Stripping in asphalt concrete, has long been recognized as a cause of premature pavement damage. Yet, after many years of research and application, there are few generally accepted conclusions about the severity of the problem, the nature and causes of the process, ormethods for evaluating stripping. The evolution of test procedures for assessing stripping potential appears to be progressing toward procedures that measure strength loss of moisture-conditioned mixtures compacted to to 8 percent voids. Indirect tensile tests were performed on asphalt concrete mixes composed of materials common in Alabama. The purpose of these tests was to study the stripping process and to evaluate the test procedure for assessing stripping potential. Results indicate that published moisture-conditioning procedures produce variable strength loss but that either of the two procedures evaluated is acceptable. Results also indicate that asphalt cement content, as well as type of mix, has a significant influence on test results and that generalities concerning stripping potential of aggregate sources, types, and blends are not valid. Finally, test results did not distinctly delineate reported stripping and nonstripping aggregate combinations. Reasons may be that the reported performance of an aggregate combination is not valid for all mix types, or that the test is not a positive indicator of stripping potential. The former is more likely, but incorrect predictions for specific mixes area definite possibility. Implications are that specific mix designs must be tested and results conservatively interpreted until field performance studies permit further refinements.(A).
Abstract