基于不同优化目标的钢纤维混凝土 力学性能试验

Mechanical properties of steel fiber reinforced concrete based on different optimization objectives

为研究不同优化目标钢纤维混凝土的制备方法,并提高其力学性能,通过正交试验研究混凝土的砂率、钢纤维掺量、钢纤维长度及骨胶比对混凝土性能的影响,提出不同优化目标下钢纤维混凝土配合比设计建议值,对不同掺量的钢纤维混凝土分别进行工作性能、轴心抗压强度及三点弯抗折试验。研究结果表明:混凝土的骨胶比和砂率对混凝土坍落度及扩展度影响更加显著,而钢纤维的参数对于混凝土抗压及抗折强度的影响更加显著;以功效系数法为优化目标得到的钢纤维混凝土抗压强度提高了14.8%,比例极限提高13.3%,延性系数提高3.4%,混凝土塑性破坏特征进一步缓解,且抗折强度略有提高,断裂能提高了30%,抗变形性能及弯曲韧性明显增大;以抗压强度最大为优化目标得到的钢纤维混凝土抗压强度提高了28%,比例极限提高了33.4%,但其延性系数下降5.2%,混凝土塑性破坏有所加剧,且抗折强度下降了2.6%,断裂能下降41%,混凝土抗变形性能及弯曲韧性明显不足。

To study the preparation methods and mechanical properties of steel fiber reinforced concrete with different optimization objectives,this paper presents the optimized target steel fiber concrete mixture ratio design of the different values to compare different optimization goal of steel fiber reinforced concrete performance difference for working performance,axial compressive strength,and three-point bending test by the way of orthogonal experiment study of sand ratio,dosage of steel fiber concrete,steel fiber length and bone glue ratio on the performance of concrete.The results show that the bone-binder ratio and sand ratio of concrete have more significant effects on the collapse and expansion of concrete,while the steel fiber parameters get more remarkable effects on the compressive strength and flexural strength of concrete.The compressive strength,proportional limit and ductility coefficient of SFRC obtained by the efficiency coefficient method increase by 14.8%,13.3%and 3.4%respectively.The plastic failure characteristics of SFRC are further alleviated,the flexural strength is slightly improved and the fracture energy increases 30%,and the deformation resistance and bending toughness are significantly enhanced.The compressive strength and proportional limit of steel fiber reinforced concrete obtained by the optimal goal of maximum compressive strength are increased by 28%and 33.4%,but the ductility coefficient is decreased by 5.2%,the plastic failure of concrete is aggravated,the flexural strength is decreased by 2.6%and the fracture energy is decreased by 41%,and the deformation resistance and bending toughness of concrete are obviously insufficient.