EFFECT OF CORROSIVE ENVIRONMENT ON BOND STRENGTH OF FRP BARS IN DIFFERENT GRADE OF CONCRETE

Abstract: Corrosion of steel reinforcement severely compromises the longevity of