混凝土中的裂缝对氯盐侵蚀作用的影响  

Effect of cracks in concrete on chloride penetration

作　　者：张君[1] 居贤春[1] 公成旭[1] 

机构地区：[1]清华大学土木工程系结构工程与振动教育部重点实验室,北京100084

出　　处：《哈尔滨工程大学学报》2010年第6期720-724,共5页Journal of Harbin Engineering University

基　　金：国家自然科学基金资助项目(50878119);交通部西部交通建设科技资助项目(200631822302-06)

摘　　要：为了研究裂缝对氯离子侵蚀作用的影响,采用弯曲试验预先在混凝土梁中产生宽度不等的弯曲裂缝,然后通过3%NaC l盐溶液浸泡一定龄期后钻心取样,测定裂缝处混凝土内氯离子含量.试验结果表明,混凝土中裂缝对氯盐环境下氯离子渗透的影响是显著的,裂纹大大加快了氯离子的侵蚀速度.裂纹处（裂缝宽度120-500μm）氯离子浓度为相同浸泡龄期无裂纹处的2-3倍.浸泡30 d时,裂纹处氯离子含量随裂缝宽度增大而增加,60 d时氯离子含量基本达到饱和,不受裂缝宽度影响,此时氯离子含量受浸泡深度影响不大.未开裂混凝土,即使氯盐浸泡60 d,氯离子含量随浸泡深度仍呈逐渐减少的趋势.The effect of cracks in concrete on chloride penetration was investigated by measuring chloride levels in pre-induced flexural cracks in concrete beams.The bottoms of cracked beams were soaked in a 3% NaCl solution.The content of Cl-1 in the concrete at the location of the cracks was determined by drilling powder samples with an electric hammer.The experimental results showed that the influence of cracks on chloride penetration is very significant.The content of chloride in the concrete was 2 to 3 times higher at the location of the cracks（120-500 μm wide） compared to places without cracks.The chloride content at the location of cracks in the concrete increased with increased crack width for specimens soaked 30 days.After 60 days of soaking,the chloride content became almost constant,with minimal changes with penetration depth,indicating a saturated state was achieved.For concrete without cracks chloride content decreased with increased penetration depth even after 60 days of soaking in chloride.

关 键 词：混凝土 裂缝 氯离子渗透 耐久性 

分 类 号：TU528[建筑科学—建筑技术科学]