MODELLING OF CONCRETE FRACTURE AT AGGREGATE LEVEL USING DEM BASED ON X-RAY μCT IMAGES OF INTERNAL STRUCTURE

The paper describes two-dimensional meso-scale numerical results of fracture in notched concrete beams under quasi-static three-point bending. Concrete was modelled as a random heterogeneous 4-phase material composed of aggregate particles, cement matrix, interfacial transitional zones (ITZs) and air voids. As a numerical approach, the discrete element method (DEM) was used. The concrete micro-structure in calculations was directly taken from real concrete specimens based on 3D x-ray micro-computed tomography images and 2D images by the scanning electron microscope (SEM). Attention was paid to the shape of a fracture zone between aggregate grains. In addition, the effect of properties of ITZs on fracture was studied.