Study on chloride diffusivity coefficient in cracks within saturated concrete

Cracks within concrete can accelerate the ingress velocity of chloride ions into concrete, causing the accelerated degradation of mechanical performances of reinforced concrete structures. The effects of cracks are thus needed to be taken into account in the durability design of reinforced concrete structures. In the available publications, the experimental observations obtained from different researchers present large discrepancy on the quantitative effect of cracks on chloride diffusivity. And therefore the corresponding fitting formulas should have some limitations. In light of this, a unified quantitative relation between the chloride diffusion coefficient D_cr in crack and crack width w_cr is developed. The parameters in the proposed formula have their own physical meanings, and the corresponding curve of the formula is smooth without inflection point. The good agreement between the present theoretical results and the available test data illustrates the rationality of the developed formula. Finally, the chloride diffusivity in cracked concrete is studied and simulated by using FE method. The obtained simulation results are consistent with those in the available publications, indicating the effectiveness of the present method.