钢筋锈蚀对混凝土梁抗弯性能影响试验

Study on Effect of the Corrosion of Reinforcement on Concrete Beam Bending

目的对在役钢筋混凝土结构进行耐久性评定和剩余寿命预测,为新建项目进行耐久性预评估和寿命设计提供参考.方法对12根钢筋混凝土梁进行快速锈蚀试验和梁的抗弯性能试验.同时对48根不同锈蚀率的钢筋进行拉伸试验,选用6根未锈蚀钢筋进行对比,研究锈蚀钢筋力学性能退化机理.结果钢筋混凝土梁跨中截面混凝土压应变随着锈蚀率的增加先减小后增大.锈蚀率为3.53%的梁的开裂荷载稍大于未锈蚀梁的开裂荷载,而锈蚀率为8.07%的梁的开裂荷载明显比锈蚀率3.53%的梁低.锈蚀钢筋应力应变曲线发生较大变化,屈服点不明显,其性能近似脆性材料,相关构件易发生无预兆的脆性破坏.结论锈蚀梁纯弯段内平均应变的分布形式仍符合平截面假定,推导出的锈蚀钢筋混凝土梁抗弯承载力计算公式可用于实际工程计算中.

This paper aims to put forward the durability assessment and remaining life prediction of in-service re- inforced concrete structure and provide the reference of durability evaluation and design. In order to study the cor- reded reinforced mechanical performance degradation mechanism,12 reinforced concrete beams have been used in laboratory accelerated corrosion test and beam bending resistance test. This paper also uses 48 different corrosion rate of steel in tensile test and chooses 6 not rust reinforcement as contrast specimen. The compressive strain of re- inforced concrete beam mid span cross section decreased first and then increased with the increase of corrosion rate. The cracking load of the beam which corrosion rate is 3.53% is slightly greater than not corroded beam＇s. And the crack load of the beam which corrosion rate is 8.07% is obviously lower than the beam which corrosion rate is 3.53%. Stress strain curve of corroded reinforced has great change,whose yield point is not obvious and approximate brittle material performance and related components are prone to brittle failure without warning. Based on the analysis of the test, we can conclude that distribution form of pure bending section of corrosion rein- forced concrete beam is still fit plane cross-section assumption. The deduced formula of flexural bearing capacity of corroded reinforced concrete beams can be used in actual engineering calculation.