织物增强混凝土的纤维协同等代效应对约束混凝土的影响分析

通过ABAQUS对织物增强混凝土拉伸性能及其永久模壳加固混凝土柱的轴压性能进行了数值分析,在材料层面研究了短纤维掺量、纤维织物层数对水泥基复合材料(ECC)和超高性能混凝土(UHPC)拉伸性能的影响; 在结构层面研究织物增强超高性能混凝土模壳对不同强度核心区混凝土的约束效率及纤维织物和短纤维间的替代关系。结果表明:织物合理的替代部分短纤维能够进一步提升材料的拉伸性能,对于适宜的短纤维掺量会使纤维分散程度更好,获得更高的开裂强度,与织物取得更好的协同效应,同时织物的存在显著提升了基体的应变硬化,带来了更高的极限强度,并明显改善了UHPC的延性; 材料性能的提升随之反映在结构方面性能的提升,随着纤维织物层数的增加,模壳能明显提升加固柱的承载力和延性; 相同条件下模壳对高强度混凝土的约束提升效率降低,对于该研究模型,2层碳纤维增强复合材料(CFRP)织物能够充分取代5%体积含量的钢纤维,并在加固普通混凝土柱时取得更优异的性能。

Influence Analysis of Fiber Synergistic Equivalent Effect of Textile Reinforced Concrete on Confined Concrete

ABAQUS was used to analyze the tensile properties of textile reinforced concrete(TRC)and the axial compression performance of concrete columns strengthened with TRC permanent formwork, the effects of short fiber content and fabric layers on the tensile properties of engineered cementitious composite(ECC)and ultra high performance concrete(UHPC)were studied. At the structural level, the restraint efficiency of TRC formwork to different strength core concrete and the substitution relationship between textile and short fiber were studied. The results show that the reasonable substitution of textile for short fiber can further improve the tensile properties of the material. For the appropriate amount of short fiber, the dispersion degree of fiber is better, the cracking strength is higher, and the synergistic effect with fabric is better. At the same time, the existence of fabric can significantly enhance the strain hardening of matrix, bring higher ultimate strength, and significantly improve the ductility of UHPC. The material performance is reflected in the improvement of structural performance. With the increase of fabric layers, the TRC formwork can significantly improve the bearing capacity and ductility of the reinforced column. While under the same conditions, the efficiency of the formwork to restrain the high-strength concrete is reduced. For the research model, 2-layer CFRP fabric can fully replace 5% volume fraction of steel fiber, and achieve better performance in strengthening concrete columns.