多因素对自密实混凝土力学性能发展趋势的影响

The influence of many factors on the development trend of the mechanical properties of self-compacting concrete

采用正交试验分析微波加热改性次数、再生粗骨料替代率、钢渣砂替代率及聚丙烯纤维掺量这4种因素对自密实混凝土力学性能的影响。结果表明,钢渣砂替代率对抗压、劈拉及弯折强度影响显著,再生粗骨料替代率对抗压及劈拉强度影响显著,微波加热改性次数和聚丙烯纤维掺量对强度影响较小;微波加热改性对提升再生粗骨料的品质存在一定促进作用,但作用不显著,且实施工序耗时费力,难以满足工业化生产要求;综合衡量极差及方差分析结果可得最佳配合比为10次微波加热改性、70%再生粗骨料替代率、45%钢渣砂替代率和0.10%聚丙烯纤维掺量;通过非线性回归拟合得到的劈拉及弯折强度与抗压强度之间的新关系式与其他学者建立的关系式进行比较,提出的新关系式与试验数据吻合较好,有一定参考价值。

Orthogonal test was used to analyze the influence of four factors on the mechanical properties of self-compacting concrete:the number of microwave heating modification,the replacement rate of recycled coarse aggregate,the replacement rate of steel slag sand and the content of polypropylene fiber.The results show that the replacement rate of steel slag sand has a significant effect on compressive strength,splitting strength and bending strength,the replacement rate of recycled coarse aggregate has a significant effect on compressive strength and splitting strength,and the microwave modification times and polypropylene fiber content have little effect on strength.Microwave heating modification can improve the quality of reclaimed coarse aggregate to some extent,but the effect is not significant,and the implementation process is time-consuming and laborious,which is difficult to meet the requirements of industrial production.According to the results of measuring range and variance analysis,the optimal mixture ratio is 10 times microwave heating modification,70%regenerated coarse aggregate replacement ratio,45%steel slag sand replacement ratio and 0.10%polypropylene fiber content.The new relationship between tensile strength,bending strength and compressive strength obtained by nonlinear regression fitting is compared with that established by other scholars.It is found that the new relationship is in good agreement with the experimental data and has certain reference value.