The long-term general objective of this research is to provide information on the selection and use of antistripping additives which are materials used to improve the asphalt-aggregate adhesion in asphalt concrete. A laboratory study has been completed, and the immediate specific objectives of the current research are, by means of a field study, to (1) measure the long-term effectiveness of antistripping additives in preventing moisture damage, and (2) determine the ability of laboratory tests to measure antistripping additive performance. Full-scale test projects, each including a control section with no additive and a test section containing an antistripping additive, have been built in eight states, and extensive laboratory testing of the materials and mixtures from these projects has been completed. The field evaluation phase of the research includes testing of cores and condition surveys. Agreement between cores and condition surveys is very good. After 6 to 8 years, the performance of 8 of the 9 additives was satisfactory. The exception was an additive that did not perform as well as the control section. The original laboratory tests correctly predicted pavement performance found by the field evaluation on 6 of the 8 projects. On one project an additive section performed worse than expected. On another project the experimental sections were never wet. Altogether, the expected performance was found on 16 of the 19 experimental sections. The conclusion is that the original laboratory test is suitable for use in moisture damage testing and additive evaluation. (A)
Abstract