Effects of Bending Stress on the Microstructure and Properties of Hydrated Cement Paste

 

Tao Sun

Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan 430070, P.R China
*Corresponding author;e-mail: sunt@whut.edu.cn

Xinping Li

Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan 430070, P.R China

Zhonghe Shui

School of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, P.R China

Weiwei Han

Key Laboratory of Roadway Bridge & Structure Engineering, Wuhan University of Technology, Wuhan 430070, P.R China

 

 ABSTRACT

Usually the sample was placed on research under standard conditions after demoulding, with little or less state of stress. But, most were in a state of stress. In this paper, samples imposed by 30%I8 bending loads were studied. In order to study the microstructure and properties of hardened cement paste specimens, XRD for qualitative analysis, TG-DSC for quantitative analysis and BET for specific surface, and so on, were used. The results showed the bending stress would not change the cement hydration product type but instead the morphology, distribution and abundance of the hydration products. And the hydration degree existed: compression zone> tension zone> blank zone, both the tensile stress and the compressive stress promoted the hydration rate, and the compressive stress played a greater role than the tensile stress. In addition the total pore volume and the specific surface area in the compression zone were greater than that of the tensile zone.

Keywords: Bending stress; hydrated cement paste; microstructure; specific surface area; pore size distribution.

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