Meso-scale approach to modelling the fracture process zone of concrete subjected to uniaxial tension

TL;DR

This paper develops a meso-scale model of concrete's fracture process zone under uniaxial tension, using a lattice approach to simulate the response of aggregates, matrix, and interfaces, and calibrates a nonlocal model based on these results.

Contribution

It introduces a meso-scale analysis method for concrete fracture zones and calibrates a nonlocal model from detailed lattice simulations.

Findings

Determined the spatial distribution of dissipated energy density.

Estimated the size and shape of the fracture process zone.

Calibrated a nonlocal fracture model using meso-scale analysis results.

Abstract

A meso-scale analysis is performed to determine the fracture process zone of concrete subjected to uniaxial tension. The meso-structure of concrete is idealised as stiff aggregates embedded in a soft matrix and separated by weak interfaces. The mechanical response of the matrix, the inclusions and the interface between the matrix and the inclusions is modelled by a discrete lattice approach. The inelastic response of the lattice elements is described by a damage approach, which corresponds to a continuous reduction of the stiffness of the springs. The fracture process in uniaxial tension is approximated by an analysis of a two-dimensional cell with periodic boundary conditions. The spatial distribution of dissipated energy density at the meso-scale of concrete is determined. The size and shape of the deterministic FPZ is obtained as the average of random meso-scale analyses. Additionally, periodicity of the discretisation is prescribed to avoid influences of the boundaries of the periodic cell on fracture patterns. The results of these analyses are then used to calibrate an integral-type nonlocal model.