Research on the rubber-asphalt mixtures based on GTM design method

In order to investigate gradations and the pavement performance of rubber-asphalt mixtures, the GTM (Gyratory Testing Machine), which is a gyratory compaction molding method for rubber-asphalt mixture design, was used for the first time in China. Based on this method, continuous-gradation and three types of gap-gradation mixtures with different through-rates of 4.75mm were examined systematically. Without considering the volume parameters, the optimum asphalt content was identified according to the physical and mechanical parameters, including the GSI (gyratory stability index) and GSF (gyratory safety factor). The rubber-asphalt mixtures with different gradations and molding modes were expanded linearly considering the parameters mentioned above. The results indicate that dense-graded rubber-asphalt mixtures can be used based on the GTM design method. Through a comprehensive evaluation on the pavement performance, it is concluded that the GTM design method is more appropriate for dense-grade rubber-asphalt mixtures and that pavement performance with the GTM design method is superior to that of the gap-grade mixtures.