Simulation of Concrete DEF Expansion Under Restraint Using 3D RBSM

Delayed ettringite formation (DEF) is a durability issue that can cause concrete expansion and cracking. While significant efforts have been made to investigate the microscopic mechanisms of DEF expansion, relatively few studies have focused on structural models. Understanding the effect of stress on DEF expansion is crucial for evaluating the performance of structures affected by this phenomenon. Although experiments are useful for studying structural performance under certain conditions, visualizing the internal state of concrete and reinforcement through experiments is challenging. Therefore, numerical simulation is generally a more effective method for making such predictions. In this study, the discrete numerical analysis method, 3D Rigid Body Spring Model (RBSM), is used to simulate concrete DEF expansion under external restraint. The simulation is based on one experiment, and it discusses the macroscopic expansion and anisotropic expansion behavior due to restraint. Both the surface cracking pattern and the internal crack development are visualized through the simulation. The reasonableness of the simulation results and the limitations of RBSM in simulating DEF under restraint conditions are discussed in this paper, which enables further study of DEF damage at the structural level using this simulation method.