Mechanistic evaluation of cracking in in-service asphalt pavements

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Cracking in asphalt pavements is a complex problem that is affected by pavement structural design, material properties, and environmental conditions. It is now well accepted that load-related top-down fatigue cracking (i.e., cracking that initiates at the surface of the pavement and propagates downward) commonly occurs in asphalt pavements. Conventional fracture mechanics-based finite element analysis must assume the location of macrocrack initiation a priori and, therefore, is not appropriate for general-purpose cracking simulation. This paper presents the use of the layered viscoelastic pavement analysis for critical distresses (LVECD) program to evaluate 18 pavements in local condition regions of 9 in-service pavement sites in North Carolina. In order to obtain the material properties of the individual layers from the field-extracted cores, dynamic modulus tests and simplified viscoelastic continuum damage tests are performed using small geometry specimens obtained from 150 mm diameter cores. This study verifies the capability of the LVECD model to capture crack initiation locations, propagation propensity, and cracking severity by comparing the simulation results with the observations of field cores and the field condition survey of in-service pavements in North Carolina. Overall, the agreement rate between the field core observations and field condition survey and the predicted LVECD simulation results is about 78 % in terms of cracking direction and severity.