海水冻融腐蚀耦合环境下钢筋混凝土梁疲劳试验研究

发布时间：2018-09-14 10:48

【摘要】：我国北方沿海地区公路桥梁受海水侵蚀和冻融作用明显,缩短了钢筋混凝土结构寿命。为研究这一问题,在分析这类地区工程地质环境的基础上,利用自研的冻融腐蚀培养装置和循环载荷装置开展了上限荷载0.15P~0.40P(P为试件极限荷载)、循环荷载5~30万次与冻融腐蚀相耦合条件下钢筋混凝土梁的疲劳试验,通过监测不同疲劳侵蚀龄期试件的挠度、应力应变和承载力值,揭示其疲劳劣化过程机理。研究结果表明:首先,海水环境中Cl~-含量高达19 000 mg/L,SO4~(2-)离子含量高达2 500 mg/L,对钢筋混凝土结构具有分解性和膨胀性腐蚀作用;其次,试件裂缝宽度与上限载荷、循环次数均成正相关关系,但循环荷载达到一定次数后不再扩展;最后,本文发现疲劳荷载小于0.25P时,试件性能基本不变,受冻融腐蚀后其相应荷载降低至0.20P,试验完成后其屈服荷载和极限荷载平均降低了约23.8%和10.5%,说明海水冻融腐蚀对钢筋混凝土构件劣化作用明显。
[Abstract]:Highway bridges in the northern coastal areas of China are obviously affected by seawater erosion and freezing and thawing, which shortens the life of reinforced concrete structures. In order to study this problem, on the basis of analyzing the engineering geological environment of this kind of area, The fatigue tests of reinforced concrete beams with upper limit load (P as the ultimate load) and cyclic load of 5 ~ 300000 times coupled with freeze-thaw corrosion were carried out by using self-developed freeze-thaw corrosion culture device and cyclic load device. The mechanism of fatigue deterioration was revealed by monitoring the deflection, stress strain and bearing capacity of specimens at different fatigue erosion ages. The results show that, firstly, the content of Cl~- in seawater environment is as high as 19 000 mg/L,SO4~ (2-) ion content, and the content of Cl~- is as high as 2 500 mg/L, which has the effect of decomposition and expansion corrosion on reinforced concrete structure, secondly, the crack width and upper limit load of the specimen are obtained. The number of cycles is positively correlated, but the cyclic load does not propagate after a certain number of times. Finally, it is found that when the fatigue load is less than 0.25 P, the performance of the specimen is basically unchanged. The corresponding load is reduced to 0.20Pafter freeze-thaw corrosion, and the yield load and ultimate load are reduced by about 23.8% and 10.5% respectively after the test is completed, which shows that the effect of seawater freeze-thaw corrosion on the deterioration of reinforced concrete members is obvious.
【作者单位】：辽宁铁道职业技术学院;云南大学建筑与规划学院;
【基金】：云南省交通厅科技项目(2013(c)07)
【分类号】：U446.1

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