水泥基材料在硫酸盐结晶侵蚀下的劣化行为  

Deterioration behaviors of sulfate crystallization attack on cement-based material

作　　者：马昆林[1] 谢友均[1] 龙广成[1] 朱岱力[2] 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075 [2]湖南工业职业技术学院机械工程系,湖南长沙410208

出　　处：《中南大学学报（自然科学版）》2010年第1期303-309,共7页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(50678174)

摘　　要：采用水泥砂浆在硫酸钠溶液中半浸泡的试验方法,测试不同配比的砂浆外观形貌、抗压抗折强度等宏观性能,并通过分析砂浆孔结构、孔隙率、微观形貌以及腐蚀产物,探讨半浸泡条件下,硫酸盐结晶对砂浆造成侵蚀破坏的影响因素。研究结果表明:在半浸泡条件下,砂浆表面所生成的白色硫酸钠晶体含量与砂浆的水灰比和掺入的矿物掺合料有关;随着半浸泡时间增加,水泥砂浆表面逐渐被剥蚀,抗压抗折强度先增大后逐渐降低;砂浆中孔径在30nm以上的孔是导致砂浆受到侵蚀的主要孔隙;大量结晶物聚集在砂浆孔隙中并结晶膨胀造成了砂浆的物理结晶侵蚀;掺入适量的活性矿物掺合料能有效降低砂浆中孔径在30nm以上毛细孔的数量,提高砂浆抗硫酸盐结晶侵蚀能力。The changes of compressive strength, flexural strength and appearance of cement mortar were tested by partial soaking experiment with sodium sulfate solution. And influence factors of sodium sulfate solution attack on cement mortar were investigated through analyzing the changes of pore structure, porosity and corrosive products in the process of crystallization attack. The results show that under partial soaking condition, the quantity of white sodium sulfate crystal in cement mortar surface is related to the mass ratio of water and C and the addition of mineral admixture. With the increase of partial soaking time, surface of cement mortar is denuded gradually, and compressive and flexural strength increase first and then decrease. Pores with diameter above 30 nm are the main pore attacked by salt solution. Lots of sodium sulfate solution accumulate in pore of cement mortar and crystallization takes place, resulting in physical attack on cement mortar. The addition of proper mineral admixture into cement mortar can decrease the proportion of pore with diameter above 30 nm, so the capability of resisting sulfate crystallization attack is improved.

关 键 词：混凝土 硫酸盐 物理侵蚀 劣化行为 耐久性 

分 类 号：TU528[建筑科学—建筑技术科学]