Validation of Contractor HMA Testing Data in the Materials Acceptance Process

摘要

This study conducted an analysis of the SCDOT HMA specification. A Research Steering Committee comprised of SCDOT, FHWA, and Industry representatives provided oversight of the process. The research process included a literature review, a brief survey to which 42 highway agencies replied, in-person interviews with a few selected agencies, and extensive statistical analyses of test data supplied by SCDOT. Analyses were conducted to determine appropriate standard deviation values to represent the variability of each of the acceptance characteristics used by SCDOT. A total of 1,260 density test results were provided from 22 different projects. A total of 1,775 asphalt content (AC) tests and 1,343 air voids (AV) and VMA tests were provided from 30 different projects. In addition, SCDOT verification test results were obtained from 10 projects and were analyzed and compared with their corresponding contractor acceptance tests. The previous and current SCDOT verification procedures were evaluated and issues concerning each were presented and discussed. Ranges for the appropriate values to use for the within-lot standard deviations for Density, AC, AV, and VMA were also developed. The analysis of verification tests results resulted in new verification testing procedures that were recommended for consideration by SCDOT.