玄武岩纤维增强赤泥基混凝土力学性能研究

Study on the Mechanical Properties of Basalt Fibre Reinforced Red Mud-Based Concrete

为了提升赤泥综合利用率,改善赤泥基混凝土(RMC)力学性能,以20%赤泥粉体替代水泥,研究了不同玄武岩纤维(BF)掺量(0.1%、0.2%和0.3%)和长度(12 mm、18 mm和24 mm)对RMC流动性、立方体抗压强度和抗折强度的影响规律,并通过多元回归分析建立了强度预测模型。结果表明,掺入BF降低了RMC流动性;适量BF对RMC抗压强度具有一定提升作用,其最优掺量范围为0.1%~0.2%;BF长度对RMC抗压性能表现出不同的影响规律,B4试样28 d抗压强度达到最大值46.6 MPa。随着BF掺量的增加,RMC抗折强度明显升高,但提升效果随长度的增加而减弱,B3试样28 d抗折强度达到最大值5.5 MPa,较RMC提升31.0%;同时,随着BF掺量增大,BFRMC折压比呈上升趋势,韧性改善效果越明显。强度预测模型结果表明28 d抗压和抗折强度预测值与试验值最大误差分别为3.29%和2.86%,与试验结果吻合较好,抗压强度模型预测的最优组合为纤维长度16 mm和掺量0.12%,最高抗压强度为46.0 MPa。

In order to improve the comprehensive utilization rate of red mud and the mechanical properties of red mud-based concrete(RMC),20%red mud powder was used to replace cement,the effects of different BF content(0.1%,0.2%and 0.3%)and BF length(12 mm,18 mm and 24 mm)on the fluidity,cubic compressive strength and flexural strength of RMC were studied,and the strength prediction model was established by the multiple regression analysis./The results showed that BF incorporation reduced the fluidity of RMC,the appropriate amount of BF had a certain improvement on the compressive strength of RMC,and its optimal content range located in the ranges from 0.1%-0.2%.The length of BF exhibited different effects on the compressive performance of RMC.The 28 d compressive strength of B4 sample reaches the maximum value of 46.6 MPa.With the increase of BF content,the flexural strength increased obviously,but the improvement effect decreased with the increase of BF length.The 28 d flexural strength of B3 sample reached the maximum value of 5.5 MPa,which was 31.0%higher than that of RMC.Meanwhile,with the increase of BF content,the ratio of flexural strength to compressive strength of BFRMC showed an increase trend,and the toughness improvement effect of BFRMC was more significant.The results of the strength prediction models showed that the maximum errors between the predicted and experimental values of 28 d compressive and flexural strength were 3.29%and 2.86%,respectively,which well agreed with the experimental results.The optimal combination predicted by the compressive strength model was the fiber length of 16 mm and the content of 0.12%,and the maximum compressive strength reached 46.0 MPa.