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锈蚀钢筋混凝土梁失效模式试验研究
Experimental Research on the Failure Mode of Corroded Reinforced Concrete Beams
【作者】 王飞;
【导师】 赵卓;
【作者基本信息】 郑州大学 , 建筑与土木工程(专业学位), 2014, 硕士
【摘要】 钢筋锈蚀是导致钢筋混凝土结构耐久性问题的最重要因素之一。混凝土结构中钢筋的锈蚀将导致钢筋保护层的开裂剥落、混凝土的损伤、钢筋有效截面面积的减小,并进而影响到结构的安全性和可靠性。本文针对钢筋混凝土受弯构件,基于钢筋锈蚀可能导致构件的失效,开展相关试验研究工作。主要研究工作内容如下:(1)基于目前相关研究中所存在的不足,拟定整体试验方案。主要包括钢筋的加速锈蚀、钢筋混凝土梁的荷载试验及破型试验等的方案设计。(2)通过钢筋加速锈蚀试验及构件破型,观测锈蚀过程及试验结果,分析钢筋的锈蚀程度与电阻率、通电时间、钢筋表面面积及保护层厚度之间的关系。试验结果表明:钢筋的锈蚀率主要受通电时间、钢筋表面积、保护层厚度及外包材料电导性等的影响,且钢筋的锈蚀呈现明显的不均匀性。(3)基于钢筋的锈蚀,通过对不同锈蚀程度的简支梁进行破坏荷载试验,分析试验梁承载能力、失效模式及变形性能等与钢筋锈蚀率之间的变化关系。试验结果表明:试验构件随钢筋锈蚀率的增加,其承载能力逐步降低。试验构件由适筋弯曲破坏逐渐变成类似少筋弯曲破坏。试验构件的刚度先增大后减小,且其屈服阶段逐渐趋于不明显。(4)研究分析了钢筋锈胀所导致的构件腐蚀损伤与受弯构件受力性能之间的关系。分析表明:当钢筋锈蚀率较高时,由钢筋锈胀导致的构件腐蚀损伤,对构件受力性能的影响趋于显著。
【Abstract】 Reinforcement corrosion is one of the most important factors leading to the issueof durability of reinforced concrete structures. Corrosion of reinforcement in concretestructures will cause the cracking and spalling of the protective layer, the damage ofconcrete, and the diminution of effective cross-sectional area of the reinforcement,thus to affect the safety and reliability of the structure. This paper forces on theflexural members of reinforced concrete, bases on the possible failures of thereinforcement corrosion, carries out research work related tests. The main contentsare as follows:(1) This paper bases on the current research related deficiencies, formulates theoverall test plan. It mainly includes scheme designs of the acceleration ofreinforcement corrosion, the load test of reinforced concrete beam and the brokentype test.(2) Through the of reinforced accelerated corrosion and the member broken typetest, observes the corrosion process and the test result, analyzes the relationshipbetween the corrosion degree of the reinforcement and resistivity, energizing time,surface area of reinforcement, protective layer thickness. The experimental resultsshow that the steel corrosion rate is mainly affected by energizing time, surface areaof reinforcement, and the influence of the protective layer thickness and theconductivity of covered materials, and corrosion of reinforcement appears to beuneven.(3) Bases on the reinforcement corrosion, through breaking load test of thesimply supported beam with different corrosion degrees, this paper analyze thechanging relationship between reinforcement corrosion rate and bearing capacity ofthe test beam, the failure modes and deformation properties. Experiment results showthat: with the increase of steel corrosion rate, the carrying capacity of component willgradually reduce. The damage of reinforcement bending will gradually becomesimilar less steel bending failure. Test component stiffness will increase then decrease and its yield stage will gradually tend to be not obvious.(4) The research analyzes the relationship between the component corrosiondamage caused by reinforcement rust up, and the flexural member force performance.Analysis shows that when the steel corrosion rate is higher, the component corrosiondamage caused by reinforcement rust up, the effects on mechanical properties ofcomponents tends to be more obvious.
【Key words】 flexural members of concrete; reinforcement corrosion; unevencorrosion; failure modes; mechanical property;