钢筋锈蚀率对预应力混凝土构件性能影响的试验研究

Experimental Study on Impact of Reinforcement Corrosion Rate onPerformance of Prestressed Concrete Components

预应力混凝土桥梁的耐久性往往由于内部普通钢筋锈蚀而劣化,依托东海大桥5×50m简支变连续箱梁项目,设计4根缩尺模型梁,在待锈蚀钢筋中埋设光纤传感器。将混凝土强度、保护层厚度、应力状态与原结构保持一致,控制变量为0,5%,10%,15%的钢筋锈蚀率。采用全浸入法对普通钢筋进行通电加速锈蚀,然后进行加载试验。结果表明,当锈蚀率不大于15%时,钢筋锈蚀不会显著降低预应力构件的抗弯承载力,锈蚀预应力构件仍为延性破坏模式,锈蚀造成开裂荷载和前期刚度明显下降,锈蚀钢筋与混凝土黏结性能破坏严重。

The durability of prestressed concrete bridges often deteriorates due to internal reinforcement corrosion.Four scaled model beams were designed and based on the 5×50m simple-supported continuous box girder of the Donghai Bridge.Fiber optic sensors were embedded in corroded reinforcement.The concrete strength,protective layer thickness,and stress state were consistent with the original structure and the controlled variables are reinforcement corrosion rates,that is 0,5%,10%,and 15%.The full immersion method was used to accelerate corrosion of the ordinary reinforcement,followed by a loading test.The results showed that when the corrosion rate was no more than 15%,the reinforcement corrosion did not significantly reduce the bending bearing capacity of the prestressed components.The bending failure mode of the corroded prestressed components remained ductile failure,with the corrosion causing a significant decrease in cracking load and early stiffness,the bond properties of corroded reinforcement and concrete was damaged.