Discrete Fresh Concrete Model for Simulation of Ordinary, Self-Consolidating, and Printable Concrete Flow

This paper deals with the formulation and validation of the discrete fresh concrete (DFC) model to simulate the rheological behavior of self-consolidating, ordinary, and printable concrete in the fluid state immediately after mixing. The DFC model is formulated within the framework of the discrete-element method (DEM), and it models the interaction among coarse aggregate particles embedded in a fine mortar. The formulation is based on stress-strain constitutive equations through which the behavior of fresh concrete can be described by parameters with clear physical meaning. This study presents a rigorous methodology for estimating the model key input parameters by the comparison of numerical simulations with experimental data. This methodology includes (1) a series of sensitivity analyses and simulations to establish the relationship between constitutive parameters and macroscopic properties; and (2) numerical simulations of experimental tests commonly used to characterize the fresh state behavior of concrete. Finally, the paper discusses the application of the DFC model to the simulation of concrete additive manufacturing.