锈损不锈钢钢筋混凝土梁受弯性能退化试验研究  

Experimental study on degradation of flexural performance of corroded stainless steel bars reinforced concrete beam

作　　者：孙晓燕[1] 王海龙[1] 于凤荣 SUN Xiaoyan;WANG Hailong;YU Fengrong(College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]浙江大学建筑工程学院,浙江杭州310058

出　　处：《建筑结构学报》2021年第6期160-168,共9页Journal of Building Structures

基　　金：国家自然科学基金项目(51579220);国家863计划(2015AA03A502)。

摘　　要：为了得到海洋环境下不锈钢钢筋混凝土梁的服役性能演变规律,给结构性能评价和使用寿命评估提供可靠数据,采用加速锈蚀试验方法获取了不同锈蚀状态的不锈钢钢筋混凝土梁,开展了受弯性能试验研究,测试了纵筋的质量锈蚀率、主裂缝区域的纵筋锈蚀率和锈胀裂缝宽度,探讨了锈蚀对受弯梁破坏模式、裂缝开展和承载力的影响规律,并对不锈钢钢筋与普通钢筋混凝土梁的锈蚀特征与承载力的差异性及其主要原因加以分析。结果表明:相比普通碳素钢,不锈钢钢筋锈后形态更倾向于坑蚀,因而在相同的质量锈蚀率下,不锈钢钢筋混凝土梁承载力退化更为严重;不锈钢中铁元素含量较低,在相同的锈蚀时间下不锈钢锈蚀产物膨胀率较小,使得不锈钢钢筋混凝土构件的锈胀裂缝发展较为缓慢;由于锈胀裂缝的存在,受拉混凝土极易大块剥落,裂缝发展迅速;影响不锈钢钢筋混凝土梁受弯承载力的最主要因素是主裂缝附近区域内的不锈钢钢筋局部锈蚀率。不考虑不锈钢钢筋的非线性强化,基于锈蚀钢筋名义强度和平截面假定得到了不锈钢钢筋混凝土梁受弯承载能力计算模型,采用该模型得到的计算值与试验结果吻合较好,模型可以很好地反映锈损梁的受弯性能退化规律。To clarify the evolution of service performance of stainless steel reinforced concrete structure in marine environment and provide scientific reference for performance evaluation and life prediction, an accelerated corrosion method was adopted in this study to obtain various corroded stainless steel reinforced concrete beams, and then mechanical test was carried out to figure out the flexural behaviors of these corroded beams. The mass loss of stainless steel, the local corrosion degree of steel bars in the area near the main crack, and the width of corrosion-induced crack were measured. Furtherly, the effects of steel corrosion on the failure mode, development of cracks and bearing capacity were analyzed. Moreover, the causes leading to the corrosion and mechanical differences between stainless and carbon steel reinforced concrete beams were clarified. The results show that stainless steel is vulnerable to pit corrosion as compared to ordinary carbon steel, as a result, the degradation of bearing capacity of stainless steel reinforced concrete beam is more serious than that of carbon steel reinforced concrete beam with the same mass loss. The development of corrosion-induced crack in stainless steel reinforced concrete members is slower due to the lower content of iron in stainless steel and its lower expansion rate of corrosion product. Because of the corrosion-induced cracks, the concrete in tension zone is easy to peel off, and the cracks develop more rapidly under flexural load. The main factor affecting the flexural capacity of stainless steel reinforced concrete beams is the local corrosion degree of steel bars in the area near the main crack. The calculation model of flexural capacity of stainless steel reinforced concrete beams was obtained based on the plane section assumption and the nominal strength of corroded stainless steel bars without considering its nonlinear hardening contribution. The calculated values are in good agreement with the experimental results, indicating that the proposed model can

关 键 词：混凝土梁 不锈钢钢筋 锈蚀率 锈胀裂缝 静力试验 受弯性能 

分 类 号：TU528[建筑科学—建筑技术科学] TU317.1