A theoretical model to predict the structural buildability of 3D printable concrete

Abstract

Three-dimensional concrete printing is a transformative technology ushering in revolutionary architectural design and construction automation changes. With recent advancements of this technology, a notable absence of theoretical models predicting structural buildability is required. This investigation aims to bridge this knowledge gap by introducing an innovative theoretical model for estimating the total number of layers printed by a concrete 3D printer. This proposed model considers material behavior, building rate, and failure criteria. The material properties are depicted by modeling structural buildability in two cases, (i) bilinear and (ii) exponential. The buildability is characterized by three subcases, namely (i) constant, (ii) increasing, and (iii) decreasing building rates. These subcases hinge on printing velocity, treated as a function of time. Furthermore, the failure modes of 3D printable concrete structures are delineated based on (i) the Mohr–Coulomb theory and (ii) elastic and plastic failure criteria. Additionally, a strength-correction factor is employed to consider the confinement effect of the printed layer. The ultimate expression of the proposed model embodies an exponential approach to gauging the structural buildability of the printed structures. The study encompasses model validation and extensive parametric analysis to scrutinize the impact of printing velocity, structuration rate, printing path, density, and yield stress.