be used in the development of specification limits, the state of the practice of incentives and disincentives in specifications, and the need for additional information on the variability of several material and construction processes.

Of the many important findings of the AASHO Road Test, one was a revelation as to the greater-than-expected magnitude of the variabilities encountered in the construction of the pavements in this major study.  Since the findings of this study were reported, many reports of studies on typical variability in highway construction have been conducted by both the FHWA and various DOT’s. More recently, with greater use of computers to accumulate data from materials quality control and acceptance testing, both DOT’s and contractors have developed bases for quantifying material and construction variability and other important properties.

From the data gathered in this synthesis, it is obvious that variability has a relatively wide range of values for each test procedure.  One of the factors that influences this variability is the period of time, distance, area, or quantity of material over which the variability is measured.  This information was not always available in the references found. It is important that in the development of a specification, data be used prudently.  Verification of the variability under conditions of proposed usage is encouraged.

Hughes, C.S., A.L. Simpson, R. Cominsky, K. Maser, and T. Wilson, Measurement and Specification of Construction Quality, Volume I, Publication No. FHWA-RD-98-077, Federal Highway Administration, May 1998, 183 pp.

This study consisted of testing six projects, three hot-mix asphalt concrete (HMAC) and three portland cement concrete (PCC).  The primary objectives were to: (1) determine how current quality control test results vary in construction projects and how this variability affects pavement performance and (2) assess the suitability of current methods of quantifying materials and construction quality and quality variability, and develop and improve methods that minimize current shortcomings.

Volume I of this report contains information about the data analysis.  Volume II provides information about the data collected and use of GPR to determine pavement thickness.  This volume also contains univariate data on each of the tests performed on samples taken from the projects used in this study.

Huschek, S., Measurements on Test Stretches, Final Report, Publication No. 240/7, Technische Universitat Berlin, May 1994, 22 pp.

The Technical University of Berlin prepared this report about the measurements of texture, tire/road noise, and skid resistance on two German test stretches built for the BRITE/EURAM project BE 3415, "Optimization of the Surface Properties of Concrete Roads in Accordance With Environmental Acceptance and Traffic Safety."  The "Garlstorf" test stretch includes 13 sections of different textures, and the "Wittstock" test stretch includes 29 sections of different textures.  Both were investigated a few weeks after opening, and the "Garlstorf" test stretch was investigated a second time approximately 1 year after the first measurements.

The texture measurement results showed that the demand for high amplitudes in the short macrotexture wavelength and low amplitudes in the megatexture is met only in a few cases.   Trailer measurements using the World Road Association (PIARC) tire favor longitudinally structured cement concrete surfaces.

The positive influence of the shortwave macrotexture and the negative influence of the megatexture on the acoustical road surface properties cannot be proven by the regression analysis of the spectral texture measures and the different tire/road noise measurement results.  Regression analysis shows no correlation between the acoustical and the frictional properties of road surfaces.

Idorn, G.M., "Concrete Durability & Resource Economy," ACI Compilation 24, American Concrete Institute, 1993, pp. 22-27.

Concrete of certified, long-term durability, tailored to its performance requirements, will become a basic element in the development of resource economy policies worldwide.   The article discusses concrete materials and concrete processing and testing, and points out the need for innovation in modern instrumentation and test methods for site monitoring of effective compaction.  Quality control should be based on scientific, physico-chemical monitoring methods.  It is expected that during the next decade, on-site monitoring of the processing of fresh concrete and of early curing will completely replace conventional quality control by means of sample testing.  Comments are made on research sponsored by litigation and forensic engineering.  The Strategic Highway Research Program is noted as having created more cooperation in the planning and management of research in concretes than ever before.

Influence of Design Characteristics on Concrete Durability, Missouri Highway and Transportation Department, March 1990, 23 pp.

The primary objective was to investigate the influence of cement factor, percent air, maximum coarse aggregate size, and percent of total aggregate as sand on the performance of concrete subjected to freeze-thaw cycling.  An important secondary objective was to document air void system characteristics of hardened concrete with these same design factors.  Data in this report include durability and expansion of freeze-and-thaw beams, air void system characteristics, flexural strength, and compressive strength in conjunction with concrete design factors and fresh concrete characteristics.

Resistance to freeze-and-thaw increased as maximum size of coarse aggregate decreased.   Neither compressive strength nor flexural strength changed with maximum size of coarse aggregate.  Based on the results of this study, a desirable concrete pavement mix design using D-crack-prone coarse aggregate of the materials tested would be: 0.5-in (12.7-mm) maximum size coarse aggregate, 38 percent of aggregate as sand, 6.5 sacks of cement/yd³ (5.0 sacks/m³), 6.0 ±1.5 percent air by volume, and 2.5-in (63.5-mm) maximum slump.

Innovative Contracting Practices, Transportation Research Circular 386, Transportation Research Board, December 1991.

Historically, transportation agencies in the United States have been conservative in their construction contracting practices and have tended to continue the status quo rather than assume the risks associated with change.  Innovative contracting techniques have developed more in foreign countries than in the United States.  Before U.S. Federal and State agencies can make greater use of these techniques, the issues, options, potential advantages and disadvantages, steps required, and legal and economic impacts must be better understood.

In order to help develop this understanding and facilitate greater innovation in government and industry, TRB formed its Task Force on Innovative Contracting Practices.   The task force examined the processes, as they affect quality and cost, under which U.S. and foreign agencies contract for construction.  This report summarizes the findings of the task force, as well as some governmental initiatives that have already taken place as a result of its deliberations.

An Investigation of Frictional Properties of Wire-Combed PCC Pavement Surfaces, Publication No. FHWA/MO-78/3, Missouri Highway and Transportation Department, September 1982, 80 pp.

This report involves PCC pavements constructed with surface textures produced by a wide variety of wire combs.  A small amount of testing was also performed on PCC pavements with other textures as a follow-up of previous research on frictional properties.  A limited amount of noise evaluation by rating panels and sound level meters was conducted to assist in selection of an optimum tine spacing for wire combs on future PCC pavement projects.  This report includes a brief description of each major project with summaries of friction number tests, sand patch texture depth tests, and sound-level measurements.

Irick, P.E., S.B. Seeds, M.G. Myers, and E.D. Moody, Development of Performance-Related Specifications for Portland Cement Concrete Pavement Construction, Publication No. FHWA-RD-89-211, Federal Highway Administration, May 1990, 271 pp.

The primary product of this study was a demonstration PRS for PCC pavement construction.  The system is designed to consider three key factors (PCC strength, slab thickness, and initial serviceability) in assessing an as-constructed pavement delivered by a contractor and calculating an appropriate reward or penalty.

Many pavement performance prediction relationships and PCC property prediction equations were evaluated to develop the performance-related aspects of the new system.   In addition, a rather intensive experimental laboratory study of PCC material properties was conducted to develop better multi-factor prediction relationships.

The demonstration PRS was developed using a computerized spreadsheet program.  It was designed to be parallel to the demonstration PRS system developed under NCHRP Project 10-26A for asphalt concrete pavements.  As a result of the study, recommendations were made for further research in several key areas related to PRS and field and laboratory studies.

Janoff, M.S., Pavement Smoothness, Information Series 111, National Asphalt Pavement Association, 1991.

This publication describes the benefits of smooth pavements and the adverse effects of pavement roughness.  In addition, examples of methods to construct smooth hot-mix asphalt (HMA) pavements are provided, along with a discussion of the economics of smooth HMA pavements.

The benefits of pavement smoothness include increased roadway safety, vehicle operating speeds, ride quality, and drive comfort; improved long-term pavement performance and vehicle behavior (e.g., braking, steering, and control); and reduced annual maintenance costs, vehicle operating costs, and driver fatigue.  Methods to improve pavement smoothness include proper specifications, incentives and disincentives, an HMA product designed for the specific application, properly trained and utilized personnel, better transportation of the HMA from the mixing facility to the site, and a high-quality paving process.

Jensen, C.C., Pavement Smoothness, Irving F. Jensen, 1987.

This article discusses Jensen Co.’s experience in using the profilometer, including some "best practices" types of recommendations.  The article also discusses profilometer specifications and recommends the following for "quality control through the profilometer specification":

• Incentive or bonus clauses.

• Elimination of 3/10 must-grinds on otherwise superior quality pavement.

• Uniform, stable padline.

• Base construction or soil modification on bad subgrades.

• A range of numbers, such as recommended by the American Concrete Pavement Association, to facilitate realistic quality control under the varying conditions of subgrade and specification design requirements.

• Contractors should own and use profilometers daily to improve their results.

Johnson, J.L., D.G. Zollinger, and S. Yang, Guidelines for the Construction of Fast-Track Concrete Pavement Intersections, Publication No. FHWA-TX-94-1385-1F, Texas Department of Transportation, June 1994, 152 pp.

This report documents a review of Texas Department of Transportation (TxDOT) design and construction practices with regard to accelerated concrete pavement construction of heavily traveled intersections.  The review focuses on the design and construction measures taken by TxDOT to address the impact of reconstruction of such pavement facilities.  The review consisted of a field investigation that considered current construction specifications, as well as the development of guidelines based on an assessment of the impact present practices may have on performance of the constructed pavements.

It was determined that the use of fast-track paving techniques requires coordinated construction planning to take advantage of the benefits offered by this construction process.  Concrete mix proportioning can be supplemented by special admixtures to accelerate the time of set, but this must also meet the workability requirements associated with the transportation, placement, finishing, and curing of concrete.

It is also beneficial to the construction supervisor to qualify the concrete mixture with respect to strength gain for a given set of weather conditions.  Laboratory work was conducted to support the development of the mix qualification process.

Klemens, T.L., "Ultra-Smooth Slab Boosts Contractor's Profit," Highway and Heavy Construction, 133(3): 44-46.

In mid-1987, Delaware began one of its largest highway projects in recent years, and the first using the State's new smoothness standards.  Under those guidelines, payment for concrete paving is tied to the smoothness of the finished roadway.  The contract also provides for a bonus to be paid for very smooth pavements.  The contractor is using a special grade-control device to place the ultra-smooth concrete slab.  A mobile stringline mounted on an extended wheelbase rolls along the centerline side of the paver, averaging out slight grade irregularities.  The smoothness of the pavement is measured by a California-type profilograph.

Komlos, K., F. Kruml, and Z. Homolka, "Judgment of Concrete Quality in Transportation Structures," Transportation Research Record 652, Transportation Research Board, 1977, pp. 76-80.

This paper deals with the present Czechoslovakian method for judging the quality of fresh and hardened concrete used in transportation structures.  Standard methods and criteria are presented for estimating concrete properties for different types of structures.  In the case of hardened concretes, destructive and nondestructive testing methods are analyzed and evaluation techniques are given.  The problems of quality control of cements and aggregates are studied. The judgment of the acceptability of fresh concretes in relation to their composition and workability is also analyzed.   Requirements are presented for such properties as concrete strength and properties related to short- and long-term deformation.  Statistical evaluation is emphasized, and acceptability criteria for safety, homogeneity, and economy are presented.

