Numerical Evaluation on Buildability of 3D Printing Mortar Based on Time-Dependent Material Model (2025-10)¶

Buildability in material extrusion methods, often employed in cementbased 3D printing for construction, is influenced by printing conditions such as model geometry, time-dependent material properties, and printing speed. Consequently, selecting appropriate printing conditions that ensure sufficient buildability for practical 3D printing projects poses a challenge. This study aims to predict buildability through numerical analysis by considering printing conditions as input information. It primarily involved conducting piling-up experiments with the extrusion of 3D printing mortar and performing reproduction analyses under two distinct printing conditions. The finite element method was utilized for the analysis, incorporating an elastoplastic model into the material constitutive law. To accommodate the stiffening property of the 3D printing mortar at very early ages, a time-dependent model for Young’s modulus and cohesion was introduced. The outcomes of the piling-up experiments were classified into two failure modes: significant deformations occurring either at the bottom or the top part. Each failure mode corresponded closely with the respective numerical analysis. The strong concordance between the experimental and analytical collapse modes underscores the effectiveness of incorporating time-dependent material parameters into numerical modeling.