Abstract
dimensional concrete printing (3DCP) has emerged as a transformative technique, with a potential to revolutionize concrete construction. The technology offers many advantages compared to the traditional way of construction. A pivotal aspect of achieving success in 3D concrete printing lies in the optimisation of the concrete or mortar mix. Most proposed 3D concrete mixtures contain larger quantities of Portland cement which counters the benefits of 3D concrete printing. Although previous studies suggested use of limestone calcined clay cement (LC3) in 3D concrete printing, limited studies have addressed the optimisation of LC3 concrete mixtures for 3D printing. A trial-and-error method is currently being used to guide the mix design of 3D concrete printing. Therefore, this research focuses on the optimisation of limestone calcined clay concrete mixtures specifically for 3D concrete printing.
The study investigated the fresh and hardened properties of 3D concrete mixtues. LC3 was used as a partial replacement for the Ordinary Portland Cement and the impact of this replacement were investigated. The research employed a multiple rigorous testing methods such as flow table tests, vicat needle and trial prints to determine fresh properties such as extrudability, buildability, open time and workability. The finding showed that an optimum mix consisted of 55 % replacement of Portland cement (PC) with LC3, 0.5 water to binder ratio, 2% superplastisizer content. The sand to binder ratio of 1.5:1 was used and a ratio for limestone to calcined clay was 1:2. Flowability and open time of the concrete mixtures reduced with an increase in the content of limestone and calcined clay. Increasing LC3 content reduced the extrudability of the material while improving the buildability. The compressive and flexural strength of decreased notably with increasing LC3 content.
This comprehensive investigation aims to unlock the potential of limestone-calcined clay-based cementitious materials for 3DCP, offering a sustainable alternative with a focus on mitigating the environmental impact associated with traditional PC-dominated mix designs. The findings from this study contribute not only to the advancement of 3D concrete printing but also to the broader discourse on sustainable construction practices.
Keywords: Limestone Calcined Clay Cement (LC3), Three dimensional concrete printing (3DCP), Flowability, Extrudability, Buildability.