Kopac, P., Performance-Related Specifications, Publication No. FHWA-SA-97-098, Federal Highway Administration, 1998.

This brochure provides an overview of PRS.  It explains the background and elements of PRS, lists some general characteristics of good specifications, and discusses the future in research and development of PRS.

Kosmatka, S.H., "Compressive Versus Flexural Strength for Quality Control of Pavements," Concrete Technology Today, December 1985, 6(4): 4-5.

This article discusses the advantages of using compression-test cylinders as opposed to flexural-test beams for the control of concrete.  A relationship between flexural and compressive strength for various aggregate combinations is presented.

Kraft, L.M., A Study of Concrete Consolidation, Publication No. 930-052, Alabama State Highway Department, Bureau of Public Roads.

In some instances, concrete pavements in Alabama have developed an undesirably high number of air and water pockets (as found in pavement cores).  The presence of these pockets has been attributed to inadequate compaction of the fresh concrete.  It is the purpose of this study to establish the effect that several of the variables that influence the compactability have on the quantity of entrapped air in the vibrated concrete.  The variables studied were as follows: (1) three coarse aggregates (varying in size and shape), (2) two vibrator frequencies with three amplitudes (spud-type vibrators), (3) variation in vibrating time, and (4) three thicknesses of concrete (6, 10, and 18 in [152.4, 254.0, and 457.2 mm]).  The quality of the vibration effort was measured by the entrapped air content of the vibrated concrete; the less entrapped air, the better the vibration.  For stiff mixes, the results of this investigation demonstrate the following:

• The percentage of entrapped air is not significantly reduced as the vibration time is increased beyond 5 seconds.

• The percentage of entrapped air can be greatly influenced by the characteristics of the coarse aggregate in the mix.

• An increase in the vibrator amplitude or frequency does not significantly reduce the percentage of entrapped air.

• The percentage of entrapped air decreases as the thickness of concrete increases from 6 to 18 in (152.4 to 457.2 mm).

• The compressive strength of concrete specimens with large volumes of entrapped air were generally greater than 3,000 psi (20.7 MPa); however, higher strengths could be obtained if the entrapped air content could be reduced, thus offering more efficient use of the cement in the mix.

Kraft, L.M., "Compaction of Concrete Slabs by Vibration," American Concrete Institute Journal & Proceedings, 68(6): 462-467.

Large air and water pockets have been observed in the cores taken from well-proportioned vibrated concrete pavements.  Several parameters that may influence the volume of entrapped air in thin concrete sections compacted with spud vibrators are studied.  Laboratory test results suggest that it is difficult to eliminate the entrapped air content in concrete slabs of stiff concrete compacted with spud-type vibrators and for moderate vibration times and vibrator amplitudes and frequencies.   The use of a surcharge may be beneficial in reducing the entrapped air content, and a crushed stone concrete mix may yield lower entrapped air content than a rounded stone mix.

Ksaibati, K., S. Asnani, and T. Adkins, "Factors Affecting the Repeatability of Pavement Longitudinal Profile Measurements," Transportation Research Record 1410, Transportation Research Board, 1993, pp. 59-66.

When looking at the accuracy of profilometers, most agencies are mainly concerned with hardware precision rather than the errors caused by the human operators or environmental factors.  The Wyoming Transportation Department and the University of Wyoming conducted a joint research project to determine the effect of these two factors on the accuracy and repeatability of roughness and rut-depth measurements.  The Wyoming Transportation Department's road profiler, which is a duplicate of the South Dakota road profiler, was utilized in this study.  Thirty-six test sections were tested by three different operators to determine the effect of human factors on measurement repeatability.   In addition, a concrete test section was monitored and tested several times in the 1991 testing season to examine the effect of different combinations of environmental factors on the measured roughness.  The data collected were then tabulated and statistically analyzed.  This paper summarizes the design of the experiment, describes the data collected, and provides specific conclusions with regard to the effect of human and environmental factors on the accuracy of roughness and rut-depth measurements.

Kulakowski, B.T., and C. Lin, "Effect of Design Parameters on Performance of Road Profilographs," Transportation Research Record 1311, Transportation Research Board, 1991, pp. 9-14.

Road profilographs are commonly used to measure roughness of new and newly surfaced pavements.  Because new pavements are usually smooth, profilographs must have high measuring sensitivity, particularly in the range of profile wavelengths responsible for dynamic pavement loading applied by heavy trucks and for ride comfort.  Simple analytical and computer models were developed to examine the effects of basic design parameters on the performance of California and Rainhart profilographs.  It was found that the quality of measurements obtained with the two profilographs could be improved by modifying some of the design parameters (e.g., length of main truss and number and spacing of supporting wheels).  The improvement should be more significant for the California profilograph.  The design parameters of the existing Rainhart profilograph are close to the values recommended in the paper.

Kunt, M.M., and B.F. McCullough, Improved Design and Construction Procedures for Concrete Pavements Based on Mechanistic Modeling Techniques, Publication No. FHWA/TX-92+1169-5F, Texas Department of Transportation, June 1992, 94 pp.

This report describes an improved set of concrete pavement design and construction procedures.  In developing these improvements, the researchers used a systems approach to incorporate material characterization subsystems and mechanistic techniques into the JRCP-5 computer program.  The data obtained from such an approach were then used to develop, analyze, evaluate, and implement the best procedure for designing concrete pavement reinforcement and for determining pavement sawing time and depth.   Whereas the original models used to characterize concrete properties could not distinguish the effect of coarse aggregate types (CAT), the improved model now has this capability. Because several aggregate sources are used in Texas, incorporation of the effect of CAT substantially improved the prediction models.  Additionally, the researchers updated the transverse reinforcement formula according to the findings of CTR Project 459 and developed a probabilistic sawing depth and time prediction model, with all improvements and updates subsequently input into the JRCP-5 computer program.  The report concludes with recommendations for improving the prediction accuracy of the models.

Lane, D.S., and G.C. Clemena, Determination of Concrete Quality Characteristics for the Development of a Performance-Related Specification for Concrete Pavements, Work Plan, Virginia Transportation Research Council, April 1995, 6 pp.

In 1995, Virginia DOT specifications for hydraulic cement concrete for rigid pavement construction were described as an "inconsistent blend of performance and prescriptive requirements."  Quality assurance procedures rely primarily on flexural testing of beams by centerpoint loading, a test with high variability.  Consequently, the properties of the pavement concrete are less well-known than is desirable, and virtually nothing is known about the mechanical properties of the actual pavement, which is, in fact, the most crucial piece of information for determining acceptability.

This work plan describes the details of a project being conducted by the Virginia Transportation Research Council (in cooperation with FHWA).  The purpose and scope of the project is to evaluate the strength properties of concrete paving mixtures in the laboratory, to determine the relationships between compressive strength, tensile strength, flexural strength, and stress-wave propagation.  These relationships were to then be verified by field testing on construction projects using the same concrete mixtures evaluated in the laboratory.  The ultimate goal of the project is to collect the data necessary to develop a PRS, thereby improving the specifications and quality assurance procedures for hydraulic cement concrete pavements.

Larson, R.M., Proposed 1994 Field Testing and Updated Work Plan, Technical Working Group on PCC Surface Texturing, March 1994.

The field study referenced in this memorandum would address depth of transverse and longitudinal tining and evaluate possible non-tining alternatives to minimize noise while providing adequate friction characteristics.  The memo contains an updated work plan and guidelines for evaluating test sections planned for 1994 construction or for previously constructed sections, as well as a tentative scope of work for NCHRP Synthesis Topic 26-05, Long-Term Noise Characteristics of Pavement Surface Texture.

Larson, R.M., and B.O. Hibbs, PCC Surface Texturing Issues, Federal Highway Administration, April 1995, 24 pp.

This paper presents a status report on the FHWA’s re-evaluation of existing PCC surface texture guidelines.  It presents preliminary findings and recommendations from several ongoing studies, including the detriment of poor quality concrete mix designs, drainage and safety considerations that must be taken into account, and alternative surface treatments to improve skid resistance.  Life-cycle cost analysis is also discussed briefly.

Legge, W.A., Slip Form Concrete Pavement Consolidation Study, Kansas Department of Transportation, 1982, 22 pp.

The purpose of this investigation was to determine if consolidation of slip-formed pavement could be improved by alterations to the system normally used on Kansas DOT projects.  Variations in the vibratory system, mix design, and pavement system were evaluated by taking densities with a nuclear meter.  Not all tests were conclusive, but overall results confirmed that consolidation could be improved.

Loeffler, M.D., C.G. Papaleontiou, A.H. Meyers, and D.W. Fowler, "Moisture Retention Tests and Agitation for Membrane-Forming Curing Compounds for Portland Cement Concrete," Transportation Research Record 1110, 1987, pp. 46-59.

Discussed in this paper are the relative merits of Texas specifications (Tex-219-F) and ASTM specifications (ASTM C 156-80) for testing moisture retention by liquid membrane-forming curing compounds.  A comparison is also presented of the effectiveness of four motorized agitation devices to be used through drum bungholes.   Preliminary work toward the development of a new moisture retention test to replace Tex-219-F and ASTM C 156-80 is also outlined, in addition to suggestions for the direction of continuing research.  Recommendations are presented concerning the 6-month curing compound shelf life in effect at the time of the study and the possibility of extending this shelf life.  Research is also reported on the effects of altering application rates and pattern on moisture retention.  In addition, the use of optical reflectance as a measure of application rate is examined.  Finally, findings are presented on the usefulness of in-line testing samples as compared with the usefulness of samples from store drums.

Loo, K., and D.A. Lange, Evaluation of Potential Applications of End-Result and Performance-Related Specifications, White Paper Presentations—Part II, Chapter VI—Structural Concrete, Publication No. FHWA-IL-UI-257, Illinois State Department of Transportation, December 1995, 72 pp.

The primary objective of this study is to evaluate, based on the best available technology, the potential applications of end-result specifications (ERS) and performance-related specifications (PRS) to asphalt concrete paving, portland cement concrete paving, and structural concrete construction.  For each area, the following tasks were performed:

• Review of current literature on ERS and PRS.

• Comprehensive evaluation of other State practices to include parameters used, lot size, and payment schedules.

• Review and evaluation of current Illinois DOT specifications, practices, and policies.

• Identification of relevant IDOT data that have potential application.

• Evaluation of the feasibility of relating materials and construction data to facility performance.

• Determination of the quality of available data and their appropriateness for data analysis.

• Statistical analysis of selected variables within available data and determination of their suitability for developing ERS and PRS.

