废弃纤维再生混凝土单轴受压力学性能试验研究

Experimental study on uniaxial compression properties of waste fiber recycled concrete

将废弃纤维及再生骨料掺入混凝土中制备废弃纤维再生混凝土,测定废弃纤维再生混凝土应力-应变全曲线及弹性模量,分析了不同废弃纤维含量、废纤维长度再生骨料替代率及水灰比对峰值应力、峰值应变、弹性模量的影响,通过拟合得到废弃纤维再生混凝土本构方程。对废弃纤维再生混凝土受压到破坏的全过程进行分析,拟合得到废弃纤维再生混凝土损伤模型。结果表明,随着纤维体积含量的增大峰值应力逐渐增大;随着纤维长度增长峰值应力先增大后减小;再生骨料替代率大于50%后对混凝土强度影响较大;峰值应力随着混凝土水灰比的增加逐渐减小;随着水灰比、废弃纤维长度、废弃纤维含量和再生骨料替代率的增加,峰值应变逐渐增大;废弃纤维对弹性模量有提高作用;随着再生骨料替代率及水灰比的增大,弹性模量逐渐降低。将废弃纤维再生混凝土的应力-应变曲线数据进行拟合,建立废弃纤维再生混凝土受压本构方程。随着废弃纤维长度增长、再生骨料替代率的增加和水灰比的增大,损伤变量增长速度逐渐变大;而随着废弃纤维体积掺量的增多,损伤变量增加速度的逐渐变缓。通过拟合得到了废弃纤维再生混凝土单轴受压损伤模型,试验数据与拟合结果吻合良好。

The preparation of waste fiber recycled concrete by mixing waste fiber and recycled aggregate into concrete were introduced.The stress-strain curve and elastic modulus of waste fiber recycled concrete are measured,and the effects of different waste fiber content,waste fiber length,recycled aggregate replacement rate,and water cement ratio on peak stress,peak strain,and elastic modulus were analyzed.The constitutive equation of waste fiber recycled concrete was obtained through fitting.Analyze the entire process from compression to failure of waste fiber reinforced recycled concrete,and fit the damage model of waste fiber reinforced recycled concrete.The results indicate that the peak stress gradually increases with the increase of fiber volume content;As the fiber length increases,the peak stress first increases and then decreases;When the replacement rate of recycled aggregate exceeds 50%,it has a significant impact on the strength of concrete;The peak stress gradually decreases with the increase of concrete water cement ratio;With the increase of water cement ratio,waste fiber length,waste fiber content,and recycled aggregate substitution rate,the peak strain gradually increases;Waste fibers have an increasing effect on the elastic modulus;As the replacement rate of recycled aggregate and the water cement ratio increase,the elastic modulus gradually decreases.Fit the stress-strain curve data of waste fiber recycled concrete and establish the compressive constitutive equation of waste fiber recycled concrete.As the length of waste fibers increases,the replacement rate of recycled aggregates increases,and the water cement ratio increases,the growth rate of damage variables gradually increases;As the volume fraction of waste fibers increases,the rate of increase in damage variables gradually slows down.A uniaxial compression damage model of waste fiber recycled concrete was obtained through fitting,and the experimental data is in good agreement with the fitting results.