Bearing Capacity of Polymer-Composite Strengthened Bent Reinforced Concrete Elements under Conditions of Exposure to a Corrosive Environment

Abstract

The problem of ensuring the durability of reinforced concrete structures operating in aggressive environments remains extremely relevant. Corrosion of the reinforcement caused by exposure to chlorides leads to a significant decrease in load-bearing capacity and requires expensive repairs. A promising alternative to traditional methods of reinforcement with steel elements is the use of carbon fiber-based composite materials (CFRP), which have high strength and corrosion resistance. However, their durability under long-term exposure to aggressive environments has not been sufficiently studied. The purpose of this study was to experimentally evaluate the effectiveness of reinforcing bent reinforced concrete elements with carbon fiber and the effect of a chloride-containing environment on them. The methodology included testing a series of beams with different reinforcement schemes: without reinforcement, reinforced before corrosion, and reinforced after preliminary corrosion. An electrochemical method was used to accelerate corrosion. The results confirmed that rebar corrosion reduces the bearing capacity of the blocks by 50–60 %. The CFRP enhancement allowed it to be increased by 52 %, changing the nature of the fracture from a normal to an inclined section. The key conclusion is that the external composite reinforcement effectively protects the structure, however, repeated corrosion of the reinforced element causes an increase in internal stresses and the formation of cracks in concrete due to the accumulation of corrosion products. The study highlights the need to take these factors into account to ensure the durability of reinforced structures.