The study is organized into two parts.  Part I discusses the basic concepts and development of ERS and PRS, and quality acceptance plans.  Part II discusses the framework of ERS and PRS, current practice, and data analyses for each of the three areas studied.  The report also contains a literature review, summary of other State practices, review and evaluation of the IDOT specification, analyses of MISTIC data, potential linking of MISTIC and Illinois Pavement Feedback System data, and recommendations for improvements to current QC/QA specifications for structural concrete construction.

Magura, D., and G. Crawford, "New Concrete Test Device a Fresh Idea," Roads & Bridges, October 1995, p. 12.

This article describes the air void analyzer (AVA).  Developed in Denmark in the early 1990’s, the AVA tests a sample of fresh concrete to determine the amount of air voids and the spacing between them.  This allows agencies to test trial mixes in the laboratory, as well as to provide quick feedback during construction.  Being able to compare test results before and after placement will allow for an improved quality assurance program with a better measure of entrained air.

Mahone, D.C., K.H. McGhee, J.G.G. McGee, and J.E. Galloway, "Texturing New Concrete Pavements," Transportation Research Record 652, Transportation Research Board, 1977, pp. 1-10.

Several texturing experiments on heavily traveled portland cement concrete pavements in Virginia are described.  Included in the experiments were textures imparted by using a heavy burlap drag, metal tines (transverse and longitudinal striations), sprinkled aggregate, mortar removal, and imprinting.  All textures were imparted to concrete in the plastic state.  Some of the problems encountered in achieving the desired textures are discussed.  Evaluations of the effectiveness and the acceptability of the textures included noise, roughness, and skid-resistance studies.  These studies resulted in the rejection of several textures for future use for one or more reasons.   Consideration of all factors gave strong indication that transversely tined grooves spaced 19 mm (0.75 in) apart (center-to-center) would be preferable on tangent roadway sections, whereas longitudinally tined grooves spaced 19 mm apart in combination with transverse grooves spaced 76 mm (3 in) apart would be preferable on curves.

Majidzadeh, K., and G.J. Ilves, Correlation of Quality Control Criteria and Performance of PCC Pavements, Publication No. FHWA-RD-83-014, Federal Highway Administration, March 1984, 147 pp.

This report summarizes the results of a study of the interrelationships between quality indicators and performance of PCC pavements.  Historical and construction data relative to selected quality variables were collected for 104 concrete pavement projects in 5 States.  These projects were then subjected to a pavement condition evaluation.   A number of statistical analyses were performed to establish relationships between the performance rating and the quality indicator data, and 55 models were developed and tested.  The report illustrates the types of performance and quality indicator data required to develop statistically reliable relationships, the types of results that can be obtained from such analyses, and the impact of missing data on model development and reliability.

Majidzadeh, K., G.J. Ilves, M. Luther, and P. Kopac, "Correlation of Quality-Control Data and Performance of PCC Pavements," Transportation Research Record 924, Transportation Research Board, 1983, pp. 93-99.

The relationship between concrete pavement quality indicators and pavement performance is presented.  A literature review was conducted to help identify pavement quality indicators, such as water/cement ratio, strength, slump, air content, and so forth.   A detailed field investigation was carried out in five States to collect quality indicator data.  A pavement condition rating (PCR) procedure was developed to collect PCR data for various pavement sections.  Linear and nonlinear statistical analyses were conducted to develop models relating quality control data with PCR data.  The results of the statistical analyses and the nature of the models developed are discussed in detail.

Marquart, M., Evaluation of Tining Widths to Reduce Noise of Concrete Roadways, Experimental Study No. ND-94-09, North Dakota Department of Transportation, February 1995, 17 pp.

The object of this experimental project is to evaluate the effectiveness of various tining widths to reduce noise.  This study is expected to provide the NDDOT with the quietest and safest tining spacing for its concrete highways.

Mattaacchione, A., and L. Mattacchione, "Correlation Between 28-Day Strength and Density," Concrete International, March 1995, pp. 37-41.

This article discusses the relationship between 28-day concrete strength and concrete density as studied during construction of a housing project.  The authors found that many factors that have long been thought to be useful indicators actually have very low correlations with 28-day strength.  For example, although the 28-day strength generally increased as the water-to-cement (w/c) ratio decreased, the large variability in the 28-day strength for any w/c ratio showed this factor to be, in itself, an unreliable predictor of concrete strength.  However, a significant correlation was shown between 28-day strength and concrete density, and the authors suggest that density may be a useful indicator of potentially low 28-day concrete strengths.

McBride, J.C., Predicting the 28-Day Strength of Portland Cement Concrete by Nuclear Densities, Final Report, Publication No. UDOT-MIR-77-1, Utah Department of Transportation, Materials and Research Section, November 1976, 31 pp.

The report covers a preliminary investigation into the possible use of concrete nuclear densities as a substitute for 28-day concrete specifications.  During the investigation, five variables (slump, entrained air, cylinder strength, core strength, and nuclear density) from three previously constructed concrete pavement projects were evaluated.  The evaluation indicated a high correlation between cylinder strength, core strength, and nuclear density.  The confidence limits were too great to allow nuclear density readings to replace the 28-day cylinder strength requirements.  The study recommended further research to incorporate a density requirement as a construction control of consolidation and not of concrete strength.

McCullough, B.F., D. Zollinger, and B.T. Allison, Preliminary Research Findings on the Effect of Coarse Aggregate on the Performance of Portland Cement Concrete Paving, Publication No. FHWA-TX-94-1244-5, Federal Highway Administration, Texas Department of Transportation, October 1993, 112 pp.

This report focuses on aggregates used in the construction of continuously reinforced concrete pavements (CRCP).  Specific chapters address past research regarding aggregates used in asphalt concrete paving, field and laboratory investigations of asphalt concrete pavements, and CRCP behavior and distress.  Also addressed are research activities related to aggregates used in asphalt cement concrete pavements.  The report reviews such topics as spalling and punchout distresses in continuously reinforced and jointed pavements, aggregate shape characterization using fractals, and the determination of sawcut depth using fractal analysis.  Some of these activities relate directly to improving pavement performance, regardless of aggregate type used for construction.  Early recommendations based on the project’s significant findings have already been presented to the Texas Department of Transportation.

McFarland, W.F., Benefit Analysis for Pavement Design Systems, Research Publication No. 123-13, Texas Highway Department, April 1972, 88 pp.

The Texas Pavement Design System of the Texas Highway Department includes computer programs that compare pavement design strategies on the basis of effectiveness and cost.   The effectiveness of pavements is measured primarily by the pavement serviceability index.  This report presents an investigation to determine whether motorist benefits can be related to the pavement serviceability index and whether these benefits can be used in the comparison of pavement design strategies.  The motorist benefits that are considered are those associated with travel time, vehicle operating costs, accident costs, and discomfort.  A model for relating motorist benefits to the pavement serviceability index is presented, and preliminary estimates of benefits are developed.

McMahon, T.F., W.J. Halstead, W.W. Baker, E.C. Granley, and J.A. Kelly, Quality Assurance in Highway Construction, Publication No. FHWA-TS-89-038, Federal Highway Administration, October 1990, 70 pp.

This report contains reprints of six articles on the subject of quality assurance that have appeared in past issues of Public Roads magazine.  The articles are divided into the following:

• Introduction and Concepts
• Quality Assurance of Embankments and Base Courses
• Quality Assurance of Portland Cement Concrete
• Variations of Bituminous Construction
• Summary of Research for Quality Assurance of Aggregate
• Control Charts

Meininger, R.C., F.T. Wagner, and K.W. Hall, "Concrete Core Strength—The Effect of Length-to-Diameter Ratio," Journal of Testing and Evaluation, 5(3).

ASTM C 42-68, Method for Obtaining and Leasing Drilled Cores and Sawed Beams of Concrete, currently contains length-to-diameter ratio correction factors for soaked cores, but not for dried cores.  However, it is widely recognized that for structures that will be substantially dry in service, dried cores are more appropriate.  It is sometimes difficult (because of constraints of aggregate size, reinforcing bar placement, and member dimensions) to obtain drilled cores of the preferred dimensions, with a length twice the diameter.  Data were collected in two laboratories by drilling and testing a large number of 4-in (102-mm) diameter soaked and dried cores with length-to-diameter ratios of 1.0, 1.25, 1.5, 1.75, and 2.0, taken from six structural-size members.   Research results indicated that the same correction factors can be used for both moisture conditions and that the factors now in ASTM Method C 42-68 should be lowered slightly.  In addition, data were gathered on the effect of the end preparation procedure on core strength.  For the methods used (three capping procedures and grinding of the ends), no important differences in measured strength were noted.

Mitchell, M.F., C.J. Semmelink, and A.L. McQueen, "Statistical Quality Assurance in Highway Engineering in South Africa," Transportation Research Record 652, Transportation Research Board, 1977, pp. 58-65.

This paper examines the first large-scale application of process and acceptance control plans to a major road construction project in South Africa.  The acceptance control scheme used and its background are outlined, and certain controversial features of the scheme are discussed.  The variability of typical South African construction materials and processes is indicated.  Some economic consequences of the use of the plan are also reported.  Because the average quality of the work was well above the minimum standard required, a fully conclusive assessment of the financial advantages or disadvantages of the scheme is not possible.  Because of this, a comparison was made between the acceptance decisions of the specific scheme discussed, and those of the engineering judgment approach.  It is concluded that the use of the statistical method leads to more consistent interpretation of results, and the continued use of this scheme on highway projects is recommended.

Moody, E.D., "PCCP Performance Trends Based on LTPP Program GPS Data," Prepared for the 1996 Region 8 Concrete Pavement Workshop, Salt Lake City, Utah, February 1996, 8 pp.

This project focuses on a subset of the LTPP database related to the primary traffic and environmentally induced distresses that occur in all PCC pavements (JPCP, JRCP, and CRCP), as well as roughness (IRI).  The objective of the project is to utilize the LTPP data to:

• Develop statistical models to predict the primary distresses that occur in PCC pavements (cracking, faulting, and spalling).

• Develop statistical models to predict changes in IRI.

• Evaluate existing and develop new mechanistic-empirical models for predicting the occurrence of distress in PCC pavements.

This work identifies numerous preliminary findings related to both PCC pavement distresses and roughness measurements.  These preliminary findings may necessitate some changes in the approach to analyzing data, as well as the nature of future models used in pavement design.  This presentation also addresses some of the unique characteristics of the LTPP PCC pavement data.

Muenow, R., "A Sonic Method to Determine Pavement Thickness," Journal of the PCA Research and Development Laboratories, 5, No. 3, Portland Cement Association, September 1963, pp. 8-21.

This paper presents the theoretical and practical aspects of a technique for determining the thickness of concrete slabs by nondestructive means.  The longitudinal resonant frequency wavelength, which is equal to twice the thickness, can be determined from values of pulse velocity and resonant frequency.  The data indicate that the difference between the nondestructive determination and the thickness as measured on one core is approximately 5 percent for any one point on the slab, and between 2 and 3 percent if a number of comparisons are made along the slab.  Surface cracks, other defects, and construction features may, however, increase the differences.

