Abstract: Shrinkage reducing admixture is widely used to restrain the shrinkage of concrete, but it will hinder the hydration process of cement. It is of practical significance to explore the source of this negative effect. Polyether type shrinkage reducing admixture is the most widely used shrinkage reducing admixture at present. Taking this kind of shrinkage reducing admixture as the research object. By testing the hydration heat and hydration degree of cement, the surface tension of liquid, the compressive strength and setting time of mortar, the ion concentration in paste pore solution, the maximum solubility and dissolution rate of sulfate, the interaction mechanism between shrinkage reducing admixture and cement was discussed. The results show that the addition of shrinkage reducing admixture can significantly reduce the mechanical properties of mortar and the hydration degree of cement, but the negative effect will gradually decrease with the increase of age, and the setting time of mortar and the hydration heat of cement will also be reduced by adding shrinkage reducing admixture. The decrease of hydroxyl radical concentration, maximum solubility and dissolution rate of sulfate in pore solution is the reason for this phenomenon. There is a bilinear relationship between the surface tension of pore solution and deionized aqueous solution containing shrinkage reducing admixture and the concentration of shrinkage reducing admixture. After the inflection point, the increase of the concentration of shrinkage reducing admixture has no obvious effect on the surface tension, and the delayed addition of shrinkage reducing admixture alleviates its adverse effect on cement hydration and reduces the decrease of mortar strength.
1 Chen B C, Wei J G, Su J Z, et al. Journal of Architecture and Civil Engineering, 2019, 36(2), 10(in Chinese). 陈宝春, 韦建刚, 苏家战, 等. 建筑科学与工程学报, 2019, 36(2), 10. 2 Zeng G D, Zhou M, Yang T Y, et al. Concrete, 2020(3), 105(in Chinese). 曾国东, 周敏, 杨腾宇, 等. 混凝土, 2020(3), 105. 3 Ma Y P, Zhu B R, Tan M H. Journal of Building Materials, 2003(1), 20(in Chinese). 马一平, 朱蓓蓉, 谈慕华. 建筑材料学报, 2003(1), 20. 4 Lu J Y, Wang L, Yong H, et al. Material Reports, 2020, 34(S2), 1618(in Chinese). 卢京宇, 王林, 雍涵, 等. 材料导报, 2020, 34(S2), 1618. 5 Zuo W Q, Tian Q, Ran Q P, et al. Journal of Building Materials, 2016, 19(3), 503(in Chinese). 左文强, 田倩, 冉千平, 等. 建筑材料学报, 2016, 19(3), 503. 6 Zhan P M, He Z H. Construction and Building Materials, 2019, 201, 676. 7 Zhang W Y, Lin H X, Wang S, et al. Bulletin of the Chinese Ceramic Society, 2022, 41(2), 526(in Chinese). 张文艳, 林华夏, 王帅, 等. 硅酸盐通报, 2022, 41(2), 526. 8 Rui Y, Spiesz P, Brouwers H . Cement and Concrete Research, 2014, 40(7), 187. 9 Wyrzykowski M, Lura P, Bajare D, et al. Cement and Concrete Research, 2015(6), 76. 10 Li Q, Chen G J. Material chemistry(The second edition), Higher Education Press, China, 2010(in Chinese). 李奇, 陈光巨. 材料化学. (第2版), 高等教育出版社, 2010. 11 Rajabipour F, Sant G, Weiss J. Cement and Concrete Research, 2008, 38(5), 606. 12 Penko M. Some early hydration processes in cement paste as monitored by liquid phase composition measurements. Ph. D. Thesis, Purdue University, 1983. 13 James B, Ivan O. Hydration, setting and hardening of portland cement, Butterworth-Heinemann, 2019. 14 Wei D B, Ding M, Ren G B, et al. Material Reports, 2018, 32(S2), 492(in Chinese). 魏定邦, 丁民, 任国斌, 等. 材料导报, 2018, 32(S2), 492. 15 Wang Q, Li M Y, Shi M X. Journal of the Chinese Ceramic Society, 2014, 42(5), 629(in Chinese). 王强, 黎梦圆, 石梦晓. 硅酸盐学报, 2014, 42(5), 629. 16 Rongbing B, Jian S. Cement and Concrete Research, 2005, 35(3), 445.
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2024, Vol. 38 
