圆钢管再生陶瓷粗骨料混凝土短柱轴压试验研究

Experimental study on axial compression of circular concrete-filled steel tubular short columns with recycled ceramic coarse aggregate

为了有效利用废弃陶瓷,开展了受钢管约束的再生陶瓷粗骨料混凝土受力性能的研究,进行了18个圆钢管再生陶瓷粗骨料混凝土短柱的轴压试验,得到其破坏模态、承载力和荷载-纵向应变关系曲线等试验结果,并分析了截面含钢率、约束效应系数和再生陶瓷粗骨料取代率对短柱轴压性能的影响。试验和分析结果表明:圆钢管再生陶瓷混凝土轴压短柱的破坏模态受截面含钢率和约束效应系数影响,分为剪切破坏、腰鼓破坏和混合破坏;钢管对再生陶瓷混凝土的约束效果好于普通混凝土,取代率为100%的短柱与钢管普通混凝土短柱相比具有更高的承载力提高系数、混凝土强度提高系数和残余承载力比,以及更好的延性。将承载力实测值与各国现行规范中钢管混凝土承载力公式计算结果对比发现,现行规范对圆钢管再生陶瓷混凝土轴压短柱承载力的预测均过于安全,结合试验数据推导出适用于圆钢管再生陶瓷混凝土短柱的承载力简化计算公式,预测结果与试验结果拟合良好。

To make effective use of waste ceramics and investigate the mechanical properties of recycled ceramic coarse aggregate concrete(RCCAC)restrained by steel tube,the axial compression tests of 18 recycled ceramic coarse aggregate concrete-filled circular steel tubular(RCCACFST)short columns were carried out.The failure mode,bearing capacity and load-longitudinal strain curves were obtained.The effects of steel content,constraint effect coefficient and replacement rate of recycled ceramic coarse aggregate on axial compression properties of specimens were studied.The test and analysis results show that the failure modes of RCCACFST axial compression short columns are classified into shear failure,waist failure and mixed failure,which are affected by the steel content and constraint effect coefficient.The restraint effect of steel tube on RCCAC is better than that of control concrete.Compared with control concrete-flled steel tube,specimens with 100%replacement rate have higher improvement coefficient of bearing capacity,improvement coefficient of concrete strength,residual bearing capacity ratio and better ductility.By comparing the measured values of the test bearing capacity with the calculation results of the bearing capacity formulas for concrete-filled steel tube in the current codes of various countries,it is found that the predicted results of current codes are too conservative for the bearing capacity of the RCCACFST short axial compression columns.Combined with the test data,a simplified calculation formula for the bearing capacity of the RCCACFST short axial compression columns is derived,the predicted results agree well with the experimental results.