Influence of SAP Type on Early-crack Resistance and Drying Shrinkage Performance of Cement Mortar
WANG Ke1, HU Yuanyuan2, HE Rui1,*, ZHENG Suining1, ZHAO Jian2
1 School of Materials Science and Engineering, Chang'an University, Xi'an 710061, China 2 Yaobai Special Cement Technology R&D Co., Ltd., Xi'an 710100, China
Abstract: The absorbent properties of two different types of super absorbent polymer (SAP) (sodium acrylate and composite type of polymer) were studied, and the stable water loss rate was proposed as the evaluation index of SAP's water absorption dynamic behavior in cement pastes. The working performance of the modified cement mortar and its early anti-cracking and mechanical properties under different environments (standard curing environment and natural environment) were evaluated. SEM and XRD were adopted to explore the its micro modification mechanism. The results indicate that the absorption of SAP in saturated Ca(OH)2 solution exhibits a law of rapid increase, gradual decrease, and final stability. SAP can reduce the initial fluidity of cement mortar. At the same time, it can significantly alleviate the loss of fluidity of cement mortar with time. The addition of SAP can reduce the dry shrinkage of cement mortar and inhibit the formation and germination of early cracks in cement mortar panels. Both types of SAP can improve the early mechanical properties of cement mortar (before 7 d). Still, sodium acrylate type of polymer harms the mechanical properties of cement mortar at 28 d. The standard curing environment and the addition of SAP are conducive to the formation of AFt, C-S-H and CH. The hydration degree of cement is higher after SAP incorporation. The water release process of sodium acrylate type of polymer in the plastic stage of cement mortar is not conducive to the development of the microstructure of cement mortar. At the same time, a layer of inorganic-organic film is formed on the pore wall of the composite type of polymer after water release, which is conducive to reducing the negative effect of pores on cement mortar.
王柯, 胡元元, 何锐, 郑睢宁, 赵健. SAP类型对水泥砂浆早期抗裂和干缩性能的影响[J]. 材料导报, 2023, 37(23): 22050067-8.
WANG Ke, HU Yuanyuan, HE Rui, ZHENG Suining, ZHAO Jian. Influence of SAP Type on Early-crack Resistance and Drying Shrinkage Performance of Cement Mortar. Materials Reports, 2023, 37(23): 22050067-8.
1 Wu Xianguo,Wang Lei,Chen Hongyu,et al. Materials Reports,2022,36(17),115(in Chinese). 吴贤国,王雷,陈虹宇,等.材料导报,2022,36(17),115. 2 Shen D J,Liu C,Jiang J L,et al. Construction and Building Materials, 2020,258,120068. 3 He R, Wang T, Chen H X, et al. China Journal of Highway and Transport, 2020, 33(7),29 (in Chinese). 何锐, 王铜, 陈华鑫, 等 . 中国公路学报, 2020, 33(7),29. 4 Hu J Q. The study on anti-crack function and its mechanism of high performance concrete. Ph.D. Thesis, Wuhan University of Technology, China, 2002 (in Chinese). 胡建勤. 高性能混凝土抗裂性能及其机理的研究. 博士学位论文, 武汉理工大学, 2002. 5 He R, Tan Y W, Xue C, et al. China Sciencepaper, 2019, 14(4),464 (in Chinese). 何锐, 谈亚文, 薛成, 等 . 中国科技论文, 2019, 14(4),464. 6 Xiao S H. Study on shrinkage performance and early-age cracking analysis of floor concrete mixed with fiber and expansion agent. Master's Thesis, Tianjin University, China, 2018 (in Chinese). 肖树豪. 双掺纤维和膨胀剂地坪混凝土收缩性能和早期开裂分析. 硕士学位论文, 天津大学, 2018. 7 Yao Yan, Zhu Yu, Yang Yingzi. Construction and Building Materials, 2011, 28(1), 32 8 Zhang S Q, Lu Z B, Ang Y, et al. Journal of the Chinese Ceramic Society, 2020, 48(8), 1278 (in Chinese). 张守祺, 路振宝, 昂源, 等. 硅酸盐学报, 2020, 48(8), 1278. 9 Zhang Z L. Investigation on the shrinkage-reducing effect of super-absor-bent polymer in high-strength concrete and its mechanism. Master's Thesis. Tsinghua University, China, 2013 (in Chinese). 张珍林. 高吸水性树脂对高强混凝土早期减缩效果及机理研究. 硕士学位论文, 清华大学, 2013. 10 Schroefl C,Mechtcherine V,Vontobel P, et al. Cement and Concrete Research, 2015, 75, 1. 11 He Rui, Tan Yawen, Chen Huaxin, et al. Construction and Building Materials, DOI:2020,10.1016/j.conbuildmat.2020.119575. 12 Tan Yawen, Lu Xiaosong, He Rui, et al. Construction and Building Materials, 2021, 270, 121442. 13 Mechtcherine V, Secrieru E, Schröfl C. Cement and Concrete Research, 2015, 67, 52. 14 Kong X M, Lu Z B, Shi J, et al. Journal of the Chinese Ceramic Society, 2012, 40(11), 1553 (in Chinese). 孔祥明,路振宝,石晶, 等. 硅酸盐学报, 2012, 40(11), 1553. 15 Mo S X, Guo Y C, Tan X, et al. Journal of Highway and Transportation Research and Development, 2021, 38(8),1 (in Chinese). 莫石秀, 郭寅川, 覃潇, 等. 公路交通科技, 2021, 38(8), 1. 16 Yuan R Z. Cementitious materials science, Wuhan Industrial University Press, China, 1996(in Chinese). 袁润章. 胶凝材料学, 武汉工业大学出版社, 1996.
渝公网安备50019002502923号 版权所有：《材料导报》编辑部
2023, Vol. 37 
