持续荷载和环境耦合作用下钢筋混凝土抗氯盐侵蚀试验研究  

Experimental study on resistance of reinforced concrete to chloride salt erosion under continuous loading and environmental coupling

作　　者：卢凯 薛文[1] 徐锦超 周文建 LU Kai;XUE Wen;XU Jinchao;ZHOU Wenjian(Zhejiang University of Science and Technology,Hangzhou 310000,China)

机构地区：[1]浙江科技学院,浙江杭州310000

出　　处：《混凝土》2021年第2期4-7,12,共5页Concrete

基　　金：国家自然科学基金“持续拉应力状态下氯离子在非饱和开裂混凝土中的传输机理研究”(51608484)。

摘　　要：沿海混凝土结构长期处于持续荷载和侵蚀环境的耦合作用中。试验设计可持续施加拉/压应力的加载装置,对13根混凝土梁施加不同等级的荷载;同时对受力状态下的混凝土梁进行模拟海水干湿循环的侵蚀。通过试验,研究不同等级荷载和氯盐侵蚀耦合作用下混凝土梁抗氯盐侵蚀性能的变化规律。试验结果表明:(1)通过在梁的受压、受拉侵蚀面浇筑水池,以取水注水的方式来模拟干湿循环可以有效防止盐水对持荷装置的侵蚀,可使试验梁受力更稳定;(2)以施加荷载的大小占极限荷载的比例记做荷载水平λ。当λ=0.3时,受拉区混凝土开裂,各条裂缝最大宽度为0.04 mm,此时裂缝处氯离子浓度与不受力无裂缝混凝土内部氯离子浓度相近;当裂缝最大宽度为0.08 mm时,同深度处氯离子浓度较小幅度增加,影响氯离子传输速率的临界荷载裂缝宽度为0.04 mm。随着λ的增加,受拉区各位置氯离子浓度呈非线性增大,且距离裂缝越近,同深度处氯离子浓度越大;(3)λ<0.45时,混凝土梁受压区氯离子浓度随着荷载水平的增大而减小,当λ>0.45时,受压区氯离子浓度随着荷载水平的增大而增大;在压应力作用下,影响氯离子传输速率的临界λ=0.45。研究表明,荷载和氯盐侵蚀耦合作用对钢筋混凝土结构耐久性能具有巨大的危害,尤其是荷载裂缝处的氯盐侵蚀,实际工程中应采取相关措施加以防范。Coastal concrete structures have long been under the coupling action of sustained load and erosion environment.A loading device with sustained tension/compression stresses was designed,and 13 concrete beams were subjected to different levels of loads.At the same time,the concrete beams subjected to stress were eroded by simulated dry-wet cycles of seawater.Through experiments,the variation of chloride corrosion resistance of concrete beams under the coupling action of different grades of loads and chloride erosion is studied.The test results show that(1)by pouring a pool on the eroded surface of the beam under compression and tension,simulating the dry-wet cycle with water intake and injection can effectively prevent the erosion of salt water on the load-bearing device,and make the stress of the test beam more stable.(2)the load level is recorded in the proportion of the magnitude of applied load to the ultimate load.Whenλ=0.3,the concrete in tension zone cracks,and the maximum width of each crack is 0.04 mm.At this time,the chloride ion concentration in cracks is similar to that in non-stress cracked concrete.When the maximum width of cracks is 0.08 mm,the chloride ion concentration at the same depth increases slightly,which affects the critical load cracking of chloride ion transport rate.The width of the seam is 0.04 mm.With the increase ofλ,the chloride ion concentration in the tension zone increases nonlinearly,and the closer to the crack,the higher the chloride ion concentration at the same depth.(3)Whenλ<0.45,the chloride ion concentration in the compression zone of concrete beams decreases with the increase of load level,and whenλ>0.45,the chloride ion concentration in the compression zone increases with the increase of load level.The critical value of influencing chloride ion transport rate under compressive stress is 0.45.The research shows that the coupling effect of load and chloride erosion has great harm to the durability of reinforced concrete structures,especially chloride erosion at load crac

关 键 词：混凝土 干湿循环 持续荷载 裂缝 抗氯盐侵蚀性能 

分 类 号：TU528.01[建筑科学—建筑技术科学]