Bermudez Manuel, Wen Kuo-Wei, Hung Chung-Chan
Department of Civil Engineering, National Cheng Kung University, 1 University Rd, Tainan City 701, Taiwan.
Materials (Basel). 2022 Feb 16;15(4):1485. doi: 10.3390/ma15041485.
Structural members made of ultra-high-performance concrete (UHPC) have been attractive to engineers and researchers due to their superior mechanical properties and durability. However, existing studies were focused on the behavior of UHPC members reinforced with micro straight steel fibers at a volume fraction between 1 and 3%. There is a lack of studies on the influence of different types and amounts of fibers on the shear behavior of UHPC structural members. The objective of the study was to experimentally investigate the shear behavior of UHPC beams with macro hooked-end steel (MHS) fibers and polyvinyl alcohol (PVA) fibers, which are two of the most used fibers for high-performance fiber-reinforced cementitious composites. The shear behavior of ten large-scale non-prestressed UHPC beams was studied. The experimental parameters included the shear span-to-effective depth ratio, the fiber volume fraction, and the type of fibers. It was found that both MHS fibers and PVA fibers were effective in enhancing the shear performance of the UHPC beams whether the shear transfer mechanism was governed by arch action or beam action. Moreover, the measurement results of the average crack spacing imply the distinct difference in the fiber bridging effects of the MHS fibers and PVA fibers in the UHPC beams.
由超高性能混凝土（UHPC）制成的结构构件因其优异的力学性能和耐久性而受到工程师和研究人员的关注。然而，现有研究主要集中在体积分数为1%至3%的微直钢纤维增强UHPC构件的性能上。对于不同类型和数量的纤维对UHPC结构构件抗剪性能的影响，研究较少。本研究的目的是通过试验研究超高性能混凝土梁在配有大尺寸带钩端钢（MHS）纤维和聚乙烯醇（PVA）纤维时的抗剪性能，这两种纤维是高性能纤维增强水泥基复合材料中最常用的两种纤维。研究了十根大型非预应力UHPC梁的抗剪性能。试验参数包括剪跨比、纤维体积分数和纤维类型。结果发现，无论是拱作用还是梁作用控制抗剪传递机制，MHS纤维和PVA纤维都能有效提高UHPC梁的抗剪性能。此外，平均裂缝间距的测量结果表明，MHS纤维和PVA纤维在UHPC梁中的纤维桥接效应存在明显差异。
