Prediction of shrinkage cracking and corresponding cracking prevention measure of the semi-rigid base layer

摘要

Shrinkage cracking resulting from the shrinkage stress of the semi-rigid base layer is a dominant factor leading to failures of asphalt pavements with semi-rigid base layers. The calculation model of the shrinkage stress, which is caused by dry and thermal shrinkage, of the semi-rigid base layer was established. Based on the calculation model, the expression of the shrinkage stress of the semi-rigid base layer was deduced and the maximum value of the shrinkage stress was calculated, and the position of the maximum value was presented. Besides, the influencing factors of the maximum value of the shrinkage stress and the cracking rule of shrinkage cracks were analysed. The results indicate that the maximum value of the shrinkage stress can be reduced by decreasing the length of the semi-rigid base layer to control the free shrinkage of the base layer. In this paper, the cracking prevention measure of setting pre-cutting slots in the semi-rigid base layer is presented, and the setting details are introduced.