Attack of Limestone Cement-based Material Exposed to Magnesium Sulfate Solution at Low Temperature
来源期刊：Journal Of Wuhan University Of Technology Materials Science Edition2014年第3期
论文作者：张风臣 WU Shengxing FANG Yonghao ZHOU Jikai LI Zhonghua
文章页码：507 - 512
摘 要：Limestone in cement could be a source of CO 3 2- needed for thaumasite formation which will result in thaumasite form of sulfate attack（TSA） probably. TSA has more deterioration than ettringite or gypsum form of sulfate attack because it targets the calcium silicate hydrates（C-S-H） which is the main binder phase in all Portland cement-based materials. By means of physical and mechanical property testing as well as erosion phases analysis, magnesium sulfate attack of cement-based material containing 35% limestone powder by mass at 5 ± 2 ℃ is investigated. The compressive strength and fl exural strength of mortar specimen immersed in MgSO 4 solution increase firstly, then decrease rapidly with the immersing age. Relative dynamic elastic modulus of mortar specimen changes in a phased process. After immersing in MgSO 4 solution for 15 weeks, the main erosion phases in paste specimen change from four phases compounds, three phases compounds to two phases compounds from surface to inside. Deterioration course of limestone cement-based material exposed to magnesium sulfate aggressive environment appears progressive damage layer by layer, and every layer probably suffers four stages, which are property strengthening stage, initial degradation stage, thaumasite formation stage and cementation loss stage, respectively.
张风臣，WU Shengxing，FANG Yonghao，ZHOU Jikai，LI Zhonghua
College of Mechanics and Materials, Institute of Engineering Materials, Hohai University
摘 要：Limestone in cement could be a source of CO 3 2- needed for thaumasite formation which will result in thaumasite form of sulfate attack（TSA） probably. TSA has more deterioration than ettringite or gypsum form of sulfate attack because it targets the calcium silicate hydrates（C-S-H） which is the main binder phase in all Portland cement-based materials. By means of physical and mechanical property testing as well as erosion phases analysis, magnesium sulfate attack of cement-based material containing 35% limestone powder by mass at 5 ± 2 ℃ is investigated. The compressive strength and fl exural strength of mortar specimen immersed in MgSO 4 solution increase firstly, then decrease rapidly with the immersing age. Relative dynamic elastic modulus of mortar specimen changes in a phased process. After immersing in MgSO 4 solution for 15 weeks, the main erosion phases in paste specimen change from four phases compounds, three phases compounds to two phases compounds from surface to inside. Deterioration course of limestone cement-based material exposed to magnesium sulfate aggressive environment appears progressive damage layer by layer, and every layer probably suffers four stages, which are property strengthening stage, initial degradation stage, thaumasite formation stage and cementation loss stage, respectively.
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