Nonlinear Predictive Modeling of Building Rates Incorporating Filament Compression Deformations in 3D Printed Geopolymer Concrete (2025-03)¶

3D printed concrete undergoes compressive deformation when printed fresh, often overlooked by traditional methods, impacting buildability prediction accuracy. In this paper, the buildability prediction model is modified by incorporating the Mohr–Coulomb damage criterion and focusing on the compressive deformation during the printing process. The prediction model combines the following key components: 1) the utilization of bilinear stress–time loading curves to simulate nonlinear stress–time loading curves during the actual printing process; 2) conducting uniaxial unconfined compression tests on cylindrical fresh specimens with different aspect ratios (ranging from 0.25 to 2) to extract the stress–strain response of the material; 3) the refinement of material parameters (including elastic modulus and plastic yield stress) and their variations with aspect ratio derived from the uniaxial unconfined tests. The material experimentation results indicate that the green strength exponentially decreases with increasing aspect ratio, while Young’s modulus exhibits a linear increase with the same parameter. Experimental comparisons were made during hollow drum printing tests using two different printing materials against the Mohr–Coulomb buildability prediction model. The results from these experiments demonstrate the improved accuracy of the new model in predicting failure heights (with relative error rates of 5.4% and 10.5%).