An experimental study of the splitting tensile strength and cubic compressive strength of thread-typed steel fiber reinforced ultra high strength concrete（C100） was carried out.Effects of steel fiber were analyzed on the enhanced toughness and ratio between splitting tensile strength and compressive strength.The dimensions of cubic specimens were 100 mm×100 mm×100 mm and steel fibers were added at the volume fractions of 0,0.50%,0.75%,1.00% and 1.50%.The research results show that cracks developing path of ultra high strength concrete cubic specimens is more and cracks are scattered,but specimens are not broken,and the compressive toughness is enhanced with an addition of steel fiber.Besides,the compressive strength increases by 10.6%-15.5%,splitting strength increases by 38.2%-91.9% and ratio between splitting tensile strength and compressive strength is 0.060 5-0.084 6,increases by 24.08%-73.46% after steel fibers are added.The prediction models for splitting tensile strength and compressive strength are presented and errors of predicted and measured values are ±1.79% and ±17.84% respectively.Conclusions are drawn that marked brittleness and bad toughness can be overcome by an addition of steel fibers for ultra high strength concrete.%在超高强混凝土（C100级）中掺入螺纹型钢纤维,通过立方体抗压强度与劈裂抗拉强度试验,研究钢纤维对超高强混凝土增强增韧效果和拉压比性能的影响.立方体试件尺寸为100mm×100mm×100mm,钢纤维掺量为0、0.50%、0.75%、1.00%、1.50%.试验结果表明,掺入钢纤维后,超高强混凝土立方体试件裂缝开展路径较多,裂而不散,坏而不碎,抗压韧性显著增强;抗压强度提高10.6%～15.5%,劈裂抗拉强度提高38.2%～91.9%;掺入钢纤维的超高强混凝土拉压比为0.060 5～0.084 6,拉压比提高24.08%～73.46%.提出了钢纤维超高强混凝土立方体抗压强度与劈裂抗拉强度预测模型,预测值与试验值误差分别在±1.79%、±17.84%范围内.掺入钢纤维可使超高强混凝土脆性大、韧性小的缺点得到显著改善.
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