单一及混杂网格增强ECC板抗弯性能

    Flexural Performance of ECC Panels Reinforced by Single and Hybrid Mesh

    • 摘要: 纤维网格增强工程用水泥基复合材料(engineered cementitious composite, ECC)具有质量轻、延性高、耐久性好等特性, 然而, 单一纤维网格在同时提高抗弯承载和变形能力方面存在局限性。为解决这一问题, 通过四点弯曲试验研究单一及混杂网格增强ECC板的弯曲性能, 设计了1个无网格ECC对照板、4个单一纤维网格增强ECC板、3个碳纤维与玻璃纤维网格混杂增强ECC板和3个碳纤维网格与钢丝网格混杂增强ECC板。研究了网格层数、种类和混杂方式对ECC板的抗弯承载能力与变形能力的影响规律。试验结果表明: 碳纤维-钢丝网格混杂板在试件开裂后充分发挥了碳纤维网格高抗拉强度和ECC应变硬化的优点, 显著提高了网格强度利用率和变形能力。网格层数均为2层时, 碳-玻璃纤维网格混杂板较单一玻璃纤维网格板的承载能力提升11.98%, 变形能力提升13.07%;碳纤维-钢丝网格混杂板的变形能力相较于单一碳纤维网格板提升135.20%。网格层数均为3层时, 2层碳纤维网格与1层玻璃纤维网格混杂板的变形能力相较于单一碳纤维网格板提升140.89%;1层碳纤维网格与2层钢丝网格混杂板相较于1层碳纤维网格与2层玻璃纤维网格混杂板的承载能力提升9.82%, 变形能力提升8.23%。碳纤维-钢丝网格混杂板的综合弯曲性能最优, 相较于碳-玻璃纤维网格混杂板, 其抗弯承载能力相似, 变形能力优于后者。相较于单一纤维网格板和碳-玻璃纤维网格混杂板, 碳纤维-钢丝网格混杂会使试件在峰值荷载后承载力下降趋于缓慢。基于试验结果, 建立了抗弯承载力计算公式, 计算值与试验值吻合良好。

       

      Abstract: Fiber mesh reinforced engineered cementitious composite (ECC) has the properties of high ductility, lightweight, and good durability; however, a single-fiber mesh has limitations in simultaneously improving flexural load and deformation capacity. To solve this problem, tests were conducted to investigate the flexural properties of single and hybrid mesh-reinforced ECC panels through four-point bending tests, and one meshless ECC control panel, four single-fiber mesh-reinforced ECC panels, three carbon and glass fiber mesh hybrid-reinforced ECC panels, and three carbon fiber mesh and steel wire mesh hybrid-reinforced ECC panels were designed. The effects of mesh layers number, types, and mixing methods on the flexural load-carrying capacity and deformation capacity of ECC panels were investigated. The test results show that the carbon fiber-wire mesh hybrid plate gives full play to the advantages of high tensile strength of the carbon fiber mesh and strain hardening of the ECC after the specimen is cracked, which significantly improves the utilization rate of the mesh strength and deformation capacity. When the number of mesh layers is 2, the load-carrying capacity of carbon-glass fiber mesh hybrid plate is increased by 11.98% and the deformation capacity is increased by 13.07% compared with the single glass fiber mesh plate; the deformation capacity of carbon fiber-steel wire mesh hybrid plate is increased by 135.20% compared with the single carbon fiber mesh plate. When the number of mesh layers is 3, the deformation capacity of 2-layer carbon fiber mesh and 1-layer glass fiber mesh hybrid board is 140.89% higher than that of single carbon fiber mesh board; 1-layer carbon fiber mesh and 2-layer steel wire mesh hybrid board are 9.82% higher than that of 1-layer carbon fiber mesh and 2-layer glass fiber mesh hybrid board in terms of carrying capacity, and the deformation capacity is 8.23% higher. The carbon fiber-wire mesh hybrid panel has the best overall bending performance, with similar bending load capacity and better deformation capacity than the carbon-glass fiber mesh hybrid panel. Compared with the single-fiber mesh plate and the carbon-glass fiber mesh hybrid plate, the carbon-wire mesh hybrid tends to slow down the decrease of the specimen's load capacity after the peak load. Based on the test results, a formula for calculating the flexural load capacity was established, and the calculated values agree well with the test values.

       

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