钢-PVA混杂纤维高强再生骨料混凝土断裂性能

Fracture behaviors of hybrid steel-PVA fiber reinforced high strength recycled aggregate concrete

为提高再生骨料混凝土的断裂性能,通过三点弯曲梁断裂试验,研究钢纤维、钢-PVA混杂纤维对高强再生骨料混凝土(RAC)断裂性能的影响。结果表明:未掺纤维的高强RAC脆性较大,断裂性能差,而钢纤维、钢-PVA混杂纤维对高强RAC的断裂破坏延缓作用明显;钢纤维与PVA纤维混杂后的高强RAC比单掺钢纤维时,其荷载-变形曲线更为饱满且下降段更为平缓;单掺钢纤维时高强RAC的失稳韧度及断裂能显著提升,但起裂韧度基本没有提高,而钢纤维与PVA纤维混杂后RAC各项断裂参数均有明显改善,对其起裂韧度的提升效果较好,在体积掺量为0.2%的PVA纤维与体积掺量为1.0%的钢纤维混杂时混杂效应较优,对高强RAC各项断裂性能的改善效果最为理想。

To improve the fracture behaviors of recycled aggregate concrete, the effect of steel fiber and hybrid steel-polyvinyl alcohol(steel-PVA) fiber on the fracture properties of high strength recycled aggregate concrete(RAC) was studied by three-point bending beam test. The results show that the high strength RAC without fiber has obvious brittle behavior and the fracture properties are poor. It is observed that the fracture failure of steel fiber reinforced high strength RAC and hybrid steel-PVA fiber reinforced high strength RAC is significantly delayed. Compared with the steel fiber reinforced high strength RAC, the load-deformation curves of the hybrid steel-PVA fiber reinforced high strength RAC are plumper, and each downward part of the curves is more gradual. The unstable fracture toughness and fracture energy of the steel fiber reinforced high strength RAC are increased significantly, but the crack initiation fracture toughness is limitedly improved. While the fracture behaviors of the hybrid steel-PVA fiber reinforced high strength RAC are improved obviously, especially the crack initiation toughness. When the 1.0% steel fiber is mixed with the 0.2% PVA fiber, a better hybrid effect is obtained, and the improvement effect on the fracture behaviors of high strength RAC is optimal.