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超高性能纤维混凝土具有高强度(抗压、抗拉)、高延性和高耐久性的优势,但其抗拉强度仍远低于抗压强度。将端钩型和哑铃型钢纤维按不同比例混合,采取自密实成型和常温标准养护方法,试验研究了配置440MPa纵向钢筋的超高性能纤维混凝土梁。通过12根梁的静载试验,研究了钢纤维体积率为2.0%和2.5%时,不同纤维混合比例的钢筋超高性能纤维混凝土梁的力学性能。试验结果表明:加入钢纤维后梁的极限荷载和延性显著提高;在纤维体积率2.0%时,钢筋超高性能纤维混凝土梁比配筋相同的钢筋混凝土梁承载力提高20%～41%,延性系数提高3.9～6.7倍。钢筋端钩纤维混凝土梁的承载力和延性较钢筋混凝土梁分别提高39%和5.1倍,钢筋哑铃纤维混凝土梁的承载力和延性分别提高20%和3.9倍;钢筋混合纤维混凝土梁的承载力介于钢筋端钩和钢筋哑铃纤维混凝土梁之间。参照现行规范提出了钢筋超高性能纤维混凝土梁正截面极限弯矩的计算方法,计算结果与试验结果吻合较好。
Ultra-high-performance fiber reinforced concrete has the advantages of high strength (compression, tensile), high ductility and high durability, but its tensile strength is still far below the compressive strength. The end hook type and dumbbell steel fibers were mixed according to different proportions, and self-compacting and normal temperature curing methods were adopted. The ultra-high performance fiber reinforced concrete beam with 440MPa longitudinal reinforcement was tested. Through the static load test of 12 beams, the mechanical properties of steel fiber reinforced ultra high performance fiber reinforced concrete beam with different fiber mixing ratio were studied when the volume fraction of steel fiber was 2.0% and 2.5%. The experimental results show that the ultimate load and ductility of the beam are significantly increased when the steel fiber is added. The load-bearing capacity of the SRHC beam is about 20% ~ 41% higher than that of the same reinforced fiber reinforced concrete beam with the fiber volume fraction of 2.0% Improve 3.9 to 6.7 times. The carrying capacity and ductility of reinforced concrete beam with end hooks are 39% and 5.1 times higher than those of reinforced concrete beams, respectively. The bearing capacity and ductility of reinforced dumbbell fiber reinforced concrete beams are increased by 20% and 3.9% respectively. The bearing capacity of reinforced concrete beam with fiberglass reinforced concrete Between the steel end hook and steel bar dumbbell fiber reinforced concrete beam. With reference to the current codes, the calculation method of the ultimate cross-section bending moment of reinforced ultra-high performance fiber reinforced concrete beam is proposed. The calculated results are in good agreement with the experimental results.