Experimental and discrete element numerical analysis on mode-I fracture characteristics of cement-stabilised macadam base

This is the authors' abstract. We don't add key points for this paper.

Cracking in cement-stabilised macadam (CSM) bases is a typical failure mode in semi-rigid pavements, yet the quantitative correlation between macroscopic failure and mesoscopic damage evolution remains unclear. In this study, three-point bending tests, acoustic emission (AE) monitoring, and a three-dimensional discrete element method (DEM) model were utilized to investigate the fracture characteristics of CSM, establishing a quantitative link between cumulative AE energy and the physical damage variable DAE. Results indicated that CSM specimens exhibited insignificant damage below 91% of the peak load, but underwent rapid damage propagation and brittle fracture beyond this point, accompanied by significantly increased AE activity. Correlation analysis of the RA–AF values confirmed that tensile cracks were the predominant damage mechanism. Micro-cracks were generated at the peak-force point, accounting for only 10% - 20% of the total cracks. Across different strain rates, the P-CMOD curves remained consistent; however, higher strain rates increased the peak load while decreasing the number of cracks. This phenomenon is attributed to the rate-dependent transition of failure modes: at high strain rates, inertial effects forced cracks to penetrate directly through aggregates, reducing crack branching. Furthermore, as the strain rate increased from 1×10-5s-1 to 1×10-1s-1, shear failure contacts diminished, while the proportion of tensile cracks decreased by 34%.