Effects of Citric Acid on Hydration Process and Mechanical Properties of Thermal Decomposed Magnesium Oxychloride Cement
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2014年第1期
论文作者：文静 余红发 LI Ying WU Chengyou DONG Jinmei
文章页码：114 - 118
摘 要：In order to make full use of salt lake magnesium resources and improve the strength of the thermal decomposed magnesium oxychloride cement（TDMOC）, the effects of citric acid on the hydration process and mechanical properties of TDMOC was studied. The hydration heat release at initial 24 h and strengths at 3, 7, and 28 days of TDMOC specimens were conducted. The hydration products and paste microstructure were analyzed by XRD, FT-IR and SEM, respectively. The results showed that citric acid can not only reduce the 24 h hydration heat release and delay the occurring time of second peak of TDMOC, but also produce more 5Mg（OH）2·MgCl 2·8H2O and less Mg（OH）2 in hydration process of TDMOC. More perfect and slender crystals were observed in the microstructure of the TDMOC pastes with citric acid. The results demonstrated that citric acid as an additive of TDMOC can decrease the hydration heat release and increase the compressive strength and flexural strength of TDMOC. The possible mechanism for the strength enhancement was discussed.
文静1，余红发1,2,3，LI Ying1，WU Chengyou1，DONG Jinmei1
1. Qinghai Institute of Salt Lakes,Chinese Academy of Sciences2. Civil Engineering Institute, Qinghai University3. Department of Civil Engineering, Nanjing University of Aeronautics and Astronautics
摘 要：In order to make full use of salt lake magnesium resources and improve the strength of the thermal decomposed magnesium oxychloride cement（TDMOC）, the effects of citric acid on the hydration process and mechanical properties of TDMOC was studied. The hydration heat release at initial 24 h and strengths at 3, 7, and 28 days of TDMOC specimens were conducted. The hydration products and paste microstructure were analyzed by XRD, FT-IR and SEM, respectively. The results showed that citric acid can not only reduce the 24 h hydration heat release and delay the occurring time of second peak of TDMOC, but also produce more 5Mg（OH）2·MgCl 2·8H2O and less Mg（OH）2 in hydration process of TDMOC. More perfect and slender crystals were observed in the microstructure of the TDMOC pastes with citric acid. The results demonstrated that citric acid as an additive of TDMOC can decrease the hydration heat release and increase the compressive strength and flexural strength of TDMOC. The possible mechanism for the strength enhancement was discussed.
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