Estudo da aderência entre barras de PRFV e o concreto

Abstract

Reinforced concrete is widely used in the world, and in Brazil it is the most used construction method. However, the carbon steel of the reinforced concrete structure can be subject to corrosion, which leads to the search for new materials to replace carbon steel as reinforcement. In this sense, fiberglass-reinforced polymer bars (FRP) appear. These composite materials are capable of acting in aggressive media, have a good strength-to-weight ratio, in addition to good fatigue behavior. With the increase in their use, there is a need for further studies on the properties of these bars. For example, the study of adhesion is essential to understand the mechanical behavior and performance of reinforced concrete structures. In this sense, this work aims to study the adhesion between FRP bars and concrete, through pullout tests, in accordance with the ASTM D7913/D7913M-14 (2020) standard, with FRPV bars of 8 mm, 10 mm and 12 mm in diameter, inserted in concrete cubes with characteristic strengths of 25 MPa and 35 MPa, in order to compare the effects of bar diameter and characteristic strength of concrete on bond strength. Data obtained experimentally were compared with equations found in the Canadian CSA S806-02 (2002), Brazilian CT 303 (2021) and American ACI 440.1 R-15 (2015) standards. The results obtained show statistically similar bond strength between the FRP bars and the concrete, even with the increase in the diameter of the bars, regardless of the compressive strength of the concrete. Another evaluated factor is the resistance of the concrete, the results indicate that there is a tendency in the increase of the adhesion resistance with the increase of the compressive strength of the concrete, however this increase was only significant in this study, for the bars of 12 mm. It is therefore concluded that, according to the results obtained in this study, with the increase in the compressive strength of the concrete, there is an increase in the adhesion stress for 12 mm bars, in contrast, the change in the diameter of the FRP bars, does not significantly change the bond strength of the structure. Keywords: GFRP bars; pullout test; bond strength.