砂率对剪切型钢纤维增强混凝土性能的影响

试验研究了用水量、水灰比、钢纤维长度和体积分数变化条件下砂率对薄板剪切型钢纤维增强混凝土的拌和物工作性及立方体抗压强度和劈裂抗拉强度的影响规律.结果表明:钢纤维在基体混凝土拌和物中的“棚架”效应导致了钢纤维混凝土拌和物的坍落度降低,在基体混凝土易于振动成型的情况下,这种效应迅速减弱而不明显影响钢纤维混凝土的振动成型.随着砂率的增大,钢纤维混凝土的拌和物坍落度及立方体抗压强度和劈裂抗拉强度呈现先增大后减小的规律.提出了薄板剪切型钢纤维增强混凝土的合理砂率取值与配合比设计的建议.

Effect of Sand Ratio on Thin-Plate Shearing Steel Fiber Reinforced Concrete

The steel fiber reinforced concrete(SFRC) was made using the method in which the steel fiber was directly added into concrete mixture.Under conditions of changing the water demand,the water-cement ratio,the length of steel fiber and the volume fraction of fiber,tests were carried out to study the effects of the sand ratio on mixture workability,cubic compressive strength and splitting tensile strength of thin-plate shearing steel fiber reinforced concrete.It is proved that the rack-type effect of steel fiber in the concrete mixture causes the decrease of mixture slump,this effect is rapidly weakened and does not much influence the vibration of steel fiber reinforced concrete if the concrete mixture is easy to vibrate.With increasing sand ratio,the slump,cubic compressive strength and splitting tensile strength of steel fiber reinforced concrete have the tendency of increasing first and then decreasing.The reasonable values of sand ratio and the mixture design method of thin-plate shearing steel fiber reinforced concrete are proposed.