Continuous Characterization of Pore Structure in Cement Paste

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Title: Continuous Characterization of Pore Structure in Cement Paste

Author(s): Zhiyong Liu, Sen Gao, Weiwei Chen, Yunsheng Zhang, and Cheng Liu

Publication: Materials Journal

Volume: 116

Issue: 6

Appears on pages(s): 117-129

Keywords: cement paste; hydration; pore structure; simulation

Date: 11/1/2019

Abstract:
Unlike traditional experimental testing, some procedures have been developed for the characterization of microstructures of cement-based materials. Based on the microstructure of the cement hydration model obtained from a digital image-based model, the parameters of pore structure were in-place continuously determined by CEMHYD3D. The characteristic parameters of pore include total porosity, the continuous pore, isolated pore, dead-end pore, connectivity, pore size distribution, specific surface area, and tortuosity. According to the combustion algorithm, the three-dimensional (3-D) voxel-erosion method, the mercury intrusion porosimetry simulation, the continuous PSD algorithm, and the random walk algorithm, the physical models are developed into program to obtain the characteristic parameters of pore structure evolution. The results show that the dead-end pores and the isolated pores begin to decrease after the continuous pores disappear. The pore size distribution of the pore structure is calculated with finer resolution. The water-cement ratio (w/c) and hydration degree have a significant effect on the specific surface area of the pores. With the increase of the degree of hydration, the tortuosity of the pore structure increases gradually. Finally, the simulation results are compared to the experimental values and the literature data that have a good agreement.