疲劳荷载对橡胶-钢纤维混凝土变形、能量及损伤性能的影响

Effect of Fatigue Load on Deformation,Energy and Damage Properties of Rubber-steel Fiber Concrete

为了探究橡胶-钢纤维混凝土(rubber-steel fiber concrete,R-SFC)在疲劳荷载下的变形、能量以及损伤特性,利用电液伺服万能试验机对R-SFC进行静态压缩增幅循环加-卸载试验。结果表明:应力-应变曲线由密变疏,同时应力退化也逐渐增大;随着循环次数的增加,不闭合度呈现先减小后趋于稳定再增大的“三阶段”变化;加、卸载变形模量随着循环次数的增加而逐渐增大,且卸载变形模量大于相应的加载变形模量;加载应变、累积残余应变随着循环次数的增加而增大,且钢纤维混凝土(steel fiber reinforced concrete,SFC)的加载应变和累积残余应变均大于R-SFC;总输入能速率、弹性应变能速率随着循环次数的增加而增大;随着循环次数的增加,耗散能先缓慢增大再迅速增大,且R-SFC的耗散能大于SFC;累积残余应变损伤和能量耗散损伤随着循环次数的增加而逐渐增大,且R-SFC的能量耗散损伤大于SFC,但R-SFC的累积残余应变损伤则小于SFC。

To explore the deformation,energy and damage characteristics of rubber-steel fiber concrete(R-SFC)under fatigue load,a amplification cyclic loading-unloading test of R-SFC under static compression was carried out using an electro-hydraulic servo universal testing machine.The results show that the stress-strain curves change from dense to sparse,and the stress degradation also increases graduall.With the increase of the number of cycles,the unclosed degree shows a“three-stage”change that first decreases,then tends to be stable and then increases.The loading and unloading deformation modulus increase gradually with the increase of the number of cycles,and the unloading deformation modulus is greater than the corresponding loading deformation modulus.The loading strain and cumulative residual strain increase with the increase of the number of cycles,and the loading strain and cumulative residual strain of steel fiber reinforced concrete(SFC)are larger than those of R-SFC.The total input energy rate and elastic strain energy rate increase with the increase of the number of cycles.With the increase of the number of cycles,the dissipative energy first increases slowly and then increases rapidly,and the dissipative energy of R-SFC is larger than that of SFC.The cumulative residual strain damage and energy dissipation damage increase gradually with the increase of the number of cycles,and the energy dissipation damage of R-SFC is larger than that of SFC,but the cumulative residual strain damage of R-SFC is smaller than that of SFC.