Meso-scale modeling of chloride diffusivity in mortar subjected to corrosion-induced cracking

This paper presents a methodology for numerically simulating the chloride diffusivity in mortar subjected to corrosion-induced cracking with the aid of X-ray microcomputed tomography (X-ray mu CT). In the research, the mortar sample with embedded steel rod was subjected to accelerated corrosion and then scanned by X-ray mu CT at consecutive corrosion periods of 0, 1,000, and 2,000 minutes. Upon the scanned CT images, a meso-scale model consisting of multiple material phases with their intrinsic structures was built up and implemented into a finite element method for diffusion simulation. In the numerical simulation, the effects of multiple phases (void, crack, aggregate, rust, and interfacial transition zone between cement and aggregate) on the chloride diffusion of mortar are studied. Since the X-ray mu CT facilitates accurate local material information in time-dependent and in situ manner, the diffusivity of mortar under different corrosion time and its spatial distribution characteristics (e.g., at different locations from the mortar surface) can be evaluated.

Automated summary

This study presents a methodology for numerical simulation of chloride diffusivity in mortar subjected to corrosion-induced cracking using X-ray microcomputed tomography. The effects of multiple material phases on chloride diffusion are studied, and accurate local material information allows evaluation of diffusivity and spatial distribution characteristics of mortar under different corrosion times.