Performance Analysis and Research of Warm Asphalt Rubber

Warm mixture asphalt has been used worldwide aiming to save energy and reduce emissions without decreasing in-service performance. In this paper, the influences of conventional physical properties of warm asphalt rubber (WAR) are studied by orthogonal test, analysis of variance (ANOVA), and range analysis for three factors (crumb rubber modifier [CRM] particle size, CRM content, and warm asphalt additive [WAA]), and levels. The results show CRM particle size is the main factor on the effect of nearly all the investigated indexes, especially temperature susceptibility of WAR binders, and the performance of WAR containing 60 meshes is very close with that of 80 meshes. The impact of content of CRM comes second. Besides penetration index, the other performances improve as the content of CRM increases. The high content of WAA is favorable to high temperature and temperature sensitivity as well as bad to low-temperature performance slightly.