Bump formation on a semi-rigid pavement: Interpretation and modeling using the thick level set (TLS) approach for damage growth

Abstract

This paper is focused on the understanding of the origin of a bump a few centimeters high which suddenly popped up at the surface of a semi-rigid pavement composed of a bituminous layer placed over a cement concrete layer of 20 cm in thickness. Field investigations have shown that this bump developed right above a cement joint which had already undergone maintenance operations consisting in particular in the digging of trenches and resulting in a decrease of the cement layer thickness at the joint location. It was also noticed that the bump appeared during a warm day and in a wet area, which are both source of dilation. In this context, we suspect the mechanism at the origin of the bump to be triggered by compressive forces at the joint location whose effect is the bending of the cement layer and eventually failure by means of crack propagation in mode I (opening mode) due to excessive tensile stress. This paper aims at providing an accurate description of this field case which is modeled using the Thick Level Set (TLS) approach that proposes a straightforward transition from damage growth to fracture. The numerical implementation of the TLS approach is handled within the X-FEM framework. The results from the computations tend to confirm the suspected mechanism.