Mechanism Analysis of the Use of LSPM for Reflection Crack Prevention of Semi-Rigid Base Asphalt Mixture

Abstract

The damage mechanism of reflective cracking, particularly on semi-rigid asphalt pavement with large stone porous asphalt mixture (LSPM) is investigated in this study. An asphalt pavement model with multilayered base (i.e., LSPM and semirigid layer) using discrete element method is developed. This study analyzes the influence of the inner structure of asphalt mixture on the stress field around the crack tip, which is under the vehicle load after the cracking of a semi-rigid layer. The focus is on the mechanism of cracking and the influence of the inner structure of the mixture, such as gradation, the geometric feature of coarse aggregate, and space. The crack expansion rate is also analyzed. Results show that, under vehicle load, the crack in the semi-rigid layer causes stress concentration, which decreases around the bottom of the LSPM. The load on the top of the crack tip produces stress level concentration, the unbalanced load produces shear stress concentration, and the stress decreases progressively from the crack tip to the surrounding area. In the LSPM, a large grain size of the coarse aggregate is better than a small grain size. Its overall stress level is low and the crack development rate is slow on the stress field of the crack tip. The LSPM can reduce stress concentration and prevent the development of reflective cracking effect.