海水干湿循环对初始损伤RC梁力学性能的影响
发布时间：2018-11-21 18:43
【摘要】：沿海环境下的钢筋混凝土(RC)结构处于荷载作用和环境作用同时存在的工作状态且在正常条件下会出现不同程度的荷载损伤。为了在实验室内模拟其工作状态,对RC梁试件施加幅值分别为0.3P_u、0.4P_u、0.5P_u、0.6P_u和0.7P_u(P_u为单调加载梁的极限荷载)的初始荷载造成不同程度的损伤,经历120次海水干湿循环作用后,进行单调加载试验测试剩余力学性能,并对梁试件钻芯取样测试不同位置及深度处混凝土的氯离子含量。试验结果表明,不同程度初始损伤RC梁经历120次海水干湿循环后,其屈服荷载、极限荷载和延性均随初始荷载幅值的增加而降低;与无损伤梁试件相比,当初始损伤荷载为0.4P_u时,梁试件的屈服荷载和极限荷载降幅分别为10.4%和7.9%,随着初始荷载增大,屈服荷载和极限荷载快速下降,当初始损伤荷载为0.7P_u时,屈服荷载和极限荷载降幅分别达33.7%和32.4%。氯离子含量测试结果表明,梁试件混凝土受拉区氯离子含量均大于受压区氯离子含量;当初始损伤荷载小于0.5P_u时,受拉钢筋表面混凝土的氯离子含量差别不大且小于0.1%,当初始损伤荷载为0.7P_u时,钢筋表面氯离子含量最大达到0.14%。可见,初始荷载损伤与海水干湿循环综合作用对RC梁力学性能及耐久性劣化影响显著。
[Abstract]:The reinforced concrete (RC) structure in coastal environment is in the working state of both loading and environmental action, and under normal conditions, there will be different degrees of load damage. In order to simulate its working state in the laboratory, the RC beam specimen was subjected to a magnitude of 0.3Pu / 0.4PuS / 0.5Pu respectively. The initial load of 0.6P_u and 0.7P_u (the ultimate load of a monotone loaded beam) caused varying degrees of damage. After 120 cycles of dry and wet seawater, the residual mechanical properties were tested by monotonic loading test. The chloride content of concrete at different positions and depths was measured by drilling core sampling of beam specimen. The experimental results show that the yield load, ultimate load and ductility of RC beams with different degrees of initial damage decrease with the increase of initial load amplitude after 120 dry and wet cycles in seawater. When the initial damage load is 0.4P_u, the yield load and ultimate load decrease by 10.4% and 7.9%, respectively. With the increase of initial load, the yield load and ultimate load decrease rapidly. When the initial damage load is 0.7P_u, the yield load and ultimate load decrease by 33.7% and 32.4% respectively. The results show that the chloride content in the tensile zone is higher than that in the compression zone. When the initial damage load is less than 0.5P_u, the chloride content of the concrete on the surface of the tensile steel bar is less than 0.1. When the initial damage load is 0.7P_u, the content of chloride ion on the surface of the steel bar reaches 0.14%. It can be seen that the combined effects of initial load damage and seawater dry and wet cycle have a significant effect on the mechanical properties and durability deterioration of RC beams.
【作者单位】： 北京航空航天大学交通科学与工程学院;华南理工大学亚热带建筑科学国家重点实验室;
【基金】：国家自然科学基金(51578031) 亚热带建筑科学国家重点实验室(2016ZA03)~~
【分类号】：TU37
[Abstract]:The reinforced concrete (RC) structure in coastal environment is in the working state of both loading and environmental action, and under normal conditions, there will be different degrees of load damage. In order to simulate its working state in the laboratory, the RC beam specimen was subjected to a magnitude of 0.3Pu / 0.4PuS / 0.5Pu respectively. The initial load of 0.6P_u and 0.7P_u (the ultimate load of a monotone loaded beam) caused varying degrees of damage. After 120 cycles of dry and wet seawater, the residual mechanical properties were tested by monotonic loading test. The chloride content of concrete at different positions and depths was measured by drilling core sampling of beam specimen. The experimental results show that the yield load, ultimate load and ductility of RC beams with different degrees of initial damage decrease with the increase of initial load amplitude after 120 dry and wet cycles in seawater. When the initial damage load is 0.4P_u, the yield load and ultimate load decrease by 10.4% and 7.9%, respectively. With the increase of initial load, the yield load and ultimate load decrease rapidly. When the initial damage load is 0.7P_u, the yield load and ultimate load decrease by 33.7% and 32.4% respectively. The results show that the chloride content in the tensile zone is higher than that in the compression zone. When the initial damage load is less than 0.5P_u, the chloride content of the concrete on the surface of the tensile steel bar is less than 0.1. When the initial damage load is 0.7P_u, the content of chloride ion on the surface of the steel bar reaches 0.14%. It can be seen that the combined effects of initial load damage and seawater dry and wet cycle have a significant effect on the mechanical properties and durability deterioration of RC beams.
【作者单位】： 北京航空航天大学交通科学与工程学院;华南理工大学亚热带建筑科学国家重点实验室;
【基金】：国家自然科学基金(51578031) 亚热带建筑科学国家重点实验室(2016ZA03)~~
【分类号】：TU37
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