3D printing (or ‘additive manufacturing’ (AM)) systems used to manufacture cementitious structures, either in-situ or off site, utilise specialist formulations. This paper describes a new cementitious formulation which can be extruded from a syringe device without the requirement for the addition of an accelerator at the nozzle. This miniature approach brings advantages in that the system required is smaller, lighter, consumes less power and is suitable for mounting on robots which are not reliant on external power or material supplies. Applications of this smaller scale system include concrete crack repair in hard to access areas and printing of specialist conductive formulations which can be used for sensing. Cementitious pastes were successfully printed using a miniature deposition device which could be carried by a small robotic printing agent. Appropriate workability and buildability following deposition was achieved through the use of cellulose gum additions to the mix formulation. Analysis and characterisation tests carried out on fresh mixes enabled comparison of a 1:1 mix of aluminium lactate and diethanolamine with the commercially available accelerator Master X-Seed, and mixes with no accelerating admixture added. When compared to results featuring no accelerating agent, tests demonstrated that Master X-Seed was the more effective accelerator, promoting early compressive and flexural strength development, but neither accelerator made a constructive contribution to required rheological properties. Master X-Seed was the more effective accelerator, but rheology results suggest the difference occurs logistically too soon for a miniaturised deposition system. The retardation effect of cellulose gum and the potential role of in-situ and off-site miniaturised AM methods are evaluated.
|Number of pages||65|
|Publication status||Published - 20 Apr 2021|
|Event||2nd International Conference on Construction Materials for Sustainable Future - Bled, Slovenia|
Duration: 20 Apr 2021 → 21 Apr 2021
|Conference||2nd International Conference on Construction Materials for Sustainable Future|
|Period||20/04/21 → 21/04/21|