Nagi, M.A., and D.A. Whiting, "Achieving and Verifying Air Content in Concrete," PCA R&D Serial No. 1975, Portland Cement Association, 1994, 76 pp.

The objective of this research program was to resolve discrepancies in measurement of concrete air content between fresh and hardened states.  In the first phase, data related to air content measurement were collected.  A database was developed using studies where air contents were determined in the fresh and hardened states on the same batches of concrete.  A questionnaire was also circulated in order to gather information from practical applications.  In the second phase, a laboratory investigation was conducted to evaluate the effects of air-entraining admixture, cement alkali level, temperature, and retempering on changes in concrete air contents between fresh and hardened states.  Following the completion of Phase II, a field-simulation study was conducted in order to examine the influence of field conditions on air content measurements.  A statistical analysis was conducted to define the significance of each factor affecting air content measurements.

This study indicated that none of the factors evaluated have a significant effect on air content discrepancy.  Although air content of hardened concrete may differ from air content of fresh concrete measured with the pressure meter, in most cases, these differences are insignificant.

Neal, B.F., An Evaluation of PCC Pavement Tine Texturing Patterns, Interim Report, Publication No. FHWA/CA/TL-85/05;54-633366, California Department of Transportation, November 1985, 22 pp.

This report provides a limited comparison of transverse and longitudinal tine texturing of PCC pavements.  Skid test results and accident data are provided and analyzed.   The advantages and disadvantages of each method and the reasons for California's adoption of the longitudinal tining procedure are discussed.  It is concluded that although the skid values of transverse textured surfaces are slightly higher than those textured longitudinally, both types perform satisfactorily.  Thus, because of the lower cost, it is recommended that longitudinal tining continue to be specified by Caltrans.

Neaman, D., and J.G. Laguros, "Statistical Quality Control in Portland Cement Concrete Pavements," Transportation Research Record 184, Transportation Research Board, 1967, pp. 1-12.

Quality control of PCC pavements and their component parts was statistically studied in a field project approximately 8 mi (12.9 km) long.  Standard field tests on fresh concrete and standard laboratory tests on hardened concrete, coarse and fine aggregate, and cement were run on an adequate number of samples.  Ninety-five pavement thickness measurements were taken, and 400 concrete cylinders were tested.  For other characteristics, such as slump, air content, gradations, durability, Los Angeles loss, sand equivalent, fineness, and percent passing the No. 200 sieve, 200 observations were made.  The typical statistical parameters (testing, sampling and material variances, standard deviation, and arithmetic mean) were calculated, and frequency distribution curves were drawn.

In nearly all cases, the arithmetic mean of the measured characteristic complied well with the specifications.  However, the relatively high values of standard deviation and of the testing variance raise serious questions about the philosophy underlying the existing acceptance–rejection procedures in PCC pavements.  Upper and lower control limits, especially those based on average values, show conclusively that unfit material is sometimes accepted.  Also, large values of the testing variance s _t suggest that standard tests need some refinement, if not a complete modification, to reduce their inherent variance.

Neville, A. "Is Our Research Likely to Improve Concrete?" Concrete International, March 1995, pp. 45-47.

This editorial criticizes concrete research as a whole, as well as the ways in which that research is incorporated into practice.  According to the author, many research projects are necessarily confined to studying the effects of changing one or two variables at a time using a very limited range of concrete materials, and are often conducted at room temperature.  However, because real-life conditions seldom conform to these conditions, it is very difficult to make useful generalizations based on the aggregation of these research projects.  Moreover, there is real danger that the conclusions drawn from this type of research may become embedded in the literature as if they were generally valid.

Okamoto, P.A., C.L. Wu, S.M. Tarr, M.I. Darter, and K.D. Smith, Performance-Related Specifications for Concrete Pavements, Volume III: Appendix D—Laboratory Testing Procedures and Testing Results and Appendix E—Review of Recent Studies and Specifications, Final Report, Publication No. FHWA-RD-93-044, November 1993, 143 pp.

Drawing upon previous work, a prototype PRS was developed that considers the expected life-cycle cost of the as-constructed pavement as the overall measure of quality.   The approach calls for measurement of in situ concrete properties and explicitly considers variability and multiple quality characteristics in the determination of pay adjustments.  Extensive laboratory testing was conducted to determine material relationships needed in the prototype PRS, and a detailed test plan was developed for the evaluation of construction variables (e.g., dowel misalignment) that significantly affect concrete pavement performance, but are not currently accounted for in the specification.   A computer program, PaveSpec, was developed for use with the specification in simulation and in generating pay adjustments.

This volume contains supporting documentation for the research study.  Appendix D describes the laboratory testing that was conducted under this study for use in the development of the prototype PRS.  The various laboratory tests are described, and a summary of the data is included in both tabular and graphical form.  Appendix E contains a summary of several key studies that have been conducted on performance-related specifications and presents a summary of specifications that incorporate PRS concepts to some extent.

Okamoto, P.A., P.J. Nussbaum, and K.D. Smith, "Guideline Recommendations for Timing Contraction Joint Sawing of PCC Highway Pavements," Proceedings: Fifth International Conference on Concrete Pavement Design, Volume 2, Purdue University, April 1993, pp. 39-52.

Timing of contraction joint sawing is essential to avert raveling at sawcut edges and uncontrolled cracking of concrete pavements.  The objectives of this study were to determine the "near" and "far" joint sawcutting window of opportunity and to evaluate nondestructive testing methods and strength indicators that will assist in determining when sawcutting should be initiated.  To determine "near" sawing strength indicators, sawing tests were made on large-scale concrete slabs with different aggregates and cement contents.  Relationships were developed between surface raveling, sawcut acceptance rating, and compressive strength.  Recommended minimum concrete strengths were developed as a function of cement content and aggregate type.  Observations of sawcutting and strength development at several highway projects provided comparisons between laboratory and construction site strength development and sawcut quality.  Restraint axial and curling (bending) stresses were also calculated using early age temperature histories of concrete pavements.   Observations of sawcutting and strength development at several highway projects provided comparisons between construction site strength development and monitoring of crack development below sawcuts.  Early age strength properties developed as part of the laboratory investigation and strengths measured in the field were used with calculated restraint stresses to develop guidelines that can be used to determine the "far" sawcutting limit of opportunity.

Okamoto, P.A., P.J. Nussbaum, K.D. Smith, M.I. Darter, T.P. Wilson, C.L. Wu, and S.D. Tayabji, Guidelines for Timing Contraction Joint Sawing and Earliest Loading for Concrete Pavements, Volume I, Publication No. FHWA-RD-91-079, Federal Highway Administration, February 1994, 292 pp.

A study was conducted to provide guidelines for timing of contraction joint sawcutting to avert uncontrolled pavement cracking and to provide guidelines for early loading of pavements by construction traffic.  A laboratory study of early age (4 to 24 hours) and early pavement loading (1 to 28 days) concrete strength properties for a range of highway concrete mixes was made.  Sawcutting tests were made to determine earliest contraction joint sawcutting.  Earliest sawcut timing was correlated on the basis of sawcut ratings to concrete strength properties and nondestructive test results that can be used to determine earliest sawcutting time.  Concrete pavement placement and joint sawcutting were observed at three highway construction sites to verify test results.   Latest sawcutting time was targeted on the basis of buildup of restraint stresses attributable to slab cooling.  Guidelines for sawcut timing are presented to facilitate construction site decision-making based on nondestructive test methods.   Early loading by construction traffic was analyzed using ILLI-SLAB finite element models.  Load tests were made at two pavement sites to verify that analytical model results are applicable to new pavements.  Guidelines are presented to facilitate construction site decision-making for early trafficking of new pavements based on nondestructive test methods.

Okamoto, P.A., P.J. Nussbaum, K.D. Smith, M.I. Darter, T.P. Wilson, C.L. Wu, and S.D. Tayabji, Guidelines for Timing Contraction Joint Sawing and Earliest Loading for Concrete Pavements, Volume II: Appendix, Publication No. FHWA-RD-91-080, Federal Highway Administration, February 1994, 224 pp.

This is the second volume of the report described above.  It contains the appendixes to the final report.

Okamoto, P.A., "Field Evaluation of Dowel Placement Along a Section of Interstate 45 in Texas," Transportation Research Record 1186, Transportation Research Board, 1988, pp. 16-34.

This report presents the results of a field investigation conducted to determine the effectiveness of an automatic dowel bar inserter at properly placing dowel bars in rigid pavements.  The study, which was sponsored by the FHWA Demonstration Projects Division, was conducted during February and March 1987 along a section of I-45, south of Dallas, Texas.  A commercially available radar system, capable of quickly and easily locating reinforcing bars and other embedded steel in concrete, was used to examine the experimental dowel placement.  This system produces a real-time graphic recording that gives both location and relative depth of the embedded steel.  Cores were taken to calibrate the graphic recordings so that the actual embedded depths of the steel bars could be obtained.  Along one portion of the test section, a dowel bar inserter was used to place dowel bars in the plastic concrete.  For the remainder of the project, dowel basket assemblies were used to place dowels at transverse joints.  The radar system was then used to evaluate dowel placement along 51 basket assembly and 52 inserter joints. Results indicate that dowel bar alignment at inserter joints is as good as or better than that at the basket assembly joints.

Oluokun, F.A., E.G. Burdette, and J.H. Deatherage, "Rates of Development of Physical Properties of Concrete at Early Ages," Transportation Research Record 1284, Transportation Research Board, 1990, pp. 16-22.

This paper presents an investigation into the gain of physical properties of concrete with time and experimental results on the development of compressive strength, splitting tensile strength, modulus of elasticity, and Poisson's ratio.  The results show that the elastic modulus developed much faster than either the tensile or the compressive strength, which developed at approximately the same rate.  Poisson's ratio did not change substantially with either richness of mix or age of concrete and did not vary appreciably with time after 6 h.  The period within the first 12 h after casting was observed to be the period of fastest development of physical properties.

Ozyildirim, C., 4 x 8 Inch Concrete Cylinders Versus 6 x 12 Inch Cylinders, Virginia Highway & Transportation Research Council, May 1984, 25 pp.

Laboratory and field investigations were conducted to compare the compressive strengths obtained for 4- x 8-in (100- x 200-mm) cylinders with those for standard 6- x 12-in (150- x 300-mm) cylinders, both made with aggregate having a nominal maximum size of 1 in (25 mm).  In the laboratory, in addition to the effect of specimen size on strength, factors such as the mold type, aggregate type, and strength level were considered.   The results of the laboratory work indicate that the two sizes of cylinders yield equal compressive strength values at a strength level of about 3,200 psi (22.0 MPa).   Above this level, the small specimen values between the two sizes increase with the strength level.  The standard deviation of strength values was higher for the small specimens.  For equal precision, more tests are needed for the small specimens than for the larger ones.

