Characterising Concrete Mixes for 3D Printing

Abstract

The construction industry is currently experiencing significant change as building information modeling (BIM), digital design and construction automation are exerting intense pressure on traditional technologies. As an advanced manufacturing technology, three-dimensional (3D) printing has significant potential applications in the construction sector, by utilizing a programmable robotic arm with a nozzle jet, 3D printing can enable us to construct complex concrete structures layer by layer. This new construction technique offers an advanced approach that can potentially accelerate the construction time and improve efficiency. They can work 24/7, even in a hazardous environment while minimising human errors. However, as an advanced cutting-edge technology, there are several remaining challenges to be overcome in comparison to traditional concrete casting, and these include appropriate pumpability, extrudability, buildability, compressive strength and open time for printing concrete. To overcome these challenges this project will investigate the effect of nanoclay to improve the fresh properties of printing concrete. It is considered that by utilizing different amounts of nanoclay and superplasticiser in the mix it will be possible to significantly affect the fresh properties of 3D printed concrete. Printable materials, like any other cementitious materials, flow only when submitted to stresses higher than a critical yield stress. In this project, a shear vane test was used to measure the yield stress of cement-based materials in the lab.