EVALUATING MOISTURE SUSCEPTIBILITY OF ASPHALT MIXTURES USING THE TEXAS BOILING TEST

A description of the development and use of the Texas boiling test to evaluate stripping of materials susceptible to moisture damage is presented. Based on a review and comparison of boiling tests currently in use by several agencies and a limited test evaluation program, a tentative test procedure was prepared and used for all subsequent testing. Tests were performed on eight mixtures, of which five had stripped in the field and three had not. Each mixture and its individual aggregate components were tested to determine if the results could be used to differentiate between stripping and nonstripping mixtures. Because antistripping additives are commonly used in strippingprone mixtures, a few additives and aggregate combinations were tested to determine if test results were affected by the presence of these additives. Test results indicate that valuable information is provided by the Texas boiling test. The test is simple and easy to perform; it can be performed either in the laboratory during mixture design or on field-mixed mixtures. Evaluation of known aggregates and various antistripping additives indicates that the Texas boiling test generally can be used to detect moisture-susceptible mixtures.