The field investigation included an examination of the effect of different specimen sizes when different types of mold and capping procedures were used for each size.   The results of the field tests comparing specimen sizes were similar to those of the laboratory tests in terms of strength and variability.  It was concluded that the results of tests on three small cylinders cast in plastic molds and tested with neoprene pads in steel end caps can be used to predict the strengths of A3 and A4 concretes.   The variability of small cylinders compared to that of larger ones prepared in the field was slightly higher, although not statistically significant; therefore, the use of three small cylinders (rather than two larger ones) is recommended.

Parcells, W.H., Jr., and M. Hossain, "Kansas Experience With Smoothness Specifications for Concrete Pavements," Prepared for Transportation Research Board 73rd Annual Meeting, January 1994, 21 pp.

There is a growing interest in the industry in attaining smoother and smoother pavement surfaces.  Smoothness specifications for PCC pavements now in effect in Kansas have evolved through applications over the last 80 years.  Pavement profiles of short wavelengths and smaller amplitudes than the industry-accepted 5.1 mm (0.2 in) can adversely affect the ride quality of pavements.  This experience has led KDOT to eliminate the blanking band width in the profilograph trace reduction process.  The implementation of this "zero" or "null" blanking band was successful and has resulted in better quality pavements.  The latest proposed specifications will increase the amount of bonus that can be achieved, but might result in more grinding unless the PCC pavement pavers were able to improve the pavement smoothness in the middle (full-pay/grind) ranges.  An analysis of the effect of as-constructed smoothness on the roughness history of pavements has shown that the ride quality over the service life of pavements is highly dependent on the smoothness achieved during construction.   Limited cost analysis has shown an increasing amount of bonus achieved in PCC pavement construction over the last few years, indicating quality paving in Kansas.

Parcells, W.H., Jr., Control of Pavement Trueness in Kansas, Interim Report, Kansas Department of Transportation, Bureau of Materials and Research, January 1992.

The smoothness of new pavement has shown significant improvement in the 6 years that the profilograph has been required in Kansas.  Changing to the zero blanking band will allow better measurement of the quality of pavement smoothness with existing equipment in the years to come.

Patel, A.J., M.R. Thompson, and S.H. Carpenter, Evaluation of Potential Applications of End-Result and Performance-Related Specifications, White Paper Presentations—Part II, Chapter IV—Asphalt Concrete Pavements, Publication No. FHWA-IL-UI-255, Illinois Department of Transportation, December 1995, 185 pp.

The primary objective of this study is to evaluate, based on the best available technology, the potential applications of end-result specifications (ERS) and performance-related specifications (PRS) to asphalt concrete paving, portland cement concrete paving, and structural concrete construction.  For each area, the following tasks were performed:

• Review of current literature on ERS and PRS.

• Comprehensive evaluation of other State practices to include parameters used, lot size, and payment schedules.

• Review and evaluation of current Illinois DOT specifications, practices, and policies.

• Identification of relevant IDOT data that have potential application.

• Evaluation of the feasibility of relating materials and construction data to facility performance.

• Determination of the quality of available data and their appropriateness for data analysis.

• Statistical analysis of selected variables within available data and determination of their suitability for developing ERS and PRS.

Part II of this study discusses the framework of ERS and PRS, current practice, and data analyses for each of the three areas studied.  The report also contains a literature review, summary of other State practices, review and evaluation of the IDOT specification, analyses of MISTIC data, potential linking of MISTIC and Illinois Pavement Feedback System data, and recommendations for improvements to current QC/QA specifications for structural concrete construction.

Pechlivanidis, C., C.G. Papaleontiou, A.H. Meyer, and D.W. Fowler, The Effectiveness of Membrane Curing Compounds for Portland Cement Concrete Pavements, Final Report, Publication No. FHWA-TX-89-1118-1F, Texas State Department of Highways & Public Transportation, November 1988, 66 pp.

Membrane curing compounds are widely used to cure concrete in highway construction.   The function of these compounds is to form a membrane that helps retain the moisture in the concrete slab that is otherwise lost through evaporation.  The amount of evaporation loss varies as a function of the environmental conditions and the temperature of the concrete mass during the curing period.  This report provides an evaluation of the performance of membrane curing compounds as related to concrete material properties such as tensile and flexural strength, stiffness, surface durability, and density.  In addition to traditional testing methods, the nondestructive, in situ Spectral Analysis of Surface Waves (SASW) method is also used to observe and measure material properties as a function of time.  Testing can start at initial set or when the modulus of elasticity for concrete is about 10,000 psi (69.0 MPa).

Pitt, J.M., R.A. Carnazzo, J. Vu, and M. Seshadri, Control of Concrete Deterioration Due to Trace Compounds in Deicers, Final Report, Publication No. Iowa DOT Project HR-299, Iowa Department of Transportation, Highway Division, May 1992, 88 pp.

This report contains work on three facets of rock salt deicer action on freeze-thaw resistance of portland cement concrete.  The first deals with improvement of mortars, where it is demonstrated that a 10- to 15-percent replacement of cement with fly ash can more than double the life of concrete by the reduction of porosity and stabilization of calcium hydroxide.  Excessive fly ash was found to counteract this benefit.   Second, this research defines behavior and performance of aggregates displaying different service lives in concrete-subjected deicers.  Freeze-thaw in water produced failure in the aggregate, whereas in deicers, damage was exclusive to the mortar-aggregate interface or the mortar.  Aggregate porosity appeared to be a good, but not infallible, predictor of concrete service life.  Low-porosity aggregates were best.   The third feature of this research was development of a test method capable of modeling the freeze-thaw process and predicting life performance.  This was done by adaptation of the ASTM C 666 test to include a reliability-based design.  Essential to this test method was the objective definition of failure and a realistic model linking laboratory tests to the temperature observed in the field.

The methodology was compared to performance of a pavement in central Iowa.  The model predicted life of 25 years, and the pavement actually failed at 26 years.  This predictive method was also used to contrast the life of a pavement subjected to different deicing materials.

Poblete, M., P. Ceza, J. David, R. Espinosa, A. Garcia, and J. Gonzalez, "Model of Slab Cracking for Portland Cement Concrete Pavements," Transportation Research Record 1307, Transportation Research Board, 1991, pp. 154-161.

A predictive model of slab cracking has been developed by considering the actual behavior of Chile's PCC pavements.  The approach used is mechanistic-empirical and is based on a structural modeling of the jointed pavement using a finite elements program.   The model incorporates realistic boundary conditions of upward concave slabs under yearly cyclic moisture warping and daily cyclic temperature curling obtained from measurements in the climatic zone of central Chile.  Fatigue consumption in the slabs was evaluated for the actual traffic loads passing during each group of hours in each season to determine the different levels of upward concavities.  The accumulated fatigue consumption of all pavements was calculated and plotted against the percentage of cracked slabs observed in the field.  The resulting model is a unique S-shaped curve that is useful for indicating the effect of many design variables on cracking.

Raczon, F., "Pavement Smoothness Goal of PCC Slipform Paving," Roads & Bridges, April 1989, pp. 73-74.

Smoothness has become an important test for PCC pavements in recent years as agencies strive to obtain scientific evidence to support road users’ complaints.   Profilograph measurements and other related technology are becoming more common in end-result specifications, and the demand for pavement smoothness is greater than ever before.  Faced with increased pressure to produce the smoothest pavements possible, slipform paver operators need to balance a variety of factors in order to achieve the desired concrete pavement quality.

Rix, G.J., J.A. Bay, and K.H. Stokoe II, "Assessing In Situ Stiffness of Curing Portland Cement Concrete With Seismic Test," Transportation Research Record 1284, Transportation Research Board, 1990, pp. 8-15.

In situ measurement of surface-wave velocity using the Spectral Analysis of Surface Waves (SASW) method shows that this type of seismic measurement offers a reliable alternative to conventional penetration resistance and cylinder compression testing for determining the stiffness of PCC during curing.  Both surface-wave velocity and penetration resistance exhibit similar rates of increase during the initial stages of curing, suggesting that in situ measurements of wave velocity are potentially useful for assessing the degree of curing that has occurred.  At later stages of curing, values of Young's moduli calculated from in situ seismic tests agree well with values of Young's moduli from cylinder compression tests for similar curing histories.  Advantages of seismic tests such as the SASW test are that unlike penetration resistance and cylinder compression tests, they: (1) require no samples, (2) can be performed directly on the concrete slab to evaluate spatial variability, and (3) can be performed repeatedly at the same locations at different times during the curing process.

Ross, F.R., and T.S. Rutkowski, A Designed System of Load Transfer Dowels for Joints in PCC Pavement, Final Report, Applied Research Section C.O. Materials, Division of Highways and Transportation Services, Wisconsin Department of Transportation, January 1989, 40 pp.

The intent of the research was to determine the need for load transfer dowels at contraction joints in plain concrete pavement on moderately loaded facilities (10,000 average daily traffic [ADT] and 10 to 14 percent heavy vehicles), as well as to determine if a modified dowel system with a reduced amount of steel is an adequate replacement for the standard Wisconsin dowel system.  A plain concrete pavement was built containing three separate test sections, intended to represent three levels of cost. Section A had skewed, random-spaced contraction joints with no load transfer dowels.  Section B had right-angle joints spaced at 20 ft (6.1 m), with the modified dowel system.  Section C was similar to B except that it had the standard dowel system.

Measurements were made of initial horizontal and vertical dowel alignment, and periodic monitoring of load transfer efficiency (LTE), pavement serviceability index (PSI), pavement distress, seasonal horizontal joint movement, and faulting was performed.   Pavement temperature, joint width, and load transfer efficiency were related.   The LTE drops sharply for joint openings greater than 0.040 in (1.0 mm), which occurs at slab temperatures less than 75 °F (23.9 °C). At 32 °F (0.0 °C), the LTE of doweled joints is 95 percent compared to 75 percent for non-doweled joints.  The measured LTE of non-doweled transverse joints was significantly less than that of doweled transverse joints.  The modified dowel design had an incidence of faulting equal to that of the standard dowel system and significantly less than the non-doweled system in both quantity and severity.   Undoweled joints have a 60-percent probability of developing faulting, compared to 15 percent for doweled joints.  The modified dowel section had less spalling than the other two sections and a relatively equal incidence of cracking; the severity of these characteristics could not be attributed to the presence of lack of joint transfer.   The present serviceability index (PSI) of the three test sections has remained relatively equal over the 12-year life of the pavement and has not approached the traditional threshold value at which rehabilitation actions would be considered.

None of the measured characteristics had an apparent effect on the pavement performance.  It is recommended that moderately loaded pavements be constructed with non-doweled, random skewed, plain pavement systems, or modified dowel systems using joint spacings of 30 ft (9.1 m) or greater.

Roy, D.M., Concrete Microstructure, Quarterly Report, Strategic Highway Research Program, July 1989.

