Volume Deformation and Hydration Behavior of Ordinary Portland Cement/Calcium Sulfoaluminate Cement Blends

Guangxiang Ji; Hafiz Asad Ali; Keke Sun; Dongxing Xuan; Xiaoqin Peng; Jingjun Li

doi:10.3390/ma16072652

Volume Deformation and Hydration Behavior of Ordinary Portland Cement/Calcium Sulfoaluminate Cement Blends

Materials (Basel). 2023 Mar 27;16(7):2652. doi: 10.3390/ma16072652.

Authors

Guangxiang Ji¹, Hafiz Asad Ali², Keke Sun^{2

3}, Dongxing Xuan², Xiaoqin Peng⁴, Jingjun Li³

Affiliations

¹ Department of Hydraulic Engineering, Tsinghua University, Beijing 100084, China.
² Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hong Kong 999077, China.
³ School of Civil Engineering, Inner Mongolia University of Science and Technology, Baotou 014010, China.
⁴ College of Materials Science and Engineering, Chongqing University, Chongqing 400044, China.

Abstract

Blends of ordinary Portland cement (OPC) and calcium sulfoaluminate (CSA) cement can be used to adjust the properties of cement for specific applications. In this study, CSA cement was used as a shrinkage-compensating admixture to improve the hydration behavior and performance (compressive strength and drying shrinkage) of OPC; the expansion behavior of the blended cement mortar was evaluate based on the saturation index of ettringite. The experimental results showed that incorporating CSA cement resulted in a delayed effect on the hydration of C₃S, shortened the induction periods of the blended cement and decreased the setting time. The CSA cement also improved the early compressive strength and drying shrinkage of the OPC due to its compact microstructure. The drying shrinkage of the OPC mortar decreased by 27.8% when 6% CSA cement was used, but the formation of microcracks due to expansion could negatively impact its late compressive strength development and associated pore structures of the blends when the replacement content of CSA cement exceeded 6 wt.%. The results relevant to the expansion behavior of the CSA cements could induce crystallization stress, enhancing its resistance against shrinkage cracking.

Keywords: calcium sulfoaluminate cement; hydration; microstructure; ordinary Portland cement; volume deformation.

Grants and funding

This research was funded by Key Project of Open Fund of Shaanxi Key Laboratory of Safety and Durability of Concrete Structures grant number SZ02301, and the key R&D and Achievement Transformation Projects of the Inner Mongolia Autonomous Region (2022YFHH0118) and Natural Science Foundation of China (51678093), were gratefully acknowledged.