Research on the crack resistance of semi-flexible pavement mixture based on meso-heterogeneous model

Abstract

Semi-Flexible Pavement (SFP) material, prepared by pouring cement-based grouting material into the voids of a porous asphalt mixture, has good load bearing capacity and excellent resistance to rutting. It is gaining increased applications in areas where permanent deformation of asphalt mixtures is a concern. When applied as the pavement surface course, the major distress observed in SFP is cracking. Currently, there is a lack of comprehensive understanding of the cracking mechanism of SFP. To improve such understanding, this study investigated the effects of fracture parameters of asphalt mortar and asphalt-aggregate interface on the crack resistance of SFP materials through laboratory experiments and numerical simulation using the finite element method. Firstly, a three-point bending test was performed on a beam SFP specimen. A multi-scale mesoscopic heterogeneity model was then established based on the mesoscopic structure of the specimen and calibrated and validated using the load-displacement curves and the cracking process features. With the validated model, the effects of different fracture parameters on the beam cracking process were investigated. It was found that the load-bearing capacity of SFP increased with the increase of the tensile strength of asphalt mortar and asphalt-aggregate interface in a certain range, while the crack propagation rate after crack initiation also increased. An increase in the fracture energy of asphalt mortar and asphalt-aggregate interface delayed the crack propagation rate, but with an attenuative effect with the increase of fracture energy. Based on the actual test conditions, the desirable range of key cracking parameters of SFP materials were recommended.