Early Age Creep Behavior of 3D Printable Mortar (2025-09)¶

Early age creep significantly influences buildability in extrusion-based 3D concrete printing(3DCP). This time-dependent deformation is primarily governed by the evolution of mechanical properties resulting from early-stage cement hydration. However, the role of hydration-induced aging in early age creep has received limited attention in prior research. In this study, a hydration model based on water diffusion in the alite (C3S) phase was employed to predict the evolution of the degree of hydration up to the dormant period. This evolution was then coupled with Burger’s viscoelastic model parameters using a simplified power-law relationship to account for aging effects. A finite element-based numerical framework was developed to simulate the early-age creep behavior of printable mortar using this hydration–viscoelastic coupled model. The proposed model’s capability was demonstrated using three printable mortar mixes reported in the literature, highlighting its effectiveness in capturing the time-dependent response during the early stages of the 3D printing process. Furthermore, a local sensitivity analysis was performed to identify the most influential model parameter governing the model’s predictive performance.