Title: Random Walk Algorithm for Chloride Diffusivity of Concrete

Author(s): Jian-Jun Zheng, Jian Zhang, Xin-Zhu Zhou, Jia-Wei Wang, and Yan-Wen Ding

Publication: Materials Journal

Volume: 117

Issue: 2

Appears on pages(s): 79-86

Keywords: chloride diffusivity; equivalent aggregate model; random walk algorithm; spheroidal aggregate

DOI: 10.14359/51720295

Date: 3/1/2020

Abstract:
This paper aims at developing a numerical algorithm for the chloride diffusivity of concrete containing spheroidal aggregates. In the algorithm, spheroidal aggregates of various sizes are generated for a given sieve curve and placed into a cubic simulation element. The mesostructure of concrete is reconstructed by surrounding each aggregate with an interfacial transition zone (ITZ). To increase the computational efficiency, an equivalent aggregate model (EAM) is built and the equivalent ITZ thickness and chloride diffusivity are derived analytically. The chloride diffusivity of concrete is estimated with the random walk algorithm. Finally, the validity of the numerical algorithm is verified with the experimental results obtained in this paper and collected from the literature and the effect of aggregate aspect ratio on the chloride diffusivity is evaluated quantitatively.