Mechanical Properties of Hybrid Fiber Recycled Concrete under Cyclic Compression

In this paper, the mechanical properties of 84 different hybrid fiber recycled aggregate concrete under cyclic compression are designed and studied. The modification effect of four kinds of hybrid fiber combinations of steel fiber (SF) and carbon fiber (CF), glass fiber (GF), polyvinyl alcohol fiber (PVA) and polypropylene fiber (PF) on recycled aggregate concrete (RAC) is analyzed from macro and micro point of view. The fracture interfacial inclination angle model considering fiber content was proposed, and the strengthening mechanism of fibers under cyclic loading was discussed The results show that the addition of fiber changes the failure mode of recycled aggregate concrete, SF has a great influence on the main fracture inclination angle of the specimen, while the fracture mode of carbon fiber makes it have a good crack resistance effect, and the combination of SF/CF can significantly increase the peak stress of RAC. SF/PVA combination has remarkable toughening effect and plastic strain inhibition effect. The stress degradation process model of hybrid fiber recycled aggregate concrete was proposed. Finally, according to the experimental results, the uniaxial cyclic compressive stress-strain constitutive equation of hybrid fiber concrete considering the fiber characteristic index was established.