Mesoscale modelling of size effect on the evolution of fracture process zone in concrete

A comprehensive mesoscopic investigation has been conducted to examine the evolution of fracture process zone (FPZ), using notched plain concrete beams subjected three-point bending as a generic representation. The are modelled random heterogeneous materials containing three components, namely coarse aggregates, mortar and interface transition (ITZ). To better represent in concrete, coupled cohesive-contact approach is employed model crack initiation, propagation friction mechanisms during process. Thus, FPZ naturally captured simulation composed by microcracks along ITZ or through matrix mesoscale model. macroscopic response load-deformation curves well shapes sizes calculated from numerical results validated against experimental observations good agreement achieved. Subsequent modelling demonstrate that tend exhibit main multiple secondary microcracks. During growth crack, new initiate while some formed earlier stop growing even close. path strongly irregular due spatial distribution aggregate particles with weak ITZs. influence size effect on also investigated simulation. Results show width insensitive beam but length dependent size, such characteristics deemed be intrinsic reasons for overall phenomenon structures.