A Three-Dimensional Random Walk Algorithm for Estimating the Chloride Diffusivity of Concrete

Materials

Jian Zhang¹  Bin Zeng²  Hua Rong²  Xin-Zhu Zhou³  Jian-Jun Zheng³  Cong-Yan Zhang⁴ 

[1] Jiyang College, Zhejiang Agriculture and Forestry University, Zhuji 311800, China;Research Department of Science and Technology, Central Research Institute of Building and Construction, Metallurgical Group Corporation of China, Beijing 100088, China;School of Civil Engineering, Zhejiang University of Technology, Hangzhou 310023, China;Yuanpei College, Shaoxing University, Shaoxing 312000, China;

关键词: concrete;    chloride diffusivity;    EAM;    RWA;    spherical aggregate;   

DOI  :  10.3390/ma13245700

来源: DOAJ

【 摘 要 】

The chloride diffusivity of concrete is an important parameter for assessing the long-term durability of coastal concrete structures. The purpose of this paper is to present a three-dimensional random walk algorithm (RWA) for estimating the chloride diffusivity of concrete. By analyzing the size distribution of aggregates, the equivalent interfacial transition zone (ITZ) thickness is derived in an analytical manner. Each aggregate is combined with the surrounding ITZ to construct an equivalent aggregate model (EAM) and the chloride diffusivity is formulated. It is found that the equivalent ITZ thickness decreases with the increase of practical ITZ thickness and aggregate volume fraction. The aggregate gradation influences the equivalent ITZ thickness to a certain extent. The relative chloride diffusivity of the equivalent aggregate is almost directly and inversely proportional to the equivalent ITZ thickness and the aggregate radius, respectively. The numerical results show that, when the EAM is adopted, the computational time is greatly reduced. With the EAM, concrete can be modeled as a two-phase material and the chloride diffusivity is estimated by applying the RWA. It is shown that, with the increase of mean square displacement and number of Brownian particles, the average chloride diffusivity of concrete approaches a stable value. Finally, through comparison with experimental data, the validation of the RWA is preliminarily verified.

【 授权许可】

Unknown