Multiphysics simulation of time-dependent early-age behaviourin 3D printed concrete

A lack of reliable predictive models for early-age behaviour is impeding the widespread adoption of 3D concrete printing (3DCP), a new construction technique that is gaining popularity. The layer-by-layer deposition method presents special difficulties regarding changing mechanical characteristics, heat effects, and moisture loss. In this work, the time-dependent response of printed concrete is simulated using a Multiphysics Finite Element Model (MFEM) framework. By connecting the development of shrinkage and strains with the progression of hydration, the model integrates mechanical behaviour with hygro-thermal-chemical (HTC) analysis. This model that has been calibrated against published calorimetry data is used to capture the kinetics of hydration. Eigenstrains are used to model important early-age processes, such as drying shrinkage, autogenous shrinkage and total shrinkage. The framework facilitates process parameter optimisation and provides predictive insights into early-age behaviour. Experimental validation and extension to long-term durability modelling will be part of future research.