Modeling of water permeability in early aged concrete with cracks based on micro pore structure

摘要

The pores and pore connectivity in concrete cause rapid water permeation. This is an important characteristic of porous material. Cracks in early aged concrete can be easily caused by restraint stress due to the process of hydration heat or drying shrinkage. Cracked concrete is vulnerable to water permeation. This can lead to rapid corrosion of the steel inside. In this paper, numerical modeling of water permeability in cracked concrete is performed, considering the behavior of early aged concrete such as porosity and saturation. Previously developed models that cover hydration, pore structure, and moisture transport are analyzed. The crack effect on water permeation in a representative elementary volume (REV) is analytically derived through averaging water permeation in sound concrete and crack width. An analysis technique is proposed through the equivalent permeability model in REV. Thirty-three concrete samples with crack width of 0.1-0.4 mm are prepared and water penetration tests (WPT) are performed to verify the proposed technique. The proposed technique is evaluated to reasonably predict both the increasing permeability with crack opening and the decreasing permeability with extended curing period.