Empirical Study of High Strain Rate Loading and Fragmentation of Hot Mix Asphalt

Abstract

Dynamic fragmentation of hot mix asphalt (HMA) under high strain rate loading can be expected under various situations, such as milling, earthquakes, or explosions. This paper reports on an empirical study that was conducted to investigate the dynamic fragmentation of HMA, specifically with respect to energy of impact during loading. Samples of a surface course HMA, compacted to similar densities, were subjected to a series of impact loadings with different energies. The depth of penetration into the sample, strains during loading, and the resulting fragment sizes were evaluated. Impacts with higher energy levels produced more fragmentation and larger fragments. Both penetration and strains showed significant effects of impact energies. The size of the fragments showed good correlation with impact energy. These results can be utilized for controlling reclaimed asphalt pavement (RAP) gradation from milling and, hence, among other things, for constructing longer-lasting pavements.