An Experimental Investigation into the Effect of Asphalt Binder Modified with SBR Polymer on the Moisture Susceptibility of Asphalt Mixtures

Abstract

There are several experimental methods for improving the moisture strength of asphalt mixtures. Utilization of anti-stripping materials is the most prevalent method. In the present paper, the influence of polymer materials on asphalt binder was investigated using repetitive loading test in wet and dry conditions along with thermodynamic parameters based on the Surface Free Energy components of asphalt binder and aggregates. The results obtained from the present study indicated that using Styrene Butadiene Rubber polymer has improved the asphalt mixtures strength against the moisture damage, especially in the specimens made of granite aggregates. Also, Styrene Butadiene Rubber polymer increased the cohesion free energy and reduced the energy released by the system during the stripping event, which represented a decrease in the tendency for stripping. The stripping percentage index, which is obtained by a combination of the results of the repetitive loading test in wet and dry conditions along with the results of thermodynamic parameters, represented that the specimens made of controlled asphalt binder in the loading cycles under wet conditions had a higher stripping rate. It was also concluded that the modulus loss rate in the control asphalt mixtures was faster than the modified specimens.