The Effect of Crushing of Unbound Granular Materials Forming Part of Flexible Pavement Systems

Due to loading, granular materials forming the base of asphalt pavements experience crushing. After crushing, the fines produced in the granular materials move into their voids and causes an increase on the bearing capacity of the base. However, when the volume of the voids is decreased due to this fines migration, the hydraulic conductivity of the crushed material decreases. This change in the hydraulic conductivity of the material with time, may lead to failure of the pavement. Compression induced crushing and hydraulic conductivity tests were conducted on small gravels. In this study, the level of fragmentation of two kind of gravels (smooth and angular) was analyzed using fractal theory. The fractal dimension concept was used to evaluate the level of fragmentation of the gravels and it was correlated with their hydraulic conductivity values. The level of crushing in the gravels was also visualized using DEM.