混凝土细观尺度下单轴拉伸性能研究

Axial Tensile Properties of Concrete Meso-Scale

采用蒙特卡罗方法生成不同骨料形状的二维混凝土试件模型,对不同骨料形状、骨料分布、骨料含量、初始缺陷与界面层厚度等条件下的混凝土试件进行单轴拉伸分析。结果表明:骨料形状的不同对试件拉伸性能影响较大,碎石形骨料试件会较早出现应力集中,圆滑的骨料边缘可以改善试件应力分布,提高混凝土试件抗拉性能;骨料分布不同与界面厚度不同对混凝土单轴拉伸性能的影响可以忽略;初始缺陷的增加会导致试件弹性模量、抗拉强度及峰值拉应变减小;混凝土材料的不均匀性使其在承受逐级增大的荷载时产生不均匀变形和应力。

Using the Monte Carlo method to generate two-dimensional pebbles and gravel aggregate concrete specimen model, the paper analyzed the uni- axial tension of the concrete specimen under the conditions of different aggregate shape, aggregate distribution, aggregate content, initial defects and the in- terface layer thickness. The results show that： a ）the aggregate shape difference has greater impact on the tensile properties of the specimens, gravel-shaped aggregates specimen will cause stress concentration earlier, the sleek the aggregate edge can improve stress distribution of the specimen, to improve tensile properties; b）the impact of different distribution of the aggregate and interface thickness on uniaxially stretched performance can be ignored; c）the in- crease of the initial defect will cause the reduction of the elastic modulus of the test piece, the tensile strength and peak tensile strain; d） because of inho- mogeneity of concrete material, uneven deformation and stress will be generated with progressively increasing load to bear.