纤维定向布放钢纤维混凝土力学性能及断裂过程细观分析

Mesoscopic Analysis of Mechanical Properties and Fracture Process of Aligned Steel Fiber Reinforced Concrete

钢纤维的适量掺入使得钢纤维混凝土力学性能有显著提高。基于试验配合比随机生成二维钢纤维混凝土梁细观模型,对体积分数相同的钢纤维分别采用随机乱向分布、受拉区水平定向布放和沿最大主拉应力布放3种方式进行建模研究,结合黏结裂缝模型,对钢纤维混凝土梁抗弯试验进行了数值模拟,分析了钢纤维掺量和取向对钢纤维混凝土的力学性能影响。将数值计算结果与已有试验结果进行对比分析,结果表明,钢纤维定向布放可以大幅度提高混凝土抗弯性能及断裂过程阻裂增韧效果。

The mechanical properties of steel fiber reinforced concrete(SFRC)can be significantly improved by adding steel fiber.Based on the experimental mix ratio,the 2D mesoscopic model of steel fiber reinforced concrete beams is randomly generated,in these beams,the steel fiber with same volume fraction are distributed using three methods of random direction,horizontally oriented in tensile zone and along the maximum principal tensile stress respectively.Combined with cohesive crack model,the bending experiments of these three kinds of steel fiber reinforced concrete beams are numerically simulated to analysis the influences of steel fiber content and orientation on the mechanical property of steel fiber reinforced concrete.The numerical calculation results are compared with existing experimental results,and the comparison shows that the directional arrangement of steel fiber can greatly improve the bending capacity of concrete and the effect of crack resistance and toughness during the fracture process.