SUMMARY REPORT ON WATER SENSITIVITY

Abstract

This report reviews and summarizes the current information and the 'state of the practice' in the evaluation of asphalt paving mixtures or water sensitivity. The information is then applied to two major goals of the Strategic Highway Research Program (SHRP): definition water sensitivity of asphalt concrete mixtures with respect to performance, including fatigue, permanent deformation, and low temperature cracking as well as the effect of aging; development laboratory testing procedures that will predict field performance. The report includes an evaluation of laboratory procedures currently being used and an assessment of the extent of use for each method. Several areas of needed research are discussed, and possible methodology is presented. The planned research approach is outlined. It was found that a wide range of procedures are being used by state Departments of Transportation, and there is apparently no procedure that is universally acceptable. A working hypothesis is proposed, stating that the presence of voids in the 'pessimum' range may be a major cause of moisture damage in conventional asphalt concrete mixtures. A scheme for evaluating the hypothesis is outlined.