加增韧剂钢–聚丙烯纤维桥梁锚固混凝土的抗冲击性能

Study on Impact Resistance of Steel-Polypropylene Fiber Concrete with Toughening Agent

摘要: 桥梁伸缩缝锚固混凝土受冲击挤压荷载作用较大，应具有较高的力学强度和良好的抗变形韧性。为了提升锚固混凝土的抗冲击性能，论文研究自主开发了一种自由落锤式冲击试验仪，制备了C50 + 钢纤维 + 聚丙烯纤维 + 增韧剂的混杂纤维混凝土，并与普通混凝土、钢纤维混凝土和聚丙烯纤维混凝土三种混凝土作对比分析，试验测试了四种混凝土的抗冲击性能，研究了混杂纤维 + 增韧剂混凝土的技术性能。结果表明：与普通混凝土相比，当加入钢纤维后，初裂冲击耗能提升了5.2倍，终裂冲击耗能提升了5.3倍；当加入聚丙烯纤维后，初裂冲击耗能提升了4.7倍，终裂冲击耗能提升了4.4倍；当加入混杂纤维 + 增韧剂后，初裂冲击耗能提升了9.7倍，终裂冲击耗能提升了9.3倍；加入纤维和增韧剂后，混凝土在开裂后可吸收更多的冲击能量；在所设计的配合比条件下，钢纤维和聚丙烯纤维混杂作用时表现出良好的正混杂效应。

Abstract: Bridge expansion joint anchored concrete is subject to large impact extrusion load, so it should have high mechanical strength and good resistance to deformation toughness. In order to improve the impact resistance of anchorage concrete, a free drop hammer impact tester was independently developed in this research. We prepared hybrid fiber concrete of C50-steel fiber-polypropylene fiber-toughening agent, and compared it with ordinary concrete, steel fiber concrete, and polypropylene fiber concrete. The impact resistance of four kinds of concretes was tested, based on which the impact resistance of hybrid fiber-toughening agent concrete was further analyzed. The results show that compared with ordinary concrete, when steel fiber is added, the initial crack impact energy consumption increases by 5.2 times, and the final crack impact energy consumption increases by 5.3 times. When polypropylene fiber was added, the impact energy consumption of the initial crack was increased by 4.7 times, and the impact energy consumption of the final crack was increased by 4.4 times. When the hybrid fiber-toughening agent was added, the initial fracture impact energy consumption increased by 9.7 times, and the final fracture impact energy consumption increased by 9.3 times. It can be found that after adding fiber and toughening agents, concrete can absorb more impact energy between the initial crack and final crack. Under the condition of the designed mixing proportion, the mixture of hybrid fiber and the toughening agent has a positive hybrid effect on impact resistance.