Using Surface Deflection for Detection of Interface Damage Between Pavement Layers

ABSTRACT In order to detect interface flaws between bituminous and hydraulic layers of composite pavements, three-dimensional finite element simulations of the deflection under a standard axle load were carried out. The pavement layers are considered as linear elastic and the interface behaviour follows three different hypotheses: perfectly bonded, perfectly smooth and frictional. The load is moved above the flaw and the deflection curve of the pavement surface is registered. The first derivative of this last and the curvature radius are calculated numerically. Different measurement modes under moving loads are considered using either pavement fixed or vehicle fixed sensors during the measurement recording. The presence of an interface flaw does not affect significantly the deflection curve. Inversely, the first derivative of the deflection curve and the curvature radius beneath the wheel load provide suitable indicator of the flaw presence and extension.