掺石灰石粉水泥胶砂低温硫酸盐侵蚀破坏与机理  

Deterioration Mechanism of Limestone Filler Cement Mortar Exposed to Sulfate Attack at Lower Temperature

作　　者：王政[1] 高小建[1] 马保国[2] 

机构地区：[1]哈尔滨工业大学材料科学与工程学院,黑龙江哈尔滨150006 [2]武汉理工大学材料科学与工程学院,湖北武汉430070

出　　处：《沈阳建筑大学学报（自然科学版）》2008年第1期95-99,共5页Journal of Shenyang Jianzhu University：Natural Science

基　　金：国家自然科学基金项目(50408016);国家863计划资助项目(23005AA332010)

摘　　要：目的研究混凝土碳硫硅酸钙侵蚀(TSA)破坏机理,以提高混凝土耐久性.方法测试水泥胶砂在(5±1)℃,且质量分数为2%的MgSO4溶液中浸泡1 a期间的外观与强度变化,利用X-射线衍射仪,傅里叶红外光谱仪,扫描电子显微镜分析了浸泡1 a各砂浆的矿物成分与微观结构.结果在低温硫酸盐环境下,少量石灰石粉的掺入可改善水泥砂浆的抗侵蚀性能,而掺量较多时反而会加速砂浆的侵蚀破坏过程.在低温硫酸盐溶液中浸泡1 a后,纯水泥砂浆的破坏形式为表面开裂、脱落,在表层砂浆中生成了大量的钙矾石和石膏晶体;掺30%石灰石粉的砂浆主要表现为表面软化、浆化,腐蚀产物以碳硫硅酸钙和石膏晶体为主,为典型的碳硫硅酸钙侵蚀(TSA)破坏.结论使用大量石灰石填料或骨料时,水泥基材料在低温硫酸盐环境下可能发生以碳硫硅酸钙为主要腐蚀产物的TSA破坏.Cement mortars containing 0 to 30 % mass of limestone filler were immersed in 2% rmgnesiurn sulfate solution at 5 ± 10℃, their appearance and strength development with immersion times were measured at intervals. X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy were used to analyze the mineral composite and microstructure of the mortars after 1 year of immersion. The results show that the addition of a lower content of limestone filler improves the mortar＇s resistance to sulfate attack at lower temperature.But the sulfate attack of mortar is accelerated when adding a higher content of limestone filler. The surface cracking and spallation occurs in the pure cement mortar specimen after 1 year of immersion to the sulfate solution and a lot of ettringite and gypsum forms in the attacked mortar. On the other hand, the surface layer of the 30 % limestone filler mortar becomes soft and mushy, both thaumasite and gypsum were identified in the residual mortar, therefore the mortar undergoes the typical thaumasite form of sulfate attack.

关 键 词：水泥基材料 石灰石粉 硫酸盐侵蚀 低温 碳硫硅酸钙 

分 类 号：TU528.01[建筑科学—建筑技术科学]