干湿交替下受弯开裂混凝土梁内氯离子侵蚀试验研究  

EXPERIMENTAL STUDY OF THE CHLORIDE ION EROSION IN FLEXURAL CRACKED CONCRETE BEAMS UNDER DRYING-WETTING CYCLES

作　　者：崔钊玮[1] 陆春华[1] 刘荣桂[1] 胡白香[1] 

机构地区：[1]江苏大学土木工程与力学学院,江苏镇江212013

出　　处：《工业建筑》2013年第10期97-101,147,共6页Industrial Construction

基　　金：国家自然科学基金项目(50908103;51278230);中国博士后科学基金项目(2012M511215);江苏大学高级专业人才科研基金项目(11JDG132)

摘　　要：：分析干湿交替对受弯开裂混凝土梁内氯离子侵蚀的影响，建立考虑表层对流区影响的氯离子等效扩散模型，并借助氯盐干湿循环试验对此模型进行验证。经过30个干湿循环后，采用快速氯离子含量检测（RCT）法，对各裂缝处及其周围混凝土内自由氯离子浓度进行测定。试验结果表明：干湿交替下，完好及受弯开裂混凝土的表层对流区深度在10～15mm；弯曲裂缝（宽度不大于0．339mm）截面处，对流区以内混凝土同一深度处自由氯离子浓度比完好处显著提高，且同一裂缝处的浓度分布符合扩散的基本规律；裂缝周围一定范围内混凝土的自由氯离子浓度随距裂缝横向距离的增大而减小，超过一定范围后，弯曲拉应力对混凝土氯离子渗透性能有一定的提高作用；经回归，裂缝处（宽度不大于0．339mm）等效氯离子扩散系数Dep（t）与裂缝宽度w之间存在二次函数关系。The influence of drying-wetting cycles on chloride penetration in flexural cracked concrete was analyzed, and an equivalent chloride diffusion model while considering the effect of surface convection zone was built. The model was verified by the experimental chloride drying-wetting cycles. After 30 cycles, the rapid chloride test （RCT） was used for measuring free chloride ion content of concrete at each cracked section and surrounding sections. Test results showed that under drying-wetting cycles, the depth of convection region in the sound and flexural cracked concrete was about from 10 to 15 mm; at flexural cracked sections, free chloride concentration of the same depth within convection zone increased significantly, and the concentration distribution accorded with the basic diffusion law; a certain range from cracks, free chloride ion content decreased as the horizontal distance from crack extended; beyond the range, bending tensile stress improved the chloride diffusion obviously; for the chloride diffusion in cracked concrete, there was an quadratic function relationship between the equivalent chloride diffusion coefficient of concrete and crack width.

关 键 词：钢筋混凝土结构 弯曲裂缝 氯离子 干湿交替 等效氯离子扩散系数 

分 类 号：TU375[建筑科学—结构工程]