钢筋连接区锈蚀后的抗拉性能及破坏形态试验研究

Experimental study on tensile properties and failure patterns of corroded steel bars joint region

为研究不同连接方式钢筋连接件在不同锈蚀程度下的抗拉性能和破坏形态,对双面电弧焊、套筒冷挤压和墩粗直螺纹3种连接方式的钢筋连接件进行电化学腐蚀试验,并对腐蚀后的钢筋连接件进行拉伸试验,分析锈蚀程度对不同连接方式钢筋连接件的抗拉性能和破坏形态的影响。试验结果表明,双面电弧焊钢筋连接件的抗腐蚀能力最强,在0.4A恒定电流下通电240h后平均抗拉强度降低约22%;墩粗直螺纹钢筋连接件的抗腐蚀能力最弱,相同腐蚀环境下其平均抗拉强度降低约达66%;与上述两种钢筋连接方式相比,套筒冷挤压钢筋连接件的抗腐蚀能力处于二者之间。腐蚀环境下钢筋连接件的拉伸破坏形态主要有钢筋拉断、连接区断裂及粘结-滑移破坏3类,与连接件的锈蚀程度和连接方式有关。

In order to study the tensile properties and failure patterns of the rebars with different connection modes under different corrosion degree,the electrochemical corrosion tests were carried out on steel connectors with three kinds of connection modes of double-sided arc welding,sleeve cold extrusion and coarse straight thread.Then,the tensile tests were conducted for these connectors to analyze the influence of corrosion degree to the tensile properties and failure patterns for them.The test results show that the corrosion resistance of the double-sided arc welding is the strongest,its average tensile strength is reduced by about 22%after 240 hours under 0.4A constant current;the corrosion resistance of the connecting parts of the coarse straight threaded rebar is the weakest,its average tensile strength is decreased by about 66%in the same corrosive environment.Compared with the above two kinds of reinforcing bars,the corrosion resistance of the connecting parts of the sleeve cold extruded steel is between them.Besides,it also can be found that the tensile failure modes of rebar joints subjected to corrosive environment mainly include the steel bar break,connection zone failure,and bond-slip fracture,which is related to the corrosion degree and connection modes of the connecting parts.