Study on Regulation Mechanism of Triethanolamine to Liquid Alkali-free Accelerator on ‘Accelerating-Inhibiting' of Early Hydration of Cement
LIU Xiao1,*, XIE Hui1, LUO Qifeng1, WANG Ziming1, CUI Suping1, GUO Jinbo2, ZHANG Guanhua2
1 Key Laboratory of Advanced Functional Materials, Ministry of Education, Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, China 2 Liaoning Provincial Transportation Planning and Design Institute Co., Ltd., Shengyang 110111, China
Abstract: Triethanolamine (TEA), as a commonused component in cement concrete for early strength, which can significantly promote the development of early strength. In recent years, with the rapid development of shotcrete and liquid alkali-free accelerator, triethanolamine has been widely used due to its excellent early-strength characteristics. However, the performance of accelerator prepared from triethanolamine under different conditions are not the same or even the opposite. Its influence law and action mechanism on early hydration of cement need to be clarified. In this study, liquid alkali-free accelerator with different proportions of TEA was prepared. The influence of TEA in the alkali-free accelerator on the early hydration of cement was investigated in detail from the aspects of setting time, early strength, hydration exothermic behavior, hydrate phase and thermal analysis. The results show that when TEA accounted for 0.25% of the mass of alkali-free accelerator, the setting time was the shortest, the initial setting was 109 s, the final setting was 324 s, and the strength was the highest at 1 d, reaching 12.32 MPa, which meets the national standard requirements of accelerator for shotcrete. TEA can accelerate the accelerating effect of alkali-free accelerator on early hydration of cement at low dosage, while it can significantly weaken and inhibit early hydration of cement at high dosage. In addition, the complexation mec-hanism between TEA and aluminum phase was studied by means of conductivity and nuclear magnetic hydrogen spectroscopy, and the regulation mechanism of TEA to liquid alkali-free accelerators on the ‘accelerating-inhibiting' early hydration of cement was revealed:(ⅰ) when the content of TEA is low, metaaluminate ions complex with TEA and participate in accelerating the early hydration of C3A;(ⅱ) high TEA content will produce a large amount of ettringite and TEA-Ca complex, which will cover the surface of C3A and inhibit hydration. This study systematically explores the influence and regulation mechanism of liquid alkali-free accelerator with different TEA contents on early hydration of cement, which provides an important research basis and scientific guidance for the development of high-performance liquid alkali-free accelerator.
刘晓, 谢辉, 罗奇峰, 王子明, 崔素萍, 郭金波, 张冠华. 三乙醇胺对液体无碱速凝剂“促-抑”水泥早期水化的调控机理研究[J]. 材料导报, 2023, 37(9): 21100165-6.
LIU Xiao, XIE Hui, LUO Qifeng, WANG Ziming, CUI Suping, GUO Jinbo, ZHANG Guanhua. Study on Regulation Mechanism of Triethanolamine to Liquid Alkali-free Accelerator on ‘Accelerating-Inhibiting' of Early Hydration of Cement. Materials Reports, 2023, 37(9): 21100165-6.
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