Study on the meso-scale numerical simulation method for flow behavior of fresh self-compacting steel fiber reinforced concrete based on DEM-SPH coupling

Abstract

The distribution morphology of steel fiber and coarse aggregate in fresh self-compacting steel fiber reinforced concrete (SFRC) during pouring significantly influences the dispersion and orientation of properties in the hardened concrete. Current numerical simulation methods face limitations in accurately characterizing the dynamic distribution of steel fibers and coarse aggregates during the pouring process of self-compacting SFRC. In this study, a meso-scale numerical model coupling the Discrete Element Method (DEM) and Smoothed Particle Hydrodynamics (SPH) is proposed to investigate the flow behavior of fresh self-compacting SFRC. DEM simulates the discrete particle behavior of steel fibers and coarse aggregates, while SPH captures the flow properties of the mortar matrix. The solid-liquid interactions are analyzed using a two-way fluid-solid coupling mechanism. The model is applied to simulate the pouring process of a self-compacting SFRC circular slab with the number of aggregates and fiber distribution in different regions quantitatively extracted from the results. For validation, a full-scale self-compacting SFRC slab is cast, and after hardening, the slab is cut using a water jet. The actual distribution of fibers and coarse aggregates is analyzed using an image analysis method. The simulation results, including the fiber dispersion coefficient, the main fiber orientation, and coarse aggregate distribution along the flow distance, align well with the experimental data. The numerical model demonstrates high reliability in predicting the flow behavior of self-compacting SFRC.