荷载与氯盐作用下再生混凝土大偏压柱受力性能

Mechanical performance of large eccentric compressive RAC columns under load and chloride

为研究再生混凝土柱在荷载与氯盐环境耦合作用下的受力性能,以再生骨料取代率、持荷大小、钢筋锈蚀率为变量,设计了10个钢筋再生混凝土大偏压柱构件,经过持续荷载作用状态下的通电锈蚀过程后进行承载力试验,以研究构件刚度、承载力、延性等特征,并取出钢筋测定实际锈蚀率。结果表明,随着再生骨料取代率、持荷的增大,构件锈胀裂缝数量增加、纵筋实际锈蚀率增大;构件刚度、承载力及延性均随再生骨料取代率增大而降低,但随持荷大小的变化规律各有不同;随着锈蚀率的增大,构件锈胀裂缝开展程度明显增加,构件刚度及承载力降低;锈蚀率超过3%时,构件延性随锈蚀率增大而降低,但当锈蚀率小于等于3%时,构件延性与未锈蚀构件相当。混凝土截面应变分布满足平截面假定,承载力试验结果与锈蚀钢筋混凝土柱承载力计算模型符合情况良好。研究结果可为再生混凝土柱在海洋环境中的应用提供参考。

To study the mechanical performance of recycled aggregate concrete（RAC） columns under sustained loads and chloride corrosion, we design ten sample columns of large eccentric compressive reinforced RAC and test them using three variables： replacement rate of recycled aggregate, loading strength, and corrosion rate of steel. In the experiment, the columns are electrically corroded under sustained load, and then their bearing capacity and corrosion rate of reinforcement steel bars are measured. And stiffness and ductility are also examined. The results show that the number of rust expansion cracks and the corrosion rate of longitudinal reinforcement both increase with the increase in replacement rate or loading strength. With an increase in replacement rate, stiffness, bearing capacity and ductility decrease, but the varying trends in loading strength are different. A higher corrosion rate results in significantly larger opening of rust expansion cracks and lower stiffness and bearing capacity. When corrosion rate increases, ductility decreases at the corrosion rate greater than 3% while it remains nearly the same at the rate lower than 3% as in the no corrosion cases. The strain distribution over a column section satisfies the plane section assumption. Our measurements of bearing capacity agree well with the calculations obtained using an analytical formula for bearing capacity of corroded reinforced concrete columns.