Performance-Related Specifications for Pcc Pavements. Volume II: Appendix B-Field Demonstrations

Introduction

A prototype performance-related specification (PRS) for jointed plain concrete pavement (JPCP) was developed in a previous Federal Highway Administration (FHWA) study.^(1-4) This prototype has been revised under the current project to make it more practical and implementable. As a means of assessing its practicality, three different methods were used to demonstrate and test both developed specification levels (Level 1 and Level 2).

The first method of demonstrating the prototype PRS involved the conduct of field trials at four actual new construction projects (one conducted by the research team, and the other three in conjunction with FHWA Office of Technology Applications [OTA] personnel). The PRS simulation software (PaveSpec) was used to develop the Level 1 and Level 2 preconstruction output for each project (reflecting the project-specific design, climatic, and traffic conditions). A PRS-based sampling and testing plan was then applied, and the required samples were collected to demonstrate both Level 1 and Level 2 procedures. Finally, the PaveSpec simulation software was used to determine shadow pay factors and adjustments for each project (i.e., the contractor’s pay was not affected by the PRS-based pay factors and adjustments computed as part of the demonstration).

The second demonstration method involved developing Level 1 specifications for three typical designs used by a State Highway Agency (SHA). It was decided to develop these specifications for typical designs in Iowa since it was the site of the first shadow field trial. Preconstruction output (pay factor charts and corresponding equations) were developed for each of the chosen designs. Finally, the trends within and between each project’s preconstruction output was analyzed.

The third demonstration method consisted of comparing historical pay adjustments (actually paid by the SHA) to PRS-based price adjustments predicted for the same pavement lots. This study was conducted using historical (archived) acceptance quality characteristic (AQC) and pay adjustment data. Archived data were retrieved for a total of 41 lots from 7 projects in 3 States. Next, Level 1 preconstruction output (pay factor charts and corresponding equations) were developed for each project being investigated. The retrieved AQC data were then used in conjunction with the Level 1 preconstruction output to determine PRS-based Level 1 lot pay factors. Historical pay adjustment data representing the same defined lots were then obtained and compared to the computed PRS-based pay adjustments.

This volume shows details of the three methods used to demonstrate the revised prototype PRS. Its specific purpose is to illustrate the investigation into the specification’s practicality and implementability. Chapter 2 contains a summary of the original PRS shadow field trial conducted by the research team in Ottumwa, Iowa. Chapter 3 discusses the details of the three additional shadow field trials conducted in conjunction with OTA personnel. Chapter 4 discusses the development of the Level 1 specifications for three typical pavement designs for a chosen SHA (Iowa). Chapter 5 includes details of the study using historical SHA data to compare actual historical pay adjustments to predicted PRS-based pay adjustments for the same pavement lots. Finally, chapter 6 summarizes the results of these different demonstrations used to assess the revised prototype PRS’s practicality and implementability.