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the paper considers the problem of creating a wider class of building materials used for 3D printing. From the point of view of classical rheology of disperse systems, the application of 3D printing technology in construction has been analyzed. theoretical analysis of the models of rheological behavior is performed according to state of their structure and the dynamic of the 3D printing processes such as mixing, pumping, extrusion, multilayer casting and structural built-up in the printing layers. the main factors and criteria for the stability of heterogeneous disperse systems in dynamic and static 3D printing processes have been identified. the general scientific concept for optimization of admixtures for 3D printable materials has been developed in terms of viscosity, consistency, and parameters of flocculation and structural built-up. the technological tools to control rheological behavior of visco-plastic admixtures are identified in all stages of 3D printing. the relevant considerations include the concentration, size, morphology, chemical and mineralogical composition, the physical and chemical activity of the solid phase's surface, and the ionic composition, viscosity, and density of the liquid phase. It is shown that the practical engineering solutions to control the rheology, structure formation, properties of 3D printing admixtures and materials must be based on traditional factors as well as with the use of «nano» tools. According to the nanotechnological principle «bottom-up», a set of http://nanobuild.ru

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The issues related to the feasibility study of the effectiveness of the use of 3D printing technology in residential construction are considered. The criteria for efficiency are indicated such as minimum human labor and minimum direct costs per m2 of the total area of a residential facility. It is noted that direct costs include the cost of materials, human labor, the operation of machinery. In the process of calculating performance indicators, the greatest difficulty arises with determining the cost of 3D printer, the value of which depends on the annual fund of the printer operation time, its performance and the cost of operation machine-hour. The cost of a machine-hour contains the cost of depreciation, human labor costs, the replacement of high-wear parts and units of machines, for energy, maintenance, relocation and installation of machines on the construction site. For each of the indicated cost elements, methodical approaches are proposed and corresponding calculation schemes are presented. From the data obtained as a calculation result, it follows that to the greatest extent, the cost of operating machines per m3 of concrete mix, depends on the printer’s performance, and in the cost structure of a machine-hour the depreciation costs comprise the maximum share determined as a percentage of the cost of the unit. In this regard, as one of the strategic directions of expanding the use of 3D-additive construction technologies, the cost reduction of modern printers is indicated.

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