约束再生混凝土足尺试件受压应力应变全曲线试验研究

为研究箍筋约束再生混凝土的单轴受压应力应变全曲线，对9个直径为500 mm、高度为1 500 mm的再生混凝土圆形柱进行试验，采用20 000 kN伺服液压试验机进行位移控制加载。试验参数主要为纵筋率、箍筋间距与直径、加载应变速率。试验结果表明，箍筋间距、配箍率对试件延性影响较大。当加载应变速率由0.000 003/s增大到0.003 3/s时，试件的峰值应力增大1.14倍。分析表明，再生混凝土应力应变全曲线与普通混凝土类似，但下降段较普通混凝土陡峭，脆性更为明显。

Experimental study on complete stress-strain curve of full-scale specimen of confined recycled concrete under compression

To study the complete stress-strain curve of stirrup confined recycled concrete under uniaxial loading, we tested on nine circular column specimens of recycled concrete which have a diameter of 500 mm and a height of 1 500 mm. In this test,we used a servo-hydraulic test machine with a capacity of 20 000 kN for displacement and loading control. The main test parameters are longitudinal reinforcement ratio, the spacing and diameter of stirrup, and applied strain rate. The results show that the spacing of stirrup and stirrup ratio have great influence on the ductility of specimens. The peak stress of specimen increases 114% when the applied strain rate increases from 0.000003/s to 0.0033/s. The complete stress-strain curve of recycled concrete is similar to that of normal concrete but the descending branch is stiffer than that of normal concrete, which means that the recycled concrete is more brittle than normal concrete.