钢纤维搭配对超高性能混凝土拌合物性能的影响

通过设计不同水胶比、钢纤维掺量下超高性能混凝土(UHPC)配合比,比较了T₂₀₀与min-v漏出时间和流动度的关系,发现T₂₀₀能较好反映UHPC黏度的变化,与流动度共同表征UHPC的流变性能。采用较短纤维替代长纤维,其质量比小于0.75时,随着短纤维的加入能降低UHPC的黏度;当超过0.75后,长短钢纤维的"墙体效应"作用对流动度的贡献作用降低明显。长短纤维搭配能提高UHPC的综合性能。随着纤维影响因素(k)的增加,流动度先增加后降低;k值的变化与抗压强度和抗折强度呈良好的线性关系。

The Influence of Steel Fiber Mixing on Properties of UHPC Mixture

By designing the ratio of ultra high performance concrete(UHPC)under different water-to-binder ratio and steel fiber content,the relationship between T200 and min-v leakage time and fluidity was compared.It was found that T200 can better reflect the change of UHPC viscosity.T200 and fluidity can reflect the rheological properties of UHPC.Short fiber was used to replace long fiber.When the mass ratio of long fiber and short fiber is less than 0.75,the viscosity of UHPC can be reduced with the addition of short fiber.When it exceeds 0.75,the effect of wall effect of long and short steel fiber on fluidity is obviously reduced.The combination of long and short fibers can improve the overall performance of UHPC.With the increase of fiber influencing factor(k),the fluidity increases first and then decreases;the change of k value has a good linear growth relationship with compressive strength and flexural strength.