Field validation and parametric study of a thermal crack spacing model

Thermal cracking of asphalt pavements is a common mode of distress leading to premature deterioration and failure of the pavement system. As such, much research has been devoted to the thermal cracking phenomenon. Recently, a mechanistic model that predicts the spacing between cracks has been developed. This model, the accounts for both the asphalt concrete surface layer and supporting granular medium, is briefly described. Further, a field validation study using live pavement test sections from the MnROAD project is presented. In addition, to better understand the model behavior, a parametric study is undertaken. It was found that model predictions compared favorably with field section observations. Also the crack spacing derived by the model was most influenced by the stiffness of the asphalt concrete and supporting layer, the thermal coefficient of contraction of the asphalt concrete, and the frictional properties of the unbound supporting layer. In the future, the model could be used to predict crack spacing as a function of environmental conditions and material types and help plan mitigation strategies.