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为研究长、短钢纤维对超高性能混凝土(UHPC)受弯力学性能的影响,设计、制作了13组标准养护条件下的UHPC试件,其中3组为掺单一型短钢纤维,其他组均为掺混杂型钢纤维,对其进行立方体抗压及四点抗折试验。试验结果表明:对于掺加单一型短钢纤维的UHPC,钢纤维体积掺量为5%时,抗折强度最大,为19.98MPa,继续增加钢纤维掺量,抗折强度反而降低;掺混杂型钢纤维的UHPC比单一型的抗折强度高,并且当长、短钢纤维体积掺量分别为2%和1%时,抗折强度达到最大,为23.55MPa;UHPC的受弯力学性能主要受长纤维的影响,短纤维影响较小;长纤维掺量对UHPC的抗折强度、延性以及抗弯韧性有一定影响,但是主要取决于长、短纤维的搭配,长、短纤维体积掺量最优搭配为2%和1%。
In order to study the influence of long and short steel fibers on the flexural mechanical properties of ultra-high performance concrete (UHPC), 13 UHPC specimens under standard curing conditions were designed and manufactured, of which 3 were single-type short steel fibers and the others Are mixed hybrid steel fiber, the cube compression and four-point bending test. The results show that for UHPC with a single type of short steel fiber, the flexural strength is the highest when the volume fraction of steel fiber is 5%, which is 19.98MPa. Increasing the content of steel fiber decreases the flexural strength but decreases; The flexural strength of UHPC fiber is higher than that of single type, and the flexural strength reaches the maximum at 23.55MPa when the volume fraction of long and short steel fiber is 2% and 1% respectively. The flexural mechanical properties of UHPC are mainly affected by the flexural strength The influence of short fiber is small. The long fiber content has certain influence on the flexural strength, ductility and flexural toughness of UHPC, but mainly depends on the combination of long and short fibers, and the optimal volume and volume of long and short fibers With 2% and 1%.