三向受压状态下再生混凝土的变形性能及损伤分析

Deformation and damage analysis of recycled concrete under tri-axial compression

为了研究再生混凝土在多应力状态下的变形行为,设计68个圆柱体试件对再生混凝土的取代率、侧向压力、混凝土的龄期,混凝土的强度进行了三向受力试验。试验给出了试件破坏全过程的应力-应变曲线,并深入分析了三轴受压再生混凝土的初始弹性模量、峰值应变、位移延性、能量耗散、损伤演变等性能参数。研究结果表明:龄期、侧向压力越大以及混凝土强度越高,再生混凝土的弹性模量越大;侧向压力可有效提高再生混凝土的变形性能;取代率对延性性能有一定的影响,但对耗能能力影响不大;龄期越大,再生混凝土强度越低,再生骨料服役年限越短,其延性性能和耗能性能越好;侧向压力越大,损伤曲线斜率越小,表明再生混凝土的损伤时间推迟,再生混凝土的损伤受取代率的影响不大。

In this paper, the mechanical performance of 68 recycled coarse aggregate concrete specimens subjected to multiaxial compression is studied. The replacement ratio of recycled coarse aggregate, the lateral confinement, the age of concrete, the recycled coarse aggregate sources and the concrete strength on tri-axial compression properties are investigated. The stress-strain curves of the specimens are obtained, then the ductility, the energy dissipation, the work and damage evolution of recycled concrete under tri-axial compression are analyzed deeply. The results show that, the higher the concrete age, the concrete strength and the lateral confinement, the greater the elastic modulus of recycled concrete;lateral confinement can effectively improve the bearing capacity and deformation performance of recycled concrete, replacement ratio of recycled concrete has a certain impact on the ductility performance, but influence on energy dissipation little; under the condition of the larger age of concrete, the smaller concrete strength as well as the service life of recycled aggregates, its ductility performance and energy dissipation performance become better; with the increasing of lateral confinement, the slope curves become smaller, and the damage of recycled concrete appears later, replacement ratio of recycled concrete has a little influence on damage evolution.