Evaluation on performance characteristics of superpave asphalt mix design under tropical climatic conditions

Abstract

During the last decade, hot-mix asphalt (HMA) mixture design has undergone major changes with respect to mix design method and mix characterization. Currently in tropical climatic countries,the Marshall mix design method is still used to construct HMA pavements. Therefore, this study was conducted to investigate the performance characteristics of Superpave and Marshall method design HMA mixtures in tropical climatic conditions. Laboratory tests were conducted to evaluate the rutting (permanent deformation) and resilient modulus of different Superpave and Marshall mixes. In addition, dynamic modulus tests by means of the Simple Performance Test (SPT) were also conducted. The relationships between the SPT dynamic modulus test and other performance test results were also examined. It was found that the Superpave-mix design showed far superior performance compared to the Marshall-mix design based on all types of testing in this study. Since the dynamic modulus test provides full characterization of the mix over a broad range of temperatures and loading frequencies, this test is highly recommended for Superpave mixture characterization under tropical climatic conditions.