钢管约束再生混凝土轴压试验研究

Experimental study on recycled concrete confined by steel tube under axial compression

以再生粗骨料取代率为试验主要研究参数,完成了15个钢管约束再生混凝土圆柱试件的轴压试验,分析了试件的受压破坏特性、轴向荷载-轴向应变关系以及约束再生混凝土的横向变形系数变化规律。试验和分析结果表明:钢管约束再生混凝土主要破坏形态为试件中部鼓曲,核心再生混凝土发生斜剪破坏;钢管约束再生混凝土与约束普通混凝土的受力过程基本相同,分为弹性和塑性发展阶段;钢管约束使核心再生混凝土强度得到明显提高,变形性能得到改善;再生粗骨料取代率变化对钢管约束再生混凝土的横向变形系数影响不大;钢管再生混凝土轴压极限荷载随着再生粗骨料取代率的增加而降低。最后根据试验数据拟合了钢管约束再生混凝土应力-应变关系表达式。

Based on the tests of 15 recycled concrete specimens confined by steel tube with different recycled coarse aggregate replacement percentages under axial compression,this paper investigates the failure feature,axial force-longitudinal deformation relationship and variation rule of lateral deformation ratio of the test specimens.It is found that the bulge in the middle of the specimen is the main failure phenomenon.The core concrete shows diagonal shearing failure.Similar to the normal concrete filled steel tube,the bearing process of recycled concrete confined by steel tube shows two stages： elastic stage and plastic stage.The strength and deformation capacity of core concrete is much higher than those under unconfined condition.The variation of recycled aggregate replacement percentage of the test specimen does not affect the lateral deformation ratio.The compressive strength of the test specimens decreases with the increase of recycled aggregate replacement percentage.Finally,the stress-strain relationship of the recycled concrete confined by steel tube is proposed based on the test data.