This report delineates curing conditions with potential risk of damage to the concrete.   For concrete mixtures where sulfate-resistant cement is used, no curing problem will occur if concrete temperatures are between 50 and 80 ° F (10.0 and 26.7 °C) and constant air temperatures are between freezing and 100 ° F (37.8 °C).  For concrete mixtures with ordinary portland cement, the problem-free curing conditions are similar.  As expected, the safe intervals for concrete mixtures using hardening cement are smaller; for mixtures with up to 620 lb/yd³ (367.8 kg/m³) of concrete, temperatures between 40 and 80 ° F (4.4 and 26.7 °C) and air temperatures between 40 and 100 ° F (4.4 and 37.8 °C) are required.

Sandberg, U., "Mobile Contactless Profiling of Road Texture Saves Time and Money," Selcom, Swedish Road and Transport Research Institute, 1995.

This short article discusses the development and probable approval of a standardized method for determination of pavement surface texture.  At the same time, PIARC was conducting an experiment to compare texture measurement devices and to ascertain whether texture values can help to clarify frictional characteristics of the pavement/tire interaction.  The results showed that the texture measuring devices correlated well with each other, and some correlated well with friction.

Saraf, C.L., and B.F. McCullough, "Controlling Longitudinal Cracking in Concrete Pavements," Transportation Research Record 1043, Transportation Research Board, 1985, pp. 8-13.

The objective of the study reported in this paper was to investigate the development of longitudinal cracks in wide concrete pavements (two or more lanes in one direction) and to develop a model to estimate the depth of sawcut needed to control these cracks within the groove.  The model developed uses the concepts of variability in the material properties of the concrete (tensile strength), pavement thickness (as constructed in the field), and depth of sawcut groove.  It was observed that estimates of longitudinal cracking have a reasonable match with field observations.  It was observed that the longitudinal cracking of concrete pavements (two or more lanes in one direction) was dependent on the type of aggregate used in the concrete mix.  Two types of aggregates were investigated.  Uniformity of concrete mix strength (tensile) represented by standard deviation (tensile strength) affected the development of longitudinal cracks.   A lower value of standard deviation obtained using lime rock aggregate in the mix was responsible for confining more cracks within the sawcut compared with the mix using river gravel aggregate.  A sensitivity analysis of the model indicated that a substantial reduction in sawcut depth can be achieved if the variability of concrete strength during construction can be reduced.

Sayers, M.W., "Profiles of Roughness," Transportation Research Record 1260, Transportation Research Board, 1990, pp. 106-110.

Road roughness is normally characterized by a summary index that applies over a length of road.  Summary index measures are obtained most directly by measuring the longitudinal profile and then applying a mathematical analysis to reduce the profile to the roughness statistic.  The moving average smoothing filter can be used to obtain a profile of one such roughness measure—the international roughness index (IRI).   The roughness profile provides another dimension to the description of roughness, showing with maximum detail how the roughness is distributed over the length of the road.   The base length used for IRI averaging must be considered.  Specifying the base length becomes particularly important when specifications for road quality are formulated, or when profiling accuracy is prescribed.  When reporting instrument accuracy or writing roughness specifications, it should be taken into account that the variation in IRI found over the length of a road is more extreme when the base length is short.  Specifically, the accuracy of high-speed profiling systems should be specified according to base length.

Schrader, E.K., "A Solution to Cracking and Stresses Caused by Dowels and Tie Bars," Concrete International, 13(7): 40-45.

This report discusses using square dowel bars with a clip-on plastic sheath having compressible material on its sides as a solution to cracking and stresses caused by dowels and tie bars.  The use of square bars instead of round bars provides total vertical load transfer while allowing a compressible material to be attached to the side of the bar.  By using the clip-on sheaths, as a joint opens, the side material simply compresses rather than forcing the bar to bend.  Square bars also provide more resistance to bending, so they provide more resistance to edge and corner curling for the same amount of steel.  By using square bars, the tensile splitting stresses in a slab induced by round bars are avoided.  Square dowels may be used as tie bars if they are altered to resist pullout.  Corrosion protection is also improved by using the plastic sheaths.

Scofield, L.A., Profilograph Limitations, Correlations, and Calibration Criteria for Effective Performance-Based Specifications, NCHRP Project 20-7, National Cooperative Highway Research Program, 1993.

The purpose of this study was to assess the state of the practice in the use of profilographs for measurement of pavement smoothness.  The critical objectives were to evaluate the nature and extent of problems and to recommend research to accomplish solutions to these problems.  A survey of States and industry identified problems and determined the state of the practice.  A literature search was performed, and a limited analysis of the automated profilograph filters was conducted.

The results of the survey indicated that 90 percent of the respondents believe that smoother pavements reduce life-cycle costs and that smoothness requirements will increase in the future.  Currently, the majority of the States use the profilograph for acceptance of pavement smoothness.  Approximately 25 percent of the profilographs used by the States are computerized.  The five highest ranked problems, as reported in the State survey, include comparing profilographs to other roughness measurement devices, trace reduction repeatability, effect of short wavelengths on profile index, interpretations of profilograph traces, and production rate of testing.

The literature search revealed that the variability of mechanical profilographs increases with pavement roughness.  The variability of the computerized profilographs is constant and typically ranges between a standard deviation of 0.5 to 1.0 in/mi (7.9 to 15.8 mm/km).  For pavement roughness levels below 5 in/mi (78.9 mm/km), the mechanical and computerized profilographs exhibited similar variability.  The variability of mechanical profilographs is attributable to trace reduction.  High degrees of correlation exist between mechanical and computerized profilograph test results.  While Ames and California-style profilographs produce similar results, Rainhart and California-style profilographs often do not.

The results of this study indicate a strong need to develop national standards for both the mechanical and computerized test procedures.

Scofield, L.A., S.A. Kalevela, and M.R. Anderson, "Evaluation of California Profilograph," Transportation Research Record 1348, Transportation Research Board, 1992, pp. 1-7.

The Arizona DOT evaluates PCC pavements by testing with mechanical as well as electronic profilographs.  The precision of the two types of profilograph was evaluated. More than 100 profilograph runs were conducted on a selected pavement section.   The range of replicate readings of pavement profile index could be as much as 2.0 in/mi (31.6 mm/km) for a rough pavement.  Electronic profilographs adjusted to operate at low filter settings gave lower profile index values than those obtained with the same profilographs at higher filter settings.

Scofield, L.A., S.A. Kalevela, M.R. Anderson, and A. Hossain, A Half Century With the California Profilograph, Publication No. FHWA-AZ-SP9102, Federal Highway Administration, February 1992, 58 pp.

This study was performed to establish equipment and operator variability for mechanical and computerized California profilographs.  Future work, based on testing conducted during this study, should develop precision and bias statements for profilographs.

The research consists of two phases.  Phase 1 included a literature review, field testing, and statistical analysis.  The historical development of the profilograph and California test procedures and specifications were evaluated in relationship to today’s incentive/disincentive specifications.  Additionally, equipment parameters that influence test variability were reviewed.

Segner, E.P., Jr., and J.R. Cobb, A Study of Misaligned Dowels in Concrete Pavements, HPR Report 32, Alabama Highway Department, August 1967, pp. 1-42.

The primary objectives of this report were to study the effects of misaligned dowel bars across transverse contraction joints in concrete pavement and to determine the maximum dowel bar alignment error that can be tolerated without seriously impairing the effectiveness of the joint.  The conclusions in this report are based on results obtained from testing simulated concrete pavement specimens containing dowel bars aligned with various alignment errors.

Semenov, V.A., "Quality Control in Highway Construction and Maintenance When the Measurement Parameters Are Highly Nonuniform," Transportation Research Record 1126, Transportation Research Board, 1987, pp. 28-36.

In this paper, an original method is presented for quality control based on Weibull's law for the distribution of random quantities with variable parameters.  The nomographs obtained for determining the extremal values of the parameters and the defectiveness index can be used for various cases in the statistical reduction of research results.  The proposed method can be used for quality control for both highly uniform data (in the United States, the measured values are assumed to have a normal distribution for this purpose) and highly nonuniform data.  The method described was widely used in the Soviet Union for quality control in the construction and maintenance of roads.

Sharaf, E.A., M.Y. Shahin, and K.C. Sinha, "Analysis of the Effect of Deferring Pavement Maintenance," Transportation Research Record 1205, Transportation Research Board, 1988, pp. 29-35.

This paper presents a methodology for quantifying increased maintenance and rehabilitation (M&R) costs due to delaying M&R action.  The methodology used data collected from several U.S. Army installations.  These data included: (1) pavement performance measured in terms of the Pavement Condition Index (PCI), (2) structural history, and (3) detailed costs.  The methodology is based on applying life-cycle cost analysis to determine the Equivalent Uniform Annual Cost (EUAC) for various M&R alternatives. This was repeated at different pavement condition levels.   The EUAC analysis for each M&R alternative included pavement surface preparation cost, initial cost of the M&R alternative, and future annual routine maintenance cost.  The results of this study showed that considerable savings can be achieved if pavement sections are maintained while they are in good condition and are not allowed to deteriorate into poor condition.

Shook, J.F., and M.A. Diaz, Performance-Related Specifications for Asphalt Concrete—Phase II, Proposed Plans for Accelerated Pavement Test Track Study, Publication No. FHWA-RD-91-071, Federal Highway Administration, January 1992, 62 pp.

The plan for an accelerated pavement test track study described in this report is part of a Federal Highway Administration (FHWA) program to develop PRS for an asphalt concrete pavement construction by: (1) conducting laboratory studies of the relationships between materials and construction (M&C) variables and fundamental response variables, as well as the response variables and pavement performance indicators, and (2) developing a detailed plan (experimental design, construction details, and data collection and analysis) for an accelerated field test at a test track facility.  The objectives of the accelerated field experiment are:

• To verify (or modify, if necessary) the prediction equations developed in the laboratory phase of the project, "Performance-Related Specifications for Asphalt Concrete—Phase II," under realistic field conditions.

• To relate the predicted performance of test sections obtained from the equations to actual performance defined by pavement ride quality, or distress observed on the test sections when subjected to real traffic and environmental conditions.

• To develop data that can be used to extend the findings to traffic and environmental conditions not included in the original study.

• To develop data that can be used to extend the findings to materials not included in the original study.

• To develop data that may be used to confirm or modify existing relationships between mixture properties and pavement performance variables.

• To use and test, during construction of the facility, the applicability of methods for determining pay factors.

Shook, J.F., M.A. Diaz, M. Stroup-Gardiner, and S.B. Seeds, Performance-Related Specifications for Asphalt Concrete—Phase II, Publication No. FHWA-RD-91-070, Federal Highway Administration, January 1992, 230 pp.

The laboratory study performed for this research project focused on the development of secondary prediction relationships, which are equations that establish the relationship between M&C variables and fundamental response variables.  The results of the laboratory study indicate that compaction level had more influence on mixture properties than any other variable in the experiment.  A technique for estimating compaction effects using measurable specimen properties was found and resulted in a compaction index equation.  The prediction equations can be used with an estimated compaction index to relate measured mixture properties to optimum properties.  These equations can also be used to predict relative effects of proposed changes in materials and construction specifications on performance-related mixture properties.  When used with equations that relate performance-related mixture properties to pavement performance, the equations derived in this study can be used to establish penalties for non-conformance to specification limits.  An automated version (Lotus 1-2-3 spreadsheet) of the conceptual PRS system is included.

Sipherd, C., "The Role of Internal Vibration and the Extrusion Process Slipform Paver in Consolidation: Portland Cement Concrete Pavement Construction," Prepared for Transportation Research Board Annual Meeting, January 1995, 21 pp.

These presentation notes provide practical recommendations for construction using slipform paving and internal vibration.

Smith, G.L., and B.R. McWaters, "Partnering for Performance—Iowa's Experience With Design and Construction Enhancements for Quality Improvement of Concrete Pavements," Transportation Research Record 1478, Transportation Research Board, 1995, pp. 62-66.

Partnering is a new paradigm for owner and contractor relations that emphasizes up-front team building, a clear definition of common objectives, synchronized customs for rapid issue resolution, and joint evaluation of partnership effectiveness.   Construction partnering has existed in a limited form for years, but such relationships have found some difficulty in a system in which the low bidder wins the contract, the taxpayer dollar is at stake, and the government may be sensitive to criticism of not spending the money wisely.  Today, new partnering concepts to protect the public interest have been developed by contracting authority and contractor alliances with both parties.  Most partnering has been between a contracting authority and contractor with a mutual intent to construct a specific project.  This paper describes a more general partnership among the Iowa DOT, other Iowa contracting authorities, and the Iowa Concrete Paving Association. In 1992, Iowa contracting agencies and the concrete paving industry began an Iowa initiative for continuing quality improvement of concrete pavements.  Through the Iowa partnership, changes have been made in standard designs, specifications, materials use, and construction techniques to enhance concrete pavement quality.

Snell, L.M., "Assessing Concrete Technicians," Concrete International, March 1995, pp. 42-44.

The quality of testing is dependent on the ability of the technician.  Managers should use an established procedure to assess technicians and determine if problems are likely to occur.  The procedures described in this paper present a methodology for identifying testing problems and allow mangers to identify if a technician needs to improve testing procedures.  This procedure can help to improve the overall testing and provide positive feedback so that a technician and testing laboratory can assess and improve testing services.

Soriano, A., Dowel Bar Placement and Displacement, Publication No. SK91-09-X, South Dakota Department of Transportation, March 1995, 26 pp.

This report describes research performed by the SDDOT to investigate the problem of dowel bar misalignment in PCC pavements.  More than 400 dowel bars from three construction projects were inspected and compared to the dowel bar alignment specifications.  This study found that the dowel bars tended to conform to the alignment specifications even though, in the opinion of the researcher, the specifications were too rigid.  It was noted that sawing of the contraction joint was the governing factor for the longitudinal displacements.  Although no pavement distress was observed in areas containing dowel bar misalignments, it should be noted that only 2 years had elapsed between project construction and the field survey.  It is the opinion of the researcher that this is insufficient time for pavement distress to manifest itself, since even undoweled PCC pavement may not show distress for 5 years or more.

Steele, G.W., S.B. Hudson, and C.J. Van Til, "The Statistical Approach to Realistic Highway Specifications," Prepared for 25th Annual Convention of SASHO, September 1996, 25 pp.

This paper presents the step-by-step procedure whereby statistical concepts are employed to incorporate statistical parameters, based on West Virginia research data, into specification text.  Numerous figures, flowcharts, and tables are used to illustrate the procedures and to demonstrate that only knowledge of arithmetic is needed to design an acceptance plan.  The statistical approach is extended to the derivation of a penalty system that will permit acceptance of marginal material at a reduced price on a formal contract basis.

Strauss, P.J., and M.F. Mitchell, "The Performance of Jointed Concrete Pavements as Affected by Factors Other Than Traffic-Induced Stress," Proceedings: Fourth International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, Publication No. FHWA-RD-89-208, April 1989, pp. 467-472.

Design and construction techniques developed overseas have been used in Southern Africa on PCC pavements with little variation based on local experience.  This paper describes the methodology by which jointed unreinforced PCC pavements are being evaluated, with the aim of improving local design and construction techniques.  Indications are that failures found on the pavements can often be attributed to inadequate construction techniques and control.  Although the pavements are performing very well, it is felt that an improvement in performance is possible if subgrades are compacted properly to reduce settlement; non-erodible subbases are constructed; load transfer at joints is enhanced by using low-shrinking concrete; joints are kept properly sealed; and PCC-paved shoulders are used.

"Surveying the Many Curing Methods and Materials," Concrete Construction, October 1976, pp. 488-492.

It would be difficult to overemphasize the importance of curing in concrete construction.  The watertightness, hardness, durability, and strength of concrete all depend, to a great extent, on curing practices.  This article presents a short summary of the types and characteristics of curing methods available, including water, burlap, and materials that retain moisture.

Szalay, T.W., "City of Windsor Concrete Pavement Design and Construction Experience," Proceedings: 1991 TAC Annual Conference, Volume 1, 1992.

The City of Windsor has prepared a presentation regarding the culmination of its 25 years of experience in concrete pavement design and construction.  This report highlights the specific features of the equipment utilized and the construction methods used.  The report also features a discussion of state-of-the-art components of concrete pavement technology, such as slipform paving, newer load transfer basket designs, joint spacing and preparation, finishing with trowels and bump-cutter techniques, texturing and curing, sawcutting joints and sealing, profilograph measurements for smoothness, and testing procedures.

Tang, T., D.G. Zollinger, and B.F. McCullough, Field Tests and Analyses of Concrete Pavement in Texarkana and La Porte, Texas, Publication No. FHWA-TX-94-1244-7, Texas Department of Transportation, May 1994, 310 pp.

This report summarizes the research results obtained from two field tests for PCC pavements.  One field test was carried out on test sections of jointed plain concrete pavement in Texarkana, Texas, and the other was carried out on test sections of continuously reinforced concrete pavement in La Porte, Texas.  Laboratory tests and theoretical analysis were also performed to help in understanding and analyzing the field observation.  A closed-form solution is proposed for thermal stresses in a concrete slab when it is curled up.  This solution is for the case where the temperature decrease in the concrete slab exceeds a limit so that a gap forms between the slab and the foundation.  This case was not addressed in the Westergaard solution.  Fracture tests were applied to the concrete made with different coarse aggregates used for Texas pavements and have shown that fracture mechanics is a powerful tool with which to judge the quality of the pavement.  With these efforts, a method based on fracture mechanics is proposed to determine the depth and spacing of the jointed plain concrete pavement.  This method has successfully been applied to the test section in Texarkana.

Tayabji, S.D., "Dowel Placement Tolerances for Concrete Pavements," Transportation Research Record 1062, Transportation Research Board, 1986, pp. 47-54.

The results of an investigation conducted to develop placement tolerances for dowels at concrete pavement joints are presented.  A theoretical analysis of dowel misalignment was attempted.  The purpose of the analysis was to compute restraint stresses induced in the concrete pavement for different levels of dowel misalignment.  However, because of the complexity of correctly incorporating the three-dimensional nature of dowel misalignment, the theoretical analysis was not completed.  The effect of dowel misalignment was then investigated in the laboratory by conducting pullout tests on sections of concrete slabs incorporating a joint and dowels with different levels of misalignment.  Test results indicate that pullout loads were relatively low for dowel misalignment levels of less than 1 in per 18-in (25.4 mm per 457.2-mm) length of dowel bar and a maximum joint opening of 0.25 in (6.4 mm).

Tayabji, S.D., and P.A. Okamoto, "Field Evaluation of Dowel Placement in Concrete Pavements," Transportation Research Record 1110, Transportation Research Board, 1987, pp. 101-109.

Presented in this paper are the results of a laboratory and field investigation conducted to determine the effectiveness of the radar device for evaluating dowel bar misalignment and to evaluate the effectiveness of an automatic dowel bar inserter to properly place dowel bars in rigid pavements.  A commercially available radar system was used.  The system produces a real-time graphic recording that indicates the location and the relative depth of the embedded steel.  Cores are taken to calibrate the graphic recordings to obtain the actual embedded depth of the steel bars.  The laboratory study indicated that dowel bars placed about 5 in (127 mm) below the concrete surface could be located reasonably accurately by the radar system.  In the laboratory, the standard deviation obtained for the differences between actual and measured individual readings was 0.24 in (6.1 mm).  The field evaluation was conducted during June 1986 along a section of Interstate 86 in Idaho.  At this project, an inserter was used to place the dowel bars in the plastic concrete.  Dowel placement along 16 transverse joints was evaluated with the radar system, and results indicate that the radar system can determine the location of dowel bars placed in concrete pavements.  However, the degree of accuracy is operator-dependent and test results must be considered in statistical terms.

Tayabji, S.D., and D. Whiting, "Field Evaluation of Concrete Pavement Consolidation," Transportation Research Record 1110, Transportation Research Board, 1987, pp. 90-100.

Inadequate consolidation of concrete can result in weak concrete that may lead to premature failure or loss of serviceability of the pavement.  Presented in this paper is the result of a comprehensive study on concrete pavement consolidation conducted by Construction Technology Laboratories, Inc., and sponsored by the Federal Highway Administration.  The scope of the work consisted of laboratory testing, evaluation of nuclear gauges, development of model acceptance plans for concrete consolidation, and field implementation of the acceptance plans.  In laboratory tests, consolidation was found to have a strong influence on compressive strength, bond of concrete to reinforcing steel, and permeability of concrete.  There was a lesser effect of consolidation on resistance to freezing and thawing.  A loss of 30 percent was sustained in compressive strength for every 5-percent decrease in consolidation.  A variety of nuclear density gauges was evaluated for use in monitoring consolidation of concrete.   Information was obtained from literature sources and State highway agencies.   Typical precision on field concrete ranges from 1 to 2 lb/ft³ (16 to 32 kg/m³) for most gauge types.  A combination of techniques, such as the consolidation monitoring device and commercial direct transmission gauges, shows promise as a means of monitoring consolidation during the paving process.  A model acceptance sampling plan for concrete consolidation is proposed.  The plan is of the inspection-by-variables type and requires a sample size of eight per lot.  The plan provides for buyer's and seller's risks of 5 percent.  A field trial of a model acceptance plan carried out along a section of I-86 in Idaho indicated that it is practical and cost-effective to monitor concrete consolidation in the field.

Temple, W.H., and S.L. Cumbaa, "Serviceability Index Base for Acceptance of Jointed Concrete Pavements," Transportation Research Record 1196, Transportation Research Board, 1988, pp. 251-256.

This paper describes the techniques and relationships developed to design a Serviceability Index (SI)-based measurement system for acceptance of jointed concrete pavement construction in Louisiana.  Pavement roughness statistics obtained from Mays Ride Meter equipment, a Surface Dynamics Profilometer, and a Chloe Profilometer were regressed to establish an AASHO Road Test-based SI measurement system for concrete pavements with 20-ft (6.1-m) joint spacings (SI JCP 20).  A 1986 panel rating of 25 concrete pavements confirmed the validity of the model.  Field testing of 50 newly constructed concrete pavement test sections provided a relationship between the SI JCP 20 model and profile statistics from rolling profilograph equipment and a 10-ft (3-m) rolling straightedge.  The research resulted in the development of a rational method of providing specification limits for profilograph equipment that relate to pavement rideability.  Specification limits in terms of profile statistics are provided to indicate the quality of paving necessary to construct a jointed concrete pavement with a Serviceability Index of 4.5.

Thompson, M.R., and B.J. Dempsey, Durability Testing of Stabilized Materials, Publication No. UILU-ENG-74-2010, Illinois Department of Transportation, June 1974, 65 pp.

The primary purpose of IHR-401, "Durability Testing of Stabilized Materials," was to develop a satisfactory and realistic procedure for evaluating the freeze-thaw durability of partially cemented highway materials (e.g., soil-cement, lime-flyash-aggregate, lime-soil mixtures).  The following accomplishments were achieved during the project:

Phase 1.  A heat-transfer model was developed and utilized to quantitatively characterize field pavement freeze-thaw conditions for Illinois.

Phase 2.  An automatic freeze-thaw testing apparatus and a test procedure were developed.  An accelerated vacuum saturation test procedure and a cured strength correlation relation were established for predicting freeze-thaw durability properties.

Phase 3.  The equipment, concepts, and procedures established in Phases 1 and 2 were utilized to conduct an extensive laboratory freeze-thaw testing program with typical Illinois stabilized materials.

Phase 4.  A durability evaluation procedure based on the residual strength concept was proposed.  The procedure recognizes three distinct durability zones in Illinois.

Phase 5.  Specific recommended procedures for considering freeze-thaw durability are outlined in the report.

To aid in refining certain aspects of the proposed durability evaluation procedure, some areas will require further investigation (field-mixing efficiency, construction quality control, field curing, minimum tolerable strengths, and field studies of freeze-thaw durability performance).

Weed, R. M., Composite Pay Equations: A General Approach, New Jersey Department of Transportation, March 1994, 23 pp.

Highway construction specifications involving the acceptance testing of several different quality characteristics are sometimes confusing and difficult to administer.   A procedure is developed by which multiple quality measures may be combined in a rational manner in a single, composite pay equation.  This approach is scientifically sound and may be applied to virtually any construction specification for which a relationship between quality and performance is known or can be approximated.  An example based on portland cement concrete pavement is presented to illustrate the practicality of this method.

Weed, R.M., "Equitable Graduated Pay Schedules: An Economic Approach," Transportation Research Record 691, Transportation Research Board, 1978, pp. 27-29.

An approach for establishing graduated pay schedules that are realistic, equitable, and legally defensible is presented.  The method consists of determining the present worth of the extra expense anticipated as a result of work of deficient quality.  An appropriate pay schedule is developed on the premise that it would be justifiable to withhold this amount from the contract price.  The method is applicable for construction items for which data are available that relate quality to performance.   An example is given in which concrete pavement is evaluated in terms of compressive strength.

Whiting, D.A., and S.D. Tayabji, Relationship of Consolidation to Performance of Concrete Pavements, Publication No. FHWA/RD-87/095, Federal Highway Administration, February 1988, 144 pp.

A study was made of the influence of consolidation on properties of portland cement concrete.  Consolidation was found to have a strong influence on compressive strength, bond of concrete to reinforcing steel, and permeability of concrete.  There is a lesser effect of consolidation on resistance to freezing and thawing.  There is a loss of about 30 percent in compressive strength for every 5-percent decrease in consolidation.  A variety of nuclear density gauges were evaluated for use in monitoring consolidation of concrete.  Use of these gauges has remained fairly constant, at relatively low levels, since 1977.  A combination of techniques, such as a consolidation monitoring device (CMD) and commercial direct-transmission gauges, shows promise as a means of monitoring consolidation during the paving process.  A model-acceptance sampling plan for concrete consolidation is proposed.  The plan is of the inspection-by-variables type and requires a sample size of eight per lot.  The plan provides for buyer and seller risks of 5 percent.  Field testing in Idaho and Iowa indicated that monitoring concrete pavement consolidation is practical and economically feasible.

Willenbrock, J.H., and P.A. Kopac, "Development of Price-Adjustment Systems for Statistically Based Highway Construction Specifications," Transportation Research Record 652, Transportation Research Board, 1977, pp. 52-58.

This paper presents a methodology that can be used to develop price adjustment systems for use in statistically based highway construction specifications.  Three approaches are proposed for the development of a price adjustment system: the serviceability approach, the cost-of-production approach, and the operating characteristic curve approach.  The three approaches are discussed and compared, and their most appropriate applications are recommended.  A fourth approach, the cost-of-quality control approach, is also discussed, but it is not fully developed because of the limited cost data available.

Willenbrock, J.H., and P.A. Kopac, A Methodology for the Development of Price Adjustment Systems for Statistically Based Restricted Performance Specifications, Publication No. FHWA-PA-74-27(1), Pennsylvania Department of Transportation, October 1976, 169 pp.

This report presents a methodology that can be used to develop price adjustment systems suited for statistically based, restricted performance specifications.  An example of the use of this methodology for a specific situation, that of bituminous concrete paving for the Pennsylvania DOT, is also presented.

Three approaches are proposed for the development of a price adjustment system: the performance-of-serviceability approach, the cost-of-production approach, and the trial-and-error operating characteristic (OC) curve approach.  A cost-of-quality control approach is also examined, but cannot be fully developed at this time because of the limited cost data available.

Wood, S.L., Evaluation of the Long-Term Properties of Concrete, Research and Development Bulletin RD102T, Portland Cement Association, 1992, 34 pp.

Variations in concrete compressive strength, flexural strength, and modulus of elasticity with time are discussed.  Concrete specimens made from five types of portland cement, portland blast-furnace slag cement, portland-pozzolan cement, and air-entraining cement were tested at ages between 1 day and 34 years.  Relationships between the compressive strength at various ages and the 28-day compressive strength are developed for specimens stored in moist and dry environments.  Flexural strength and modulus of elasticity are related to the compressive strength.

Woodstrom, J.H., Measurements, Specifications, and Achievements of Smoothness for Pavement Construction, Synthesis of Highway Practice 167, National Cooperative Highway Research Program, 1990, 34 pp.

Smoothness-measuring equipment currently used in new pavement construction includes straightedges (static and rolling), profilographs, response-type road-roughness-measuring systems, and inertial profilometers.  The fundamentals of operation, cost, and appropriateness to address a specific need vary considerably.  Certain devices are far better suited than others to the purpose of controlling the smoothness of newly constructed pavements.  Therefore, it is important for those concerned with obtaining smoothness in construction to be aware of the equipment best suited for that purpose and the relationship of that equipment to the entire spectrum of smoothness-measuring devices.

Numerous research efforts, as well as symposia and workshops, have been directed toward providing information on the issue of smoothness-measuring equipment.  Although there are vast differences in equipment types and their ultimate application, the relationships of several smoothness indexes have been compared and are reasonably well-defined.

A survey of practices in use in the United States and Canada revealed great diversity in the use of smoothness specifications and equipment.  However, emphasis on smoothness by specifying agencies, together with strong support form the construction industry, has led to the attainment of increasingly smoother pavements.

Wu, S., and H.M. Hearne, Jr., "Performance of Concrete Pavement With Econocrete Base," Proceedings, 4th International Conference on Concrete Pavement Design and Rehabilitation, Purdue University, 1989, pp. 683-695.

A three-lane, 16-mi (25.7-km) section of I-85 in Randolph and Davidson Counties, North Carolina, was opened to traffic in 1984.  The spring following the opening of this section of highway, reddish-brown stains were visible on the concrete shoulders.   Water was determined to be flowing under the slabs and blowing out through weak points along the joints.  The data collected in an attempt to understand this phenomenon included horizontal and vertical movements of the slabs, static and dynamic pavement deflections, temperature gradients of the pavement system, location of dowels in the slabs, concrete and soil material properties, and field observations to identify water movement.  Possible causes of the problems were identified, and methods to minimize damage to the pavement were recommended.

Zia, P., and M.R. Hansen, "Durability of High-Performance Concrete," Pacific Rim TransTech Conference Proceedings. Volume II, American Society of Civil Engineers, 1993, pp. 398-404.

This is a summary of a study of the freeze-thaw (F/T) durability and resistance to chloride penetration of high-performance concrete (HPC) developed for highway applications.  The tests covered here include the freeze-thaw test, rapid chloride permeability test (RCPT), and impedance test. It was found that the F/T resistance of the HPC exceeded the enhanced F/T durability requirement by a considerable margin.  This can be achieved if the concrete has a minimum of 5 percent well-entrained air and the coarse aggregate used in the concrete is F/T-resistant.  Despite its high F/T resistance, HPC may indicate quite high coulomb values in the RCPT because of the additional ions introduced into the concrete by the various admixtures.

Zollinger, D.G., T. Tang, and D. Xin, "Sawcut Depth Requirements for Concrete Pavement Based on Fracture Mechanics Analysis," Prepared for the 72nd Annual Meeting of the Transportation Research Board, January 1993, 52 pp.

The efficient control of slab cracking is important to concrete pavement performance.   From the viewpoint of engineering analysis and the design of pavements, it is desirable to control pavement cracking to joint locations to decrease the possibility of uncontrolled cracking.  The purpose of this paper is to suggest an approach to estimate appropriate sawcut depths and placement timing using fracture mechanics for jointed concrete systems.  Early age sawcutting, as one form of crack induction, has been applied to concrete pavement surfaces at specific contraction joint locations.  This paper presents a mechanics-based approach to the determination of sawcut depth and spacing requirements using fracture mechanics analysis.  The stress field in a concrete slab induced by thermal and shrinkage gradients is based on curling and warping analysis, which also leads to sawcut spacing criteria.  Fracture parameters Klf and Cf defined by the size effect law are obtained from laboratory-notched beam fracture tests for specific coarse aggregate types.  Modified linear elastic fracture mechanics is applied to determine a sufficient notch or sawcut depth to ensure controlled cracking.  The theoretical sawcut depth, as determined by fracture analysis, is significantly less than the conventional d/3 or d/4, where d is the slab thickness.  Recent pavement surveys have verified this conclusion.