RESEARCH OF DEFORMATION AND STRENGTH CHARACTERISTICS OF CONCRETE COLUMNS WITH COMPOSITE REINFORCEMENT

The article presents the results of experimental studies on the load-bearing capacity of concrete specimens reinforced with a fiberglass shell under axial loading. Cylindrical concrete specimens were reinforced with strip fiberglass reinforcement (SFRP) using a developed winding technology and layer-by-layer bonding with a polymer binder. The main focus is on studying the influence of lateral pressure, created by the fiberglass shell, on the strength and deformation characteristics of concrete. The experiments demonstrated that the use of a fiberglass shell significantly increases the failure load. For concrete of class C16/20, the failure load increased from 100 kN (without the shell) to 980 kN (with a 4 mm thick shell), which is 9.8 times higher. A similar increase in strength was observed for concretes of other classes (C25/30, C32/40, C50), with the failure load for C50 concrete increasing by a factor of 5.2. It has been established that the intensity of strength gain depends on the concrete class; however, at high levels of lateral pressure (above 80 MPa), the strengthening coefficient (α) becomes nearly identical for all concrete classes (α ≈ 1.85). This indicates the similarity of concrete behavior in a fiberglass jacket to its behavior in steel jackets, with the added advantage of fiberglass’s high corrosion resistance. The deformation characteristics of the specimens were also studied. It was shown that the fiberglass jacket not only enhances strength but also improves the deformation properties of concrete, making it more resistant to longitudinal and transverse deformations. The obtained results confirm that glass fiber-reinforced concrete can be considered a promising structural material for the construction of highly loaded structures. The developed technology for strengthening concrete with a fiberglass jacket opens new possibilities for creating lightweight, durable, and long-lasting structures with low metal consumption and high corrosion resistance.