Fracture analysis of aggregate interlock jointed slabs-on-grade

This paper discusses finite element analysis of crack propagation in pavement slabs-on-grade with aggregate interlock joints, using the finite element package ABAQUS®6.9-2. The fracture process is idealized using nonlinear fracture mechanics approach implemented through cohesive elements. Load transfer at the joint is achieved by aggregate interlock mechanism simulated in accordance with Walraven's nonlinear constitutive relations. The proposed discretization is first verified by comparing the pre-crack responses with experimental and numerical results published by independent researchers. Then the discretization is extended to post-crack analysis of slab responses. Parametric studies are conducted concerning the effects of joint opening and aggregate size on post-crack pavement responses. It is observed that load transfer efficiency with respect to load, vertical and crack mouth opening displacements decreases almost linearly with increasing joint opening. Aggregate size is found to have a negligible effect when the initial joint opening is small. On the other hand, as initial joint opening increases, larger aggregate particles result in stiffer joint behavior. A daytime temperature profile is observed to reduce both the peak load supported by the slab system and the load transfer efficiency of the joint, while a nighttime temperature distribution results in modest increases in these metrics. It is concluded that the proposed approach lays a computational basis for further exploration of fracture analysis in jointed slab-on-grade systems. The step-by-step methodology implemented in this study may contribute to the ongoing development of rational failure criteria that can replace the statistical/empirical algorithms currently used in pavement design procedures.