混杂纤维层数对再生混凝土力学性能的影响研究

Effect of Hybrid Fiber Layer Number on Mechanical Properties of Recycled Concrete

为改善再生混凝土的强度和韧性,采用质量分数为12%的粉煤灰代替部分水泥,并以占总质量百分比为28%的再生粗骨料代替部分天然粗骨料配制的再生混凝土作为基准组,以此进行不同层数混掺纤维的再生混凝土试验。研究结果表明:增加混杂纤维的撒布层数能够提升再生混凝土的抗压强度,但提升的程度有限;当混杂纤维层数为2层时,能够使混凝土的劈裂抗拉强度显著增加;随着混杂纤维层数的不断增加,再生混凝土的拉压比表现出先增大后减小的变化趋势,弹强比则先减小后增大趋势;再生混凝土力学指标均处于良好状态的最佳纤维撒布层数为4层。

In order to improve the strength and toughness of recycled concrete,fly ash with a mass fraction of 12%was used to replace part of the cement,the recycled concrete was prepared with recycled coarse aggregate accounting for 28%of the total mass instead of some natural coarse aggregate as the reference group,and the recycled concrete with different layers of hybrid fiber was tested.The results show that increasing the layer number of hybrid fiber can improve the compressive strength of recycled concrete,but the degree of improvement is limited.When the number of hybrid fiber layers is 2,the splitting tensile strength of concrete can be significantly increased.With the increasing number of hybrid fiber layers,the tensilecompression ratio of recycled concrete increases first and then decreases,while the elastic-strength ratio decreases first and then increases.The optimum hybrid fiber layer number of recycled concrete is 4 layers when the mechanical indexes are in good condition.