A study of moisture-induced cracking during a short-term rain event in a pre-cracked asphalt concrete pavement with an expansive base layer

摘要

A model is developed herein for predicting moisture-induced crack growth during a short-term rain event, considered herein to be of duration not greater than 2 hr, in a pre-cracked asphalt concrete pavement built on an expansive base layer. The model is in two parts, the first being the prediction of moisture transport into the pavement, and this part is accompanied by an experimental component focused on measuring the diffusivity of moisture in asphalt concrete. The second part of the model deals with the prediction of the effect of moisture transport on the subsequent mechanical behaviour of the pavement, with emphasis placed on the initiation and propagation of an additional surface crack due to expansion of the base layer. Both components of the model are developed computationally via the use of an in-house one-way coupled finite element code, and a description of this algorithm is briefly reviewed herein. The model developed suggests that the pre-existing crack must extend completely through the asphalt concrete layer into the highly permeable and expansive base layer for there to be significant moisture transport during a short-term rain event. In the case wherein the initial crack extends into the base layer, the stress concentration induced due to dilatation of the base layer upon moisture absorption is predicted to cause additional cracking rapidly.