掺秸秆灰、钢渣等再生骨料混凝土性能研究

Mechanical Properties of Recycled Aggregate Concrete Mixed with Straw Ash and Steel Slag

采用正交设计方法,以取代率为25%的再生骨料混凝土的抗压强度和劈裂强度为考核指标,分析了秸秆灰、石墨烯、玄武岩纤维和钢渣的掺量对再生骨料混凝土抗压强度和劈裂强度的影响,试验结果表明:钢渣D、石墨烯B、秸秆灰A对再生混凝土抗压强度的影响基本一致,在试验范围内,随着各掺量的增加,再生混凝土强度先增加后减小,各因素在二水平附近时为最佳掺量;随着玄武岩纤维C掺量的增加再生骨料混凝土抗压强度呈现逐渐增长的趋势。钢渣D、石墨烯B对早期的劈裂强度影响较大,随着各掺量的增加,再生混凝土劈裂强度先增加后减小;随着玄武岩纤维C掺量的增加再生骨料混凝土劈裂强度呈现逐渐增长的趋势。通过方差和极差分析综合考虑:在秸秆灰掺量为5%、石墨烯掺量为1.8%、玄武岩纤维掺量为0.3%、钢渣掺量为15%的情况下,对应再生混凝土7 d、28 d抗压强度指标相对较高(25.27 MPa、34.28 MPa)以及7 d、28 d劈裂强度最高(5.91 MPa、6.91 MPa),在全部试验组合中为最佳配比为A2B3C1D2。

Based on Orthogonal design, the compressive strength and splitting strength of recycled aggregate concrete(comprised with a mixture of flying ash for straw, graphene, basalt fiber and steel slag) with a replacement rate of 25% are chosen as assessing indices to study their impact on compressive strength and splitting strength of the recycled concrete. The results show that: the impact of addition of steel slag D, graphene B, straw flying ash A on the compressive strength and splitting strength remain the same. With increasing of the content of additive, the strength of recycled concrete experienced an initial increasing and then decreasing trend, and when the content of additive reaching double levels, the strength of the concrete reached its peak values in strength. The compressive strength of the recycled concrete exhibit a gradual increasing trend as its additive C increasing. Both additive C and additive B exerted a significant impact on the prior strength of the recycled strength and with the content of the additives increasing the splitting strength of the recycled concrete experienced the same variation as trend of initial increasing and decreasing trend. With additive C increasing, the splitting strength of the recycled concrete exhibit a gradual decreasing trend. And the variance analysis(ANOVA) exhibited that when the straw flying ash content, graphene, basalt fiber and steel slag reaching 5%, 1.8%, 0.3% and 15%, respectively, the compressive strength of the recycled strength are 25.27 MPa with its curing time of 7 days and 34.28 MPa with its curing time of 28 days, and its corresponding splitting strength being 5.91 MPa and 6.91 MPa. And the optimal mixture of the concrete is A2B3C1D2.