多孔混凝土裂缝扩展三维数值模拟

3D NUMERICAL SIMULATION OF CRACK PROPAGATION OF POROUS CONCRETE

采用数字图像技术及MATLAB程序,将多孔混凝土切面的二维图像处理为代表骨料与砂浆的二维矩阵,利用有限元软件建立了基于真实细观结构的多孔混凝土三维数值模型,对多孔混凝土在单轴受压作用下的裂纹扩展、贯通及破坏的过程进行演化模拟。结果表明:压应力通过骨料纵向传播,上层存在孔隙的骨料区会产生拉应力。裂缝最早发生在开口孔隙边缘的骨料上和骨料与砂浆的粘结薄弱区,然后沿骨料边缘扩展,并与孔隙贯通,直至失稳破坏。

This paper transformed the two dimension images of porous concrete section to two- dimensional matrix which representing the aggregate and mortar by using digital image technology and MATLAB program. Then it used the finite element software to establish a three-dimensional numerical model with actual meso-structure of the porous concrete. Crack propagation process and failure model of the porous concrete under uniaxial compression loadings are simulated. The results show： compressive stress spread through aggregate vertically, aggregate area with pore in the above would cause tensile stress. The earliest occurrence of cracks is in the weak bonding area of the aggregate and mortar, or the aggregate on the edge of open pore. Then the crack developed along the edge of aggregate and cutting through with the pore until the instability and damage of porous concrete.