Performance-based design of hard asphalt mixtures based on different compaction effort variable

Abstract

Due to potential thermal cracking risks, marginal hard asphalt has not been widely used in China. A design method for hard asphalt under lower compaction levels was adopted in the present study with the aim of compensating for low-temperature cracking problems by increasing the asphalt content; simultaneously, the rutting resistance can still be maintained due to the high stiffness of hard asphalt itself. Four groups of asphalt, i.e. a control group (70# asphalt under Ndes = 75); two experimental groups (30# and 50# asphalt under Ndes = 50); and an analysis group (70# asphalt under Ndes = 50), were designed to evaluate the performance. Based on the experimental results, the conventional and this design method using 50# hard asphalt showed almost the same high- and low-temperature resistance. It is noteworthy that this method exhibited better fatigue resistance and increased fatigue life by approximately 1.6 times. In addition, this method also showed a larger dynamic modulus, especially under the traffic conditions of low frequency or high temperature. These results may indicate that a cheap marginal hard asphalt mixture under less compaction energy could achieve an even better performance than the conventional asphalt.