Cost Benefit Analysis of Anti-Strip Additives in Hot Mix Asphalt with Various Aggregates.

摘要

This report documents research on moisture sensitivity testing of hot-mix asphalt (HMA) mixes in Pennsylvania and the associated use of antistrip. The primary objective of the research was to evaluate and compare benefit/cost ratios of mandatory use of antistrip, and of antistrip usage conditional on the results of moisture resistance testing, based upon life cycle cost analyses. A secondary objective was to evaluate a unique version of the modified Lottman procedure used in Pennsylvania between 2003 and October 2014, which involved a relatively low level of saturation in specimen conditioning. This procedure (low-saturation method) typically results in saturation between about 30 % and 67 %, as compared to the 70 to 80 % required in the test version used by Pennsylvania prior to 2003 and after October 2014 (high-saturation method). It was found that the low-saturation method passed all HMA mixes, even those with a documented history of high susceptibility to moisture damage. This procedure therefore had a benefit/cost ratio of zero. For the high-saturation method, it was found that both antistrip usage dependent on the results of testing and mandatory usage for all mixes had benefit/cost ratios that were greater than one and in general much greater than one. The benefit/cost ratios for mandatory antistrip usage were greater than those for conditional usage, because of the high cost associated with the failure of moisture resistance testing to identify all moisture susceptible mixes.