A novel lattice model to predict chloride diffusion coefficient of unsaturated cementitious materials based on multi-typed pore structure characteristics

A novel lattice model to predict chloride diffusion coefficient of unsaturated cementitious materials based on multi-typed pore structure characteristics

Tong, Liang-yu (Shanghai Jiao Tong University)
Xiong, Qing Xiang (Shanghai Jiao Tong University)
Zhang, Zhidong (ETH Zürich)
Chen, Xiangsheng (Shenzhen University)
Ye, G. (TU Delft Materials and Environment)
Liu, Qing feng (Shanghai Jiao Tong University)

2023

This paper develops a novel lattice diffusive model to quantitatively study the chloride diffusion coefficient in unsaturated cementitious materials, in which the pore voxels are redistributed to make a better representation of a real microstructure of hardened cement paste. Considering the hierarchical microstructure and different drying-wetting cycles, water distributions in multiscale pore structures are modelled and the structure characteristics of water-filled pores, including water connectivity, water tortuosity and effective porosity, are computationally extracted based on that. A lattice diffusion network is established to predict relative chloride diffusion coefficient by combining the effect of both water saturation degree and pore structure characteristics. The predicted results are validated against experimental data, and a concise analytical equation is proposed to predict the relative chloride diffusion coefficient. The equation indicated that the relative chloride diffusion coefficient is proportional to water connectivity but inversely proportional to the square of water tortuosity. Besides, the lattice model's quantitative results reveal that the water connectivity and water tortuosity are highly related to pre-water loading processes, and influenced by the gel pore fraction, which in turn will affect the relative chloride diffusion coefficient. Compared with existing equations and non-redistributed models, the present model could improve the prediction accuracy significantly.

Cementitious materials
Chloride diffusion
Drying-wetting process
Lattice model
Pore structure

http://resolver.tudelft.nl/uuid:f03a92f6-37ee-4ac5-97cd-2501401fd19f

https://doi.org/10.1016/j.cemconres.2023.107351

2024-06-07

0008-8846

Cement and Concrete Research, 176

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Liang-yu Tong, Qing Xiang Xiong, Zhidong Zhang, Xiangsheng Chen, G. Ye, Qing feng Liu