钢筋再生混凝土梁高温后受弯承载力试验及计算

为研究高温后钢筋再生混凝土梁的受弯性能,以温度、再生粗骨料取代率、混凝土强度为变化参数,设计了17个试件进行高温后的静力加载试验,观察了高温后试件的受力破坏过程,绘制出荷载-挠度、截面应变分布曲线,分析了各变化参数对高温后钢筋再生混凝土梁受弯性能的影响规律,并探讨了其抗弯承载力和挠度计算方法。研究结果表明:钢筋再生混凝土梁在历经高温后的受弯破坏形态基本与常温下相同;随着温度的升高,试件的剩余承载力先增大后减小,刚度逐渐降低,损伤退化速度变快,延性降低,耗能能力和峰值挠度减小;随着再生粗骨料取代率的增加,试件加快进入损失残余阶段,耗能能力和峰值挠度增大;混凝土强度等级的提高,能有效提高高温后再生混凝土梁的承载力和增大峰值挠度。

Flexural behavior test and bearing capacity calculation of reinforced recycled concrete beam after exposed high temperatures

In order to study the flexural behavior of reinforced recycled concrete beams after experiencing high temperature, seventeen specimens, involving three varying parameters such as temperature, recycled coarse aggregate replacement ratio and concrete strength, were designed for monotonic static loading test after experiencing high temperature. Based on the tests, the mechanical failure pattern of specimens after exposed high temperature was observed, so that those important information including load-deflection curves and cross-sectional stress distribution can be obtained. Furthermore, the effects of these varying parameters on the flexural behavior of reinforced recycled concrete beams after experiencing high temperature were analyzed, and the calculation method of the bending bearing capacity and deflection of reinforced recycled concrete beams was also discussed. The results show that the failure mode of reinforced recycled concrete beam after high temperature is similar to that at the normal temperature. Additionally, due to the high temperature, the residual bearing capacity of the specimen showed a trend of decrease after the first increase, stiffness decreases, damage degradation speed become faster, ductility, energy dissipation and peak deflection decreases. With an increased replacement ratio, the faster the specimen enters the residual phase of the loss, the energy dissipation capacity and the peak deflection increase. It also indicates that the improvement of concrete strength level can effectively improve the bearing capacity of the regenerated concrete beam and increase the peak deflection after high temperature.