Prediction of the Cracking Effect on Mass Penetration into Unsaturated Concrete

Abstract

Cracking of concrete, which may induced by environmental action or mechanical loading, has been identified as one of the major factors controlling the long-term performance of concrete structures because it can provide preferential pathways for the ingress agents (e.g. water or chloride ions). In the current work, the transport coefficients of water and chloride through a single crack are developed by treating it as a parallel-plate configuration. The physical migration models coupled with capillary absorption and convection-diffusion are utilized to predict water penetration and chloride ingress into cracked concrete. By means of the mesoscale computational method that concrete is modeled as a composite of impermeable coarse aggregate embedded in the porous matrix separated by vulnerable interfacial transition zone, the lattice network model is presented to investigate water and chloride transport properties in cracked concrete. The influence of cracking and the actual saturation level on the transport process of water and chlorides are investigated numerically. The numerical results indicated that the computational method is able to well represent the mass movement within cracked concrete. The effect of saturation level and cracks on water and chloride transport process is of great importance.