混杂纤维高强自密实混凝土弯曲韧性试验

Experiment on Flexural Toughness of High-strength Self-compacting Concrete with Hybrid Fiber

为探究混杂纤维改性混凝土的韧性作用机理,以镀铜微丝钢纤维和纳米碳纤维掺量为参数,制备了混杂纤维高强自密实混凝土,进行了弯曲韧性试验。基于试验数据,绘制荷载-挠度曲线,以弯曲韧度比为量化指标,采用数值分析方法对试件样本空间进行扩参数分析。结果表明:纳米碳纤维与镀铜微丝钢纤维在高强自密实混凝土开裂的不同阶段发挥不同层次的改性作用,使混凝土峰值荷载变形得以改善的同时,提高其极限荷载、初始弯曲韧度比和弯曲韧度比;初始弯曲韧度比最大提高幅度为34.5%,HS-S9C6试验组弯曲韧度比达0.84,且随挠度增长,弯曲韧度比下降速率较慢,混杂纤维较好地发挥了改性高强自密实混凝土的韧性作用。

In order to study the toughness function mechanism of concrete modified by hybrid fiber,the copper-coated microfilament steel fiber（SF）and carbon nanofiber（CNF）proportion were taken as parameters,and the high-strength self-compacting concrete with hybrid fiber was prepared to conduct flexural toughness experiment.Based on the experimental data,the loaddeflection curves were obtained.The flexural toughness ratio was applied as the quantitative index,and the numerical analysis method was applied to conduct parameter analysis on sample space of specimens.The results show that CNF and SF play modification effect of different levels at different crack stages of high-strength self-compacting concrete.The peak load deformation of concrete is improved,and the ultimate load,initial flexural toughness ratio and flexural toughness ratio are promoted.The initial flexural toughness ratio is increased by 34.5%,and the flexural toughness ratio of HS-S9C6 test group reaches 0.84.The descent rate of flexural toughness ratio is slower along with the increase of deflection.The hybrid fiber play a better role in improving the toughness of high-strength self-compacting concrete.