聚丙烯-钢纤维/再生粗骨料混凝土力学性能正交试验研究

Orthogonal experimental study on the mechanical properties ofpolypropylene-steel fiber/recycled coarse aggregate concrete

基于L_(16)(4^(5))正交表设计16组聚丙烯-钢纤维/再生粗骨料混凝土(PP-SF/RCA混凝土)和1组基准组混凝土的7 d抗压强度和28 d抗压、劈拉及弯折强度试验,研究V_(P)、V_(S)和R_(R)三因素对PP-SF/RCA混凝土力学性能的影响。结果表明,PP-SF/RCA混凝土的7 d抗压强度和28 d抗压、劈拉及弯折强度均大于基准组,较基准组最大增幅分别为41.9%、23.0%、59.1%和28.9%;7和28 d抗压强度随V_(P)、V_(S)和R_(R)的变化趋势相似,但7 d抗压强度的方差分析结果不显著;对于28 d抗压强度,V_(P)和R_(R)为特别显著因素;对于28 d劈拉强度,V_(S)为显著因素;对于28 d弯折强度,V_(S)和R_(R)为显著因素;采用功效系数法对28 d抗压、劈拉及弯折强度试验结果进行综合评价,建议最佳配合比为0.04%的V_(P)、2.0%的V_(S)、80%的R_(R);引用纤维混杂效应理论建立的28 d抗压、劈拉及弯折强度预测模型精度较高。

Based on the L_(16)(4^(5))orthogonal table,16 groups of polypropylene-steel fiber/recycled coarse aggregate concrete(PP-SF/RCA concrete)and 1 group of reference group concrete are obtained,and the 7-day compressive strength and 28-day compressive,split tensile and bending strength tests are designed.The flexural strength test is to study the influence of the three factors of V_(P),V_(S) and R_(R) on the mechanical properties of PP-SF/RCA concrete.The results show that the 7-day compressive strength and 28-day compressive,split tensile and bending strengths of PP-SF/RCA concrete are greater than those of the benchmark group,and the largest increases compared to the benchmark group are 41.9%,23.0%,59.1%and 28.9%,respectively.The change trend of 7-day compressive strength with V_(P),V_(S) and R_(R) is similar to that of 28-day compressive strength,but the variance analysis result of 7-day compressive strength is not significant.For 28-day compressive strength,V_(P) and R_(R) are particularly significant factors.For 28-day split tensile strength,V_(S) is significant factors.For 28d bending strength,V_(S) and R_(R) are significant factors.The efficiency coefficient method is used to comprehensively evaluate the 28-day compression,splitting and bending strength test results,and the best mix ratio is 0.04%V_(P),2.0%V_(S),80%R_(R).28d compression,splitting and bending strength prediction model established by the theory of fiber hybrid effect has high accuracy.