钢纤维的掺量和长径比对超高性能混凝土施工和力学性能的影响

Influence of Steel Fiber Content and Aspect Ratio on Construction and Mechanical Properties of Ultra-high Performance Concrete

摘要:

研究了不同钢纤维掺量（1.5%~2.5%）及长径比（65、80、90）对超高性能混凝土（ultra-high performance concrete，UHPC）施工性能、力学性能的影响。通过开展扩展度试验、流动度试验、抗压强度试验和哑铃型试件的直接拉伸试验，系统分析了钢纤维不同参数搭配，对混凝土的施工性能和力学指标的作用规律。研究结果表明：随着钢纤维掺量的增加和长径比的增大，UHPC的扩展度和流动性逐渐降低；在一定范围内（掺量2.0%以上），抗压强度和抗拉性能显著提高，并表现出应变硬化行为，极限抗拉应变达到3 000με以上。结果可为钢纤维增强UHPC的配比设计提供参考。

Abstract:

The influences of different steel fiber contents (1.5%~2.5%) and aspect ratios (65, 80 and 90) on the construction and and mechanical properties of ultrahigh performance concrete (UHPC) are studied. By conducting scalability tests, fluidity tests, compressive strength tests and direct tensile tests on dumbbell-shaped specimens, the effect laws of different parameter combinations of steel fibers on the construction performance and mechanical indicators of concrete are systematically analyzed. The research result shows that as the steel fiber content and aspect ratio increase, the scalability and fluidity of UHPC are gradually decreasing. Within a certain range (above a content of 2.0%), the compressive strength and tensile properties significantly improve, exhibiting strain-hardening behavior with the ultimate tensile strain reaching over 3 000με. The results can provide a reference for the proportion design of steel fiber-reinforced UHPC.