Computational Algorithms for Early-Age Creep and Buildability Prediction in Extrusion-Based 3D Concrete Printing: A Critical Survey

Abstract

Early-age deformation is a major limitation on the buildability of extrusion-based 3D-printed concrete because each deposited layer must carry increasing self-weight while hydration, thixotropic rebuilding, stiffness, and strength are still evolving. This survey reviews experimental, rheological, analytical, and numerical approaches used to characterize and predict creep and related deformation during printing. The reviewed experiments include compression, creep-recovery, digital image correlation, and full-scale printing tests. Analytical approaches include Burgers, generalized Kelvin, power-law, and hydration-coupled viscoelastic formulations, whereas numerical studies employ continuum finite elements, lattice and voxel activation, damage-rheology laws, particle finite elements, computational fluid dynamics, and coupled fluid-solid models. Across these approaches, predicted buildability depends strongly on material age at loading, load duration, deposition interval, layer geometry, and interface behavior. The literature shows that elastic models are useful for rapid screening, but viscoelastic, plastic, or damage mechanisms become important when printing duration is long or stress approaches the evolving resistance. Remaining priorities are standardized early-age tests, independent validation, uncertainty quantification, and transferable models that connect material characterization with layer-by-layer structural analysis.