Today, the development and research of new designs requires a systematic approach, including design, manufacture of products and construction. Further development of construction follows the path of improving the designs and forms of buildings, which is facilitated by the improvement of the physical and mechanical properties of building materials. The use of high-strength concrete and steel leads to the creation of lighter thin-walled reinforced concrete structures and is fundamentally possible only with perfect technology for the manufacture of elements. Since in the manufacture of reinforced concrete products by a centrifugal method, radially directed filtration channels are formed, it is in them that the manifestation of destruction is most likely. It is aggravated by the fact that the inner layer of such products is more porous than other layers of concrete. The presence of such a structure is determined even if all the requirements for the quality of the raw materials, the preparation of the concrete mix and the use of optimal centrifugation modes are met. The authors in the process of confirming the working hypothesis in this study developed a method of introducing aggregate during centrifugation, on the basis of which prototypes were obtained, which are characterized, compared with the control, improved physicomechanical and structural properties; an increase in the carrying capacity of centrifuged reinforced concrete columns of annular cross section was achieved at the stage of their manufacture by changing the nature of the manufacturing process from one stage to two stages. Testing the hypothesis was carried out by the determined increments of the structural and physical characteristics of the concrete samples. The density of concrete prototypes of centrifuged reinforced concrete columns of annular section of two-stage molding with all three ratios of fractions was higher than that of single-stage concrete. Water absorption at concrete capillary suction of prototypes of centrifuged reinforced concrete columns of annular section of two-stage molding with all three fractions ratios was lower than that of single-stage concrete.

Keywords: centrifuged concrete, reinforced concrete columns, aggregate fractions, two-stage technology, annular section, density, water absorption, structural and physical properties