A review of “3D concrete printing”: Materials and process characterization, economic considerations and environmental sustainability

3D printing of cementitious materials or concrete (3DCP) has developed unbelievably in past 10 years and has the potential to revolutionize the concrete industry completely in the couple of incoming decades. Compared to cast concrete, 3DCP technology has a high customizability of architectural and structural design; can reduce material consumption, minimize material waste, decrease construction time from months or days to hours; can improve sustainability, environmental impact and resolve residential crises through providing $10,000 homes. In this article, a comprehensive review for 3D printing of various materials, techniques and trending applications has been carried out. The materials used for 3DCP, mix design principles and printing process parameters has been overviewed. The factors influencing flowability, extrudability, buildability of various mixes; microstructure and mechanical properties of the hardened concrete; and improvement techniques has been discussed. An important part of this review is provided to highlight the cost of 3D printed houses compared with traditional alternatives, and environmental sustainability of 3DCP and its compatibility with international plans for climate change and minimizing the energy usage. Finally, some to-date challenges are discussed, with conclusions that also identifies the needed research and state of the art for this incredible technology. Overall, this review presents the finding of the mentioned topics through exploring 396 of the latest published articles especially focusing on last three years.