减水剂作用下氯氧镁水泥中水分侵蚀行为
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摘要
氯氧镁水泥(MOC)的弱耐水性是限制其广泛应用的主要原因,通过吸水试验探索了MOC中水分侵蚀行为及改善措施。由MOC质量变化曲线得出在水分扩散过程中存在物质溶出时间节点,该点与5Mg(OH)_2·Mg Cl_2·8H_2O(P5)晶体耐水能力有关;添加减水剂后物质溶出节点时间后移,表明减水剂可改善MOC耐水性,毛细吸水系数结果表明减水剂提高了MOC的密实性;溶蚀动力学表明提高水泥耐水性的途径有降低水溶液温度、提高水溶液中氯化镁浓度、减少水解反应场所,而减水剂通过改变水化晶体形貌和提高水泥密实度等措施减少水解反应场所,提高了水泥耐水性;MOC混凝土性能试验结果表明,添加减水剂是改善MOC耐水性的有效途径之一。
The weak water resistance of magnesium oxychloride cement(MOC) is the main reason for limiting its wide application. In this paper, the water erosion behavior and improvement measures in MOC were explored by water absorption test. The material dissolution time point was found from the mass change curve, which was controlled by the water resistance of 5 Mg(OH)_2·MgCl_2·8 H_2O(P5) crystal. The point disappeared later after addition of the water reducer, which indicated that the water reducer improved the water resistance of the MOC. Capillary water absorption coefficient results showed that the water reducer improved the compactness of the MOC. The dissolution kinetics showed that the way to improve the water resistance of cement was to reduce aqueous solution temperature, increase the concentration of magnesium chloride in aqueous solution, and reduce the location of hydrolysis reaction. And the water reducer reduced the hydrolysis location by changing the morphology of the hydrated crystal and improving the cement compactness, and improves the water resistance of the cement. The performance test of MOC concrete indicated that water absorption test can characterize the water resistance of MOC and way.
The weak water resistance of magnesium oxychloride cement(MOC) is the main reason for limiting its wide application. In this paper, the water erosion behavior and improvement measures in MOC were explored by water absorption test. The material dissolution time point was found from the mass change curve, which was controlled by the water resistance of 5 Mg(OH)_2·MgCl_2·8 H_2O(P5) crystal. The point disappeared later after addition of the water reducer, which indicated that the water reducer improved the water resistance of the MOC. Capillary water absorption coefficient results showed that the water reducer improved the compactness of the MOC. The dissolution kinetics showed that the way to improve the water resistance of cement was to reduce aqueous solution temperature, increase the concentration of magnesium chloride in aqueous solution, and reduce the location of hydrolysis reaction. And the water reducer reduced the hydrolysis location by changing the morphology of the hydrated crystal and improving the cement compactness, and improves the water resistance of the cement. The performance test of MOC concrete indicated that water absorption test can characterize the water resistance of MOC and way.
引文
[1]张传镁,邓德华.氯氧镁水泥耐水性及其改善的研究[J].硅酸盐学报,1995(6):673-679.
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[3]WANG L,FENG K,CHEN X.Research on water resistance and mechanism of magnesium oxychloride cement foam concrete with compound modifiers[J].Journal of Functional Materials,2015,46(12):12009-12013.
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[7]陈雪霏,王路明.磷酸钠/苯丙乳液改善氯氧镁水泥耐水性的研究[J].混凝土,2017(6):76-79.
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[10]丁向群,张冷庆,孙艳丽.基于混料实验研究矿物外加剂对氯氧镁水泥性能的影响[J].沈阳建筑大学学报(自然科学版),2016,32(3):476-485.
[11]梁晓敏.硅灰对氯氧镁水泥耐水性影响机理研究[D].大连:大连理工大学,2017.
[12]王元宏.覆盖保护层可提高氯氧镁水泥耐水性[N].中国建材报,2011-04-21(004).
[13]余红发.镁水泥应用中新配料规则的理论与实践基础[J].菱镁砼信息,1993(4):1-15
[14]BA H,GUAN H.Influence of MgO/MgCl2,molar ratio on phase stability of magnesium oxychloride cement[J].Journal of Wuhan University of Technology(Materials Science Edition),2009,24(3):476-481.
[15]余红发.新型抗水氯氧镁水泥的研究[J].硅酸盐学报,1992(4):374-381.
[16]HU C,XU B,MA H,et al.Micromechanical investigation of magnesium oxychloride cement paste[J].Construction&Building Materials,2016,105:496-502.
[2]李颖,余红发,董金美,等.氯氧镁水泥的水化产物、相转变规律和抗水性评价方法的研究进展[J].硅酸盐学报,2013,41(11):1465-1473.
[3]WANG L,FENG K,CHEN X.Research on water resistance and mechanism of magnesium oxychloride cement foam concrete with compound modifiers[J].Journal of Functional Materials,2015,46(12):12009-12013.
[4]CAINE G E,ELLIS C W.Magnesium oxychloride cement:US,US7658795[P].2010.
[5]HU C,XU B,MA H,et al.Micromechanical investigation of magnesium oxychloride cement paste[J].Construction&Building Materials,2016,105:496-502.
[6]文静,余红发,吴成友,等.氯氧镁水泥水化历程的影响因素及水化动力学[J].硅酸盐学报,2013,41(5):588-596.
[7]陈雪霏,王路明.磷酸钠/苯丙乳液改善氯氧镁水泥耐水性的研究[J].混凝土,2017(6):76-79.
[8]张传镁,邓德华.铝酸盐矿物对氯氧镁水泥的影响[J].硅酸盐学报,1995(2):211-218.
[9]马慧.适用于氯氧镁水泥的聚羧酸减水剂合成及性能研究[D]西安:长安大学,2017.
[10]丁向群,张冷庆,孙艳丽.基于混料实验研究矿物外加剂对氯氧镁水泥性能的影响[J].沈阳建筑大学学报(自然科学版),2016,32(3):476-485.
[11]梁晓敏.硅灰对氯氧镁水泥耐水性影响机理研究[D].大连:大连理工大学,2017.
[12]王元宏.覆盖保护层可提高氯氧镁水泥耐水性[N].中国建材报,2011-04-21(004).
[13]余红发.镁水泥应用中新配料规则的理论与实践基础[J].菱镁砼信息,1993(4):1-15
[14]BA H,GUAN H.Influence of MgO/MgCl2,molar ratio on phase stability of magnesium oxychloride cement[J].Journal of Wuhan University of Technology(Materials Science Edition),2009,24(3):476-481.
[15]余红发.新型抗水氯氧镁水泥的研究[J].硅酸盐学报,1992(4):374-381.
[16]HU C,XU B,MA H,et al.Micromechanical investigation of magnesium oxychloride cement paste[J].Construction&Building Materials,2016,105:496-502.