Modeling Capillary Water Absorption in Concrete with Discrete Crack Network

Understanding capillary water absorption in concrete is of major significance for the durability assessment of concrete structures, particularly when cracks are present. The paper develops a three-dimensional (3D) finite-element (FE) model to simulate water absorption in concrete samples with discrete crack networks. In this model, the uncracked domain is discretized into solid elements whereas discrete cracks are modeled by zero-thickness crack elements, with the unsaturated flow theory applied to describe the water penetration process. The proposed model is validated by comparing with experimental data from the literature. Concrete samples containing randomly generated 3D crack networks are employed for investigating water uptake, and the effects of crack configurations (i.e., crack density, length, and width) on the sorptivity are evaluated numerically. The proposed model is shown to be capable of simulating the capillary flow within unsaturated cracked concrete, indicating that the discrete cracks play a significant role in accelerating the absorption rate of water.