A Comprehensive Pavement Evaluation System: Application to CRCP (FHWA/IN/JHRP-76/02)
Since 1972, a continuing study of the performance of CRC pavements has been in progress at the Joint Highway Research Project, Purdue University. The objective of the research program is to evaluate and recommend design and construction techniques that would help to improve the performance of CRCP.
The evaluation study consisted of the following sequential steps :
- Reconnaissance survey
- Pavement condition survey
- Detailed field evaluation survey
This approach permitted considerable flexibility in the conduct of the research. Each sequential step in the research was designed on the basis of the results of the previous step. As a result, considerable economy in the research effort was obtained.
The CRC pavement condition survey was conducted on a statewide basis wherein every CRCP construction contract in Indiana was included in the survey. A total of 89 survey sections, each 5000 ft in length, were used. These were obtained by random sampling, stratified over the following factors: construction contract, method of paving, method of steel placement, method of steel fabrication (type of reinforcement), subbase type and subgrade parent material.
The results of the CRC pavement condition surveys indicated that subbase type, methods of steel placement and steel fabrication, concrete slump, and age of the pavement since opened to traffic were significant contributors to pavement performance.
Based on these results, a field investigation of CRC pavements was conducted. The purpose of this phase of the research was to evaluate the parameters that were found to contribute significantly to CRCP performance in the condition survey. This was accomplished by conducting a field testing program on in-service CRC pavement sections.
For this part of the study, the length of test sections was taken as 1000 ft. Normally these test sections were required to lie within the condition survey sections so that a wide inference space, in terms of the independent explanatory variables, could be maintained.
All the test sections were located on Interstate Highways in order to obtain a homogeneous set of test sections in terms of thickness, 9-inches (22.9 cm) and traffic intensity. Where possible, a good location was compared with a failed location within each test section.
This paper describes:
- Concepts underlying the comprehensive evaluation system.
- Method of setting up the condition survey.
- Method of making the evaluation survey.
- Use of the results of the surveys for establishing a maintenance research project for CRCP.
Some of the significant findings of the study are included. The results of the study show that failures in CRCP are a function of a number of interacting variables. Generally higher pavement deflection, wider crack widths and nonuniform crack patterns were associated with failed pavement condition. The support conditions under CRCP are of particular significance relative to performance. Granular subbases with high stability and good internal drainage have shown good performance.
Authors: Eldon J. Yoder, Asif Faiz, and D. G. Shurig