钢纤维类型和掺量对高强混凝土流动性的影响

INFLUENCE OF STEEL FIBER FORMS AND DOSAGE ON FLUIDITY OF HIGH STRENGTH CONCRETE

钢纤维增强高强混凝土的流动性是评价混凝土工作性的重要参数之一。通过测试混凝土的坍落度并计算新拌混凝土的屈服应力,本文研究了钢纤维的类型和体积掺量对高强混凝土流动性的影响。结果表明,在四种钢纤维中,长度12~14mm、直径0.18~0.23mm的镀铜微丝钢纤维对混凝土的流动性影响最为显著,随着纤维体积掺量增大,混凝土坍落度显著下降。铣削型纤维对混凝土坍落度的影响最不明显,当纤维体积掺量为1.5%时,混凝土坍落度能达到190mm,屈服应力约为1KPa,仍能满足泵送要求。在取得最优增韧效果的基础上,可在1%~1.5%的范围内调整铣削型纤维的体积掺量。

Fluidity of steel fiber reinforced high strength concrete is one of the important parameters to evaluate the workability of concrete. Slumps were tested in this study and yield stresses of fresh concrete were calculated from slump. The influences of steel fiber forms and dosage on the fluidity of high strength concrete were discussed. The results show that copper covered steel fiber （CC） with the length of 12 - 14mm and diameter of 0. 18 - 0. 23mm has the most remarkable effect on fluidity of concrete. Slumps of fresh concrete decrease significantly with the increase of volume fraction of CC. The effect of milling fiber on the slump of concrete is the least obvious. When the fiber volume is 1.5%, the concrete slump can reach 190mm and the yield stress is about lkPa, which can meet the requirement of pumping On the basis of obtaining the optimal toughening effect, the volume of milling fiber can be adjusted in the range of 1% - 1.5%.