Meso-scale simulations of size effect on concrete dynamic splitting tensile strength: Influence of aggregate content and maximum aggregate size

Considering the heterogeneity and strain-rate effects of meso-components, concrete was simulated as a three-phase composite and a 3D meso-scale numerical method was set up. The splitting tensile failure of 315 concrete cubic samples having different side lengths with different aggregate contents and maximum aggregate sizes (MAS) has been explored by using the meso-scale numerical approach. In addition, the effect of aggregate contents and MAS on dynamic mechanical properties and the corresponding dynamic size effect of concrete was analyzed. The simulation results indicate that the size effect on dynamic splitting tensile strength of concrete materials is closely associated with the applied strain-rates. Appropriate enhancement in aggregate contents and MAS can increase the nominal strengths of concrete under different strain-rates. Aggregate contents and MAS present obvious influences on the size effect of splitting tensile strengths under low(er) strain-rates while they perform little effect on the dynamic size effect under high(er) strain-rates. Furthermore, the developed static and dynamic unified size effect law (SD-SEL) for concrete materials can quantitatively predict the size effect on dynamic splitting tensile strength.