Effect of fractal dimension in concrete meso-structure on its axial mechanical behavior: A numerical case study

The numerical meso-modeling method is a powerful tool for simulating concrete and studying the influence of the geometric form of meso-structure on its mechanical behavior. It is still uncertain how to most effectively characterize the geometric form of the concrete meso-structure and its effect on the observed macro behavior. In this study, the fractal dimension of cement paste was used to describe the geometric form of concrete at the meso-level. A group of meso-models of concrete with various fractal dimensions and coarse aggregate contents were simulated using the Random Fractal Modeling method, and the numerical results under compression and tension were studied and discussed. The simulation results suggested that the compressive initial modulus, the compressive strength decreased, the strain corresponding to the maximum compressive stress decreased with increasing fractal dimension. However, the fractal dimension did not influence the tensile initial modulus, the tensile strength, and the strain corresponding to the maximum tensile stress obviously. The comprehensive consideration of the fractal characterize can provide a reasonable tool for understanding and predicting the observed macroscopic behavior of concrete.