Mechanical Properties of a 3D Printed Wall Segment Made with an Earthen Mixture
This paper is part of the research on 3D printing of earthen housing modules, made with earth taken in situ. Previous studies have already led to the definition of 3D printed earthen elements for the external cladding of single-story wooden load-bearing structures. With this work, we intend to take a step forward in the use of 3D printed earthen elements, studying their load-bearing capacity for vertical loads. The goal is to create load-bearing structures entirely in earth, with two or more floors. To this end, the present work investigates two of the major presumed criticalities of 3D printed elements under vertical load, namely the detachments due to poor cohesion between extruded layers and the detachments between internal infill and external coating. The uniaxial compression test on a specially 3D printed wall segment did not actually show any particular danger for the stability of the structure, due to detachment phenomena. Rather, the experimental results showed some quite anomalous mechanical behaviors for a brittle construction material (studied at the mesoscale), especially as regards Poisson’s modulus and volumetric strain. The main experimental finding concerns the contribution of the internal infill, which seems to have a structural function and not just a filling function.