三轴应力下再生粗骨料塑性混凝土的力学性能和破坏准则

Mechanical Properties and Failure Criteria of Recycled Plastic Concrete under Triaxial Stresses

通过单轴、侧压相等和侧压不等三轴压缩试验,研究了再生粗骨料塑性混凝土(RPC)的应力-应变-强度特征,与原生粗骨料塑性混凝土(PC)性能进行了对比,并建立了基于空间八面体的强度破坏准则.结果表明:再生粗骨料塑性混凝土强度与围压的关系符合库伦破坏准则,其黏聚力低于原生粗骨料塑性混凝土,内摩擦角相差不大;再生粗骨料塑性混凝土应力-应变曲线由单轴下应变软化转变为三轴下塑化,且侧压越大,理想塑化越明显;在3种试验下,试件均出现了最大体应变,且随着侧压的增加而增大;再生塑性混凝土抗裂性能高于原生粗骨料塑性混凝土,且随侧压增大而增强.

Compared with plastic concrete(PC), behavior of stress-strain-strength of recycled plastic concretes(RPC) was studied by uniaxial, conventional triaxial and true triaxial compression tests. The strength failure criterion based on spatial octahedron stress was established. The results show that the Coulomb failure criteria is applicable for recycled plastic concretes, while the cohesion is less than that of plastic concretes, the internal friction is similar. Failure modes change from strain softening under uniaxial stresses to strain plasticizing under triaxial stresses, and it is more ideally plasticizing with the more lateral pressures. The maximum volumetric strain occurs in the three kinds of tests, and it becomes higher with the lateral pressure. The crack resistance of recycled plastic concrete is higher than that of plastic concretes, and increases with lateral pressures.