通过对不掺硅灰的新型超高性能混凝土的力学性能试验,分析了养护条件、钢纤维掺量和振捣方法对UHPC材料基本力学性能的影响。研究表明:用超细水泥替代硅灰可以制备出性能优良的新型UHPC;钢纤维体积掺量从0提高到1%、1.5%、2%、3%时,立方体抗压强度分别提高8.6%、17.5%、27.5%、35.7%,轴心抗压强度分别提高8.2%、21.5%、35.9%、43.3%,弯曲初裂强度分别提高9.6%、25.0%、41.1%、74.2%,钢纤维掺量对UHPC材料弯曲初裂强度的提高明显优于对抗压强度的提高;随着养护温度的提高,新型UHPC的力学性能得到明显的提高,且早期强度提高较快;浇筑时采用振动台振捣与自密实UHPC相比,材料的抗压强度和弯曲韧性均有所提高,但轴拉强度有所下降。
The a new kind of ultra-high performance concrete which mixes had no silica fume was tested, and the influence of content of steel fiber volume, curing treatment and vibrating method on the mechanical properties of ultra-high performance concrete was analyzed. The test results show that it is feasible to produce excellent performance ultra-high performance concrete using superfine cement replacement of silica fume;when steel fiber volume is increased from 0 to 1%, 1.5% ,2% and 3% ,the cube compressive strength is increased by 8.6%, 17.5% ,27.5% and 35.7% ,the compressive strength is increased by 8.2% ,21.5% ,35.9% and 43.3% ,and the first bending crack strength is increased by 9.6% ,25%,41.1% and 74.2% ;the improvement of the first bending crack strength for the increase of steel fiber volume is obviously higher than that of the compressive strength;with the curing temperature increasing,mechanical performance of ultra-high performance concrete is improved obviously;compared to self compacting ultra-high performance concrete, the ultra-high performance concrete vibrated with shaker vibration when pouring has higher compressive strength and flexural toughness, lower axis tensile strength however.