• Ball, Richard J.
• Dams, Barrie
• Chen, Binling
• Shepherd, Paul

Abstract

Additive manufacturing, better known as ‘3D printing’ is being increasingly investigated as a method of constructing buildings. Typically, deposition platforms involve large ground-based gantries or robotic arms. Aerial Additive manufacturing is the world’s first project to demonstrate the feasibility of multiple self-powered untethered drones extruding material in flight to construct multiple layers. Use of drones requires the miniaturisation of the additive manufacturing deposition process and the use of lightweight cementitious material. Material in the fresh state needs to exhibit pseudoplastic (shear thinning) behaviour. This involves the material possessing a reduced viscosity while under stress in the deposition system, which then increases by orders of magnitude once deposited thereby minimising deformation due to self-weight and the weight of subsequently deposited layers. Cellulose and xanthan gum were used as rheology modifying admixtures to promote pseudoplastic behaviour, with fly ash and <br/>smooth-particle sand used to aid workability. The addition of fibres can improve the flexural and compressive strengths and improve buildability but may decrease the workability of the mix. The addition of tungsten disulphide inorganic fullerene nanoparticles was demonstrated to improve mechanical properties and the impact resistance of 3D printed material. Aerial <br/>additive manufacturing could enable work in elevated or challenging site conditions and promote architectural freedom in design.<br/>

Topics

• nanoparticle
• Deposition
• impedance spectroscopy
• strength
• viscosity
• cellulose
• tungsten
• additive manufacturing