Prediction of thermal crack spacing

When the thermally induced stress in a shrinking pavement layer reaches the tensile strength of asphalt, regularly spaced thermal cracks form across the width of the pavement. A one-dimensional analytical solution for the stress distribution in a thermally shrinking elastic pavement layer placed on an elastoplastic, cohesive-frictional base is developed and validated by comparison with a 2D numerical solution. From the analytical model, a prediction of a length parameter that provides bounds on the thermal crack spacing is obtained. Predicted bounds on crack spacing are validated by comparison with field observations. It is demonstrated that the proposed formulation can also be applied to estimate the average crack density observed in thin ceramic films subjected to the application of an axial strain; in the latter system, the crack spacing is six decades smaller than that observed in pavement systems. (C) 2002 Elsevier Science Ltd. All rights reserved.