混杂钢纤维对UHPC弯曲性能的影响研究

Study on the effect of blended steel fiber on the bending property of UHPC

将不同长度(8、13、16、20 mm)的平直型钢纤维(SF)、波纹型SF分别与长度为13 mm的端钩型SF混掺到UHPC中,研究了不同SF混杂组合对UHPC试件扩展度、抗弯强度和弯曲韧性的影响。结果表明:增加平直型SF和波纹型SF的长度降低了混杂纤维UHPC的扩展度;在受荷初期,UHPC基体与SF共同承受外力,且前者是主要承受者,当UHPC基体开裂后,横跨裂缝的SF成为外力的主要承受者;随着平直型SF和波纹型SF长度的增加,混杂纤维UHPC试件的抗弯强度、峰值挠度基本上呈逐渐增大趋势,弯曲韧性先降低后升高。

Flat type and corrugated type steel fibers(SF)of different lengths(8,13,16,20 mm)were blended with end hooked type SF of length of 13 mm into UHPC,respectively,and the effects of different SF hybrid combinations on the extensibility,bending strength and bending toughness of UHPC specimens were investigated.The results show that increasing the length of flat type SF and corrugated type SF leads to a decrease in the extensibility of UHPC with hybrid fibers.At the initial stage of loading,the UHPC matrix and SF share the external force,of which the former is the main bearer,and when the UHPC matrix cracks,the SF across the crack becomes the main bearer of the external force.With the increase of the length of the flat type SF and corrugated type SF,the bending strength and peak deflection of UHPC specimens with hybrid fibers basically tends to increase gradually,and the bending toughness first decreases and then increases.