Numerical analysis of crack propagation in tension specimens of concrete considered as a 2D multicracked granular composite

Abstract

A B S T R A C T R !~ S U M 1 ~A numerical model is presented to study the mechanisms of microcrack propagation in concrete, the loaddisplacement response and the trajectories of the crack propagation in specimens under displacement control. The microstructure of concrete in this model is represented by a matrix, inclusions and pre-existing microcracks introduced around the inclusions. Both the matrix and the inclusions are assumed to be elastic, homogeneous brittle materials. The stiffness of the inclusions is considered to be three times higher than that of the matrix. Crack propagation in the numerically-generated concrete is controlled by fracture mechanics-based criteria and is calculated through the finite element method. The influence of the microstructure of concrete, the size and the distribution of grains, the properties of the interfacial zone between grains and the matrix, as well as the boundary conditions, on final crack patterns and loaddisplacement responses are investigated. The different appearance of the numerical load-displacement curves exhibiting the quasi-brittle behaviour observed in experiments is explained in terms of several points of view, especially the dynamic crack propagation. On pre'sente un module num&ique que l'on applique h l'~tude des m~canismes de la microfissuration du b~ton, de la r@onse en termes de courbe effort-d@lacement et des trajectoires de propagation des fissures clans des @rouvettes en d@lacement imposL La microstructure du bdton est repr~-sent~ par une matrice, des inclusions et des microfissures introduites clans la matrice autour des inclusions. Dans ce module, la matrice et les inclusions sont consid&~es comme &ant homogbnes, glastiques et fragiles. La rigiditd des inclusions est trois fois plus