## 1 Introduction
The residual w/c ratio (which is independent of the initial mixture w/c ratio) will be between 0.30 and 0.32 [14; 15; 16] when the optimal centrifugation time and pressing pressure is reached. The strength of the concrete changes at different points throughout the thickness of the wall of the centrifuged element. A high resistance of concrete is found at the outer surface of the element, with the weakest in the inner surface [10; 11; 12]. This difference can be up to 20% for thin-walled (wall thickness up to 70 mm) centrifuged elements [13; 17; 18]. The anisotropy of the texture and density of concrete in the wall of centrifuged element changes the strength, deformability and other physical-mechanical properties [16]. Reinforcement can affect the conditions of compaction and curing of concrete, the values of shrinkage stresses, the occurrence of additional damage to concrete, the redistribution of stresses between concrete and reinforcement and the stress-strain state of the concrete inside the spiral [19]. There was much research during the 1950 s and 1970 s into the mechanical and technological properties of centrifuged concrete, at a time when increasing overhead powerlines were being erected throughout the world, which required a commensurate number of poles to support centrifuged power lines [3; 20; 21]. Nevertheless, evidence for the influence of longitudinal and transverse reinforcements on the mechanical properties of centrifuged concrete during production is mostly absent in scientific literature. Reinforcement is an important factor and does affect the mechanical properties of centrifuged concrete. In recent year's there was more research on the use of FRP reinforcement, as well as on vibrated concrete structures reinforced with longitudinal and transverse FRP reinforcement. Numerous articles [19; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31] have be published on the work of full circular cross section concentrically and eccentrically loaded concrete columns reinforced with FRP and GFRP and on the physical-mechanical properties of concrete. Our conclusions do not suggest an assessment of the influence of spiral reinforcement on the bearing capacity or deformability of annular cross section of centrifuged reinforced concrete structures. Various experimental studies provided new data on physical and mechanical properties of centrifuged concrete (i.e., strength, deformability and durability) under varying and maintenance conditions [18; 1; 32]. The results obtained in these studies allowed the researchers to define the applied theories to predict strength, toughness, reliability, durability and resistance to cracking of differently reinforced elements of annular cross section more exactly. With the introduction of a new generation of reinforcement (high-strength metal and FRP) and various additives that improve the properties of concrete mixture, the improvement of structural production technologies made it necessary to expand experimental research [1; 2]. The purpose of this study is to analyze the physical and mechanical properties of centrifuged concrete structures reinforced longitudinal and transverse reinforcement. The physical-mechanical properties of concrete in real structures may differ significantly from the control concrete samples. Physical-mechanical properties of centrifuged elements depend on composition of concrete, technology of their production, longitudinal and transverse reinforcement, wall thickness of elements. The presented and analyzed experimental research data provide some recommendation for engineers.