Integrated experimental-numerical approach to model progressive moisture damage behavior of bituminous paving mixtures

This paper presents an integrated experimental-numerical approach to model the progressive moisture damage characteristics of bituminous paving mixtures. To this end, a Fickian model is utilized to determine the diffusion coefficient, which is a key property of simulating moisture transport causing moisture damage, and the semicircular bend (SCB) fracture tests are carried out to obtain the elastic stiffness and fracture properties at different levels of moisture conditioning. A sequentially coupled moisture diffusion and mechanical loading is implemented using a finite element method to model the progressive damage behavior due to the moisture transport followed by the mechanical loading. To simulate the fracture process as a gradual separation, a cohesive zone model is incorporated into the model. The integrated approach presented herein results in a degradation function that characterizes the progressive damage due to moisture uptake with two model parameters representing the remaining properties of materials and their degradation trend. These two model parameters can be used to estimate moisture damage mechanisms and damage resistance potential, both of which are material specific.