多组合混杂纤维改性再生混凝土循环受压性能试验

Effect of multi-composite hybrid fiber on cyclic compression performance of recycled concrete

  • 摘要: 为研究多组合混杂纤维对再生混凝土(HFRAC)循环受压性能的影响规律,对84个试件进行单调受压试验和单调循环受压试验,分析了钢-碳纤维(SF-CF)、钢-玻璃纤维(SF-GF)、钢-聚丙烯纤维(SF-PF)和钢-聚乙烯醇纤维(SF-PVA) 4种纤维组合和纤维体积掺量对循环受压性能的影响。结果表明:与普通再生混凝土相比,HFRAC的破坏形态为延性破坏;各组HFRAC试件在循环受压下的应力-应变曲线包络线与单调受压应力-应变曲线近似一致;与钢纤维再生混凝土相比,SF-GF混杂纤维和SF-PVA混杂纤维对塑性应变累积的抑制效果更好;掺入弹性模量较大的SF-CF混杂纤维对再生混凝土刚度退化率的增加和滞回耗能能力提高有显著作用,掺入1.0vol%SF+0.5vol%CF时再生混凝土的刚度退化率增加了43.4%。最后,在试验结果的基础上,建立了HFRAC单轴循环受压应力-应变关系全曲线方程,计算结果与试验结果吻合良好。

     

    Abstract: In order to study the effect of multi-composite hybrid fiber on the cyclic compression behavior of recycled concrete (HFRAC), monotone compression tests and monotone cyclic compression tests were carried out on 84 specimens. The effects of steel-carbon fiber (SF-CF), steel-glass fiber (SF-GF), steel-polypropylene fiber (SF-PF) and steel-polyvinyl alcohol fiber (SF-PVA) on the cyclic compression properties were analyzed. The results show that compared with ordinary recycled concrete, the failure mode of HFRAC is ductile failure, the envelope of stress-strain curve of HFRAC specimens under cyclic compression is approximately consistent with the stress-strain curve under monotonic compression, and the inhibition effect of SF-GF hybrid fiber and SF-PVA hybrid fiber on plastic strain accumulation is better than that of steel fiber recycled concrete. The addition of SF-CF hybrid fiber with large elastic modulus plays a significant role in increasing the stiffness degradation rate and hysteretic energy dissipation capacity of recycled concrete, and the stiffness degradation rate of recycled concrete increases by 43.4% when 1.0vol%SF+0.5vol%CF was added. Finally, on the basis of the experimental results, the full curve equation of stress-strain relationship of HFRAC under uniaxial cyclic compression is established, and the calculated results are in good agreement with the experimental results.

     

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