Rheological and Strength-Characterisation of Limestone-Calcined-Clay-Cement 3D Printed Concrete (2022-09)¶

The advancement in modern-day construction has paved the way for the development of a new technology named 3D concrete printing. This technology offers the following merits over conventional cast concrete: improved quality with much less construction cost and wastes, production of high load carrying capacity, and high resistance to environmental hazards. Also, the use of limestone calcined clay cement (LC3)for civil and construction engineering applications has gained a progressing interest in recent years due to its exceptional chemical and microstructural properties, and reduction in cement content and mitigating the emission of greenhouse gas. This paper presents the rheological and mechanical characterisation of polypropylene fibre-reinforced 3D printed concrete (3DPC) containing LC3. The material mix design satisfying 3DPC requirements for early strength and stiffness, shrinkage cracking resistance and mechanical properties, including interfacial bond, was developed. The physical properties and the particle size distribution of the binders (cement and limestone calcined clay; LC2) and aggregate in compliance with Fuller-Thompson’s ideal curve/theory produced a high-performance concrete mix without compromising the rheological design approach for 3DPC. Finally, the high performance is demonstrated by the buildability and shape retention of the 3DPC results in the fresh state, and the characterised hardened mechanical test results of the printed and cast samples.