ANALYSIS OF EXISTING TECHNOLOGICAL SOLUTIONS OF 3D-PRINTING IN CONSTRUCTION

The paper discusses the international experience of 3D-printing technology implementation in construction. The analysis of existing technological solutions of domestic and foreign organizations such as WinSun, AMT-SPETSAVIA, StroyBot, BetAbram, Contour Crafting Corp., ApisCor, Loughborough University, CyBe Construction, Batiprint3D, MIT Media Lab and DUS Architects is performed. The advantages and disadvantages of different approaches to performing layer-by-layer construction of building structures are shown. Subject: the analysis of products and structures made of cement concretes produced by the layer-by-layer extrusion method is carried out in this paper. Materials and methods: in this work we use a complex of general scientific logical methods of research based on a theoretical analysis of technological solutions presented in the scientific and technical literature, information resources from developers and the media recourses, including patents, scientific articles and scientific reports. Results: the existing technological solutions of 3D-printing in construction are analyzed, their advantages and disadvantages are shown, and the problems of technology development are formulated. It is established that the main material for 3D-printing is the cement heavyweight fine-grained concrete, which includes a filler of size no more than 4 mm, mineral additives, microfiber, anti-shrinkage chemical additives and setting time regulators. The concrete has an average density of 2100...2200 kg/m3 and a compressive strength of 25...50 MPa. It was found that the non-optimal rheological properties of mixtures and the absence of solutions to improve the operational properties of concrete do not allow us to expand the functionality of printed elements beyond enclosing structures or permanent formwork and fully realize the potential of 3D printing. Conclusions: the process of extrusion for building construction must be based on general principles and requirements to materials and structures. The search of the complex technological solutions on the each stage of construction is a promising task for the development of 3D-printing in construction. It is necessary to formulate general requirements to materials used in concrete 3D-printing and develop universal prescription solutions that allow us to simultaneously control the viscosity and flow of the mixture during extrusion and also create the required physical, mechanical and operational properties. Key words: 3D-technology, 3D-printing, contour construction, rapid prototyping, materials for 3D-printing, extrusion, layer-by-layer design construction, 3D-printer, mixture for 3D-printing, building ink, high-strength concretes, dry building mixtures Acknowledgements: The work was carried out within the framework of the agreement No. 14.583.21.0072 on granting awards for implementation of the federal target program “Research and development in priority directions of development of the scientific and technological complex of Russia for 2014-2020” (project identifier RFMEFI58318X0072) with the financial support from the Ministry of Education and Science of the Russian Federation.