地下混凝土结构硫酸盐及氯盐侵蚀的耐久性实验  

Underground concrete structure exposure to sulfate and chloride invading environment

作　　者：陈晓斌[1,2] 唐孟雄 马昆林[1] 

机构地区：[1]中南大学土木建筑学院,湖南长沙410075 [2]广州市建筑科学研究院,广东广州510440

出　　处：《中南大学学报（自然科学版）》2012年第7期2803-2812,共10页Journal of Central South University:Science and Technology

基　　金：国家自然科学基金资助项目(50908233);中国博士后科学基金资助项目(20080440996);广州市建设科技基金资助项目(2007Y0091)

摘　　要：针对硫酸盐及氯盐共同侵蚀下混凝土中SO 42-和Cl-的扩散规律和性能劣化特征进行室内模拟实验研究。研究结果表明：硫酸根与氯离子在混凝土中扩散短期内起到相互牵制效应,SO 24-与水泥水化产物的合成物和Cl-生成的F盐堵塞孔隙,延缓侵蚀离子扩散。硫酸根与氯离子共同侵蚀下,抗侵蚀系数和抗渗透性能先增加后减小,同时水灰比、粉煤灰对抗侵蚀性及渗透性影响明显。实验研究指出物理侵蚀发生的最明显温度在21~24℃之间,缓解温度在30~35℃之间,较小的相对湿度（RH为45%）、较高的温度变化加快了硫酸盐物理侵蚀。微观测试和分析表明,Friede盐、大量钙矾石（AFt）以及硫酸钠结晶物,导致了混凝土内部结构松散劣化,Na,S和Cl等侵入元素的存在说明有害物质侵入痕迹。Series of simulation tests were executed to analyze sulfate ions and chloride ions diffusion and concrete＇s mechanical deterioration when the sulfate and chloride synchronously invade environments of underground structure. During the short period, there exists obvious interaction between sulfate ions and chloride ions distribution, for the chemical compounds of sulfate ions, chloride ions and cement hydration jam some micro porosity of specimens, which retard the ions invading. With exposure to the sulfate and chloride synchronously invading, the resist coefficients of erosion and penetrability increase first and then decrease, which is also evidently affected by water cement ratio and additive flyash. The temperature of physical erosion as sodium sulfate crystallization form is between 21 and 24 ℃, then the erosion decreasing temperature is between 30 and 35 ℃. The low relative humidity （RH 45%） and temperature inflation can quicken the physical erosion. The microstructure analysis shows that there are lots of Friede salt, Ettringite （Aft） and sodium sulfate crystallization inside specimens, which causes concrete loose internal structure and mechanical deterioration. The existing of Na, S and C1 indicates the invading track of chloride ions and chloride ions distribution in specimens .

关 键 词：结构耐久性 城市地下结构 硫酸盐侵蚀 氯盐侵蚀 扩散规律 

分 类 号：TU471.8[建筑科学—结构工程]