A THEORETICAL STUDY ON THE INFLUENCE OF AGGREGATE GRADATION ON THE TENSILE STRENGTH OF 2-DIMENSIONAL MODEL CONCRETE

The size effect and macroscopic mechanical nonlinearity of concrete are caused by its inherent heterogeneity. Considering the mesoscopic structure, concrete is treated as a composite material consisting of aggregate, mortar matrix and an interfacial transition zone (ITZ). The double-line elastic-damage model has been borrowed to describe the mechanical properties of the mortar matrix and the ITZs. Aggregate is assumed to be elastic, so it cannot be damaged. Then, a general expression of the length of the fracture crack propagation path and a theoretical solution for the uniaxial tensile strength for different graded concretes are established. Finally, the theoretical resolution is compared with the simulation results at meso-scale and the rationality of the theoretical formulae for crack length and tensile strength from the present work is thereby validated.