Characterisation and Modelling of a 3D Concrete Printed Wall under Flexure (2022-06)¶

The use of 3D concrete printing (3DCP) opens a wide range of new and revolutionary possibilities in the construction industry. However, the development of materials and the manufacturing of structural elements face several challenges that need to be addressed to produce safe and reliable 3DCP structures. Accordingly, and given the layer-to-layer based 3DCP manufacturing method, further research is required to identify the properties of the internal structure of the material and its influence on the structural performance. This study aims at analysing the performance of a 3DCP material through an experimental programme involving the characterisation of a 3DCP material and the analysis of the behaviour under flexure of a 3DCP wall manufactured using the Contour Crafting procedure. For this, concrete beams were printed to extract cores and determine the mechanical properties of concrete, while analysing the anisotropy of the material in different directions. Additionally, a wall with dimensions 2.70x1.20x0.30 m was produced and tested under a three-point bending configuration. The mechanical characterisation of 3DCP cores revealed an anisotropic behaviour of the material in the different testing directions due to the layer-based structure of the printing procedure. The results of the 3DCP wall tested under flexure exhibited a failure in different stages as a result of the presence of irregularities introduced by the printing manufacturing method. Consequently, both the anisotropy and the irregularities of the structural elements need to be taken into account at the design stage given its significant impact on the strength and the influence on the structural behaviour. These results provide valuable information about the behaviour of concrete printed materials and show the necessity of developing design specifications beyond those currently in use for traditional poured concrete.