Improving Pore Structure by Calcium Stearate to Reduce Water Sorptivity of Alkali-Activated Slag
LI Qing1,2, YANG Changhui2, CHEN Ping1, YANG Kai2,3, MING Yang1, ZHAO Yanrong1
1 Guangxi Key Laboratory of Engineering Structure and Building Energy Efficiency,College of Civil and Architectural Engineering, Guilin University of Technology, Guilin 541004, China 2 College of Materials Science and Engineering, Chongqing University, Chongqing 400045, China 3 School of Civil Engineering, University of Leeds, Leeds LS2 9JT, England
Abstract: The water sorptivity of alkali-activated slag cement is usually 3—5 times higher than that of ordinary Portland cement, which has serious negative effect on its durability. It is difficult to effectively reduce the water sorptivity of alkali-activated slag cement by traditional methods (such as increasing the compactness and adjusting the mix proportion). In this work, calcium stearate (CaSt) was used to improve the pore structure of alkali-activated slag, and calcium stearate hydrophobic film was introduced into the pore wall to reduce the water sorptivity of AAS. The effect of CaSt on the pore structure and water sorptivity of AAS was studied by means of MIP and SEM. The results show that CaSt can improve microstructure of AAS, reduce the hydration product defects, reduce the pore connectivity, and be able to form CaSt film on the surface of the hydration products, and thus the water sorptivity of AAS was reduced by about 80%. Meanwhile, it should be highlighted that in the AAS system, calcium stearate is not only a hydrophobic component, but also a pore structure modifier, making it have a good promotion potential.
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2021, Vol. 35 
