Investigating the skeleton behaviors of open-graded friction course using discrete element method

Abstract

Behaviors of aggregate skeletons are of critical importance on the performance of Open-graded Friction Course (OGFC). This study quantitatively investigated the effect of gradation on the skeleton behaviors using discrete element method (DEM). Four different gradations of OGFCs and one dense-graded aggregate gradation were selected. Two types of tests were carried out, named as the cyclic compressive test and the penetration test. The ‘strong’ and ‘weak’ contact networks were generated, and the fabric anisotropy was analyzed. Moreover, parameters including the peak penetration strength and coordination number derived from the penetration tests were employed to evaluate the skeleton performance. Results show that the gradation significantly affects the penetration strength. The coarser the gradation, the larger the penetration strength. Three stages in the penetration process can be divided, which associated with the original skeleton damage, particles' rearrangement and densification. The proportion of strong contact and the penetration strength show a linear correlation.