Citation: Wang, Y.; Aslani, F.; Dyskin, A.; Pasternak, E. Digital Twin Applications in 3D Concrete Printing. Sustainability 2023, 15, 2124. https:// doi.org/10.3390/su15032124 Academic Editors: Sandra Pereira and Sayanthan Ramakrishnan Received: 23 November 2022 Revised: 5 January 2023 Accepted: 17 January 2023 Published: 23 January 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Review Digital Twin Applications in 3D Concrete Printing Yuxin Wang 1 , Farhad Aslani 1,2,3, * , Arcady Dyskin 1,2 and Elena Pasternak 1,2 1 School of Engineering, University of Western Australia, Perth, WA 6009, Australia 2 UWA International Space Centre, University of Western Australia, Perth, WA 6009, Australia 3 School of Engineering, Edith Cowan University, Perth, WA 6027, Australia * Correspondence: farhad.aslani@uwa.edu.au Abstract: The benefits of 3D concrete printing (3DCP) include reducing construction time and costs, providing design freedom, and being environmentally friendly. This technology is expected to be effective in addressing the global house shortage. This review highlights the main 3DCP applications and four critical challenges. It is proposed to combine 3D concrete printing with Digital Twin (DT) technology to meet the challenges the 3DCP faces and improve quality and sustainability. This paper provides a critical review of research into the application of DT technology in 3DCP, categorize the applications and directions proposed according to different lifecycles, and explore the possibility of incorporating them into existing 3DCP systems. A comprehensive roadmap was proposed to detail how DT can be used at different lifecycle stages to optimize and address the four main challenges of 3DCP, providing directions and ideas for further research. Keywords: 3D printing; 3DCP; digital twin; construction industry 1. Introduction Global housing shortage, the effects of global climate change, and rising labor costs due to a shortage of skilled workers are driving the construction industry to question traditional construction methods and push the limits of innovation. In this quest, additive manufacturing (AM) technology (in particular 3D concrete printing) is gaining ground in the construction industry to respond to the urgent demand for acceleration and mechaniza- tion [1]. The method of automating construction by reading digital models of buildings will undoubtedly blaze a new path for the construction industry to achieve cost reduction [2], environmental protection [3], and realize complex shaped designs [4]. Additive manufac- turing, such as 3D concrete printing, is well suited for adopting digital technologies and achieving automating construction. The method of 3D concrete printing is also suitable for creating structural elements with complex geometries, which allows building structures of non-traditional architecture [5]. In addition, this technology can significantly improve sus- tainability and reduce energy consumption, with reduced construction time and waste [6], and use short fiber reinforced filaments from recycled plastics and fibers (such as polypropy- lene and basalt) as a printing material [7]. Despite existing beliefs that 3D printing is a difficult alternative to traditional construction methods, there are cases when 3D printing can provide an extremely effective solution [5]. In addition to its ability to create complex shapes, it can also be effective in response to disasters [4]. Whenever a natural disaster such as a hurricane or earthquake destroys infrastructure and leaves people homeless, 3D concrete printing can be used to quickly rebuild bridges, roads, and houses. Finally, based on its low cost and high efficiency, it can be a practical option for social housing projects [8]. The past few years have seen a proliferation of 3D-printed buildings, including administrative buildings in Dubai, residential houses in various European countries [9], and apartments and bridges in China [10]. The method of 3D printing even underpins NASA’s proposals for a Mars habitat [4]. This shows that this new technology, which Sustainability 2023, 15, 2124. https://doi.org/10.3390/su15032124 https://www.mdpi.com/journal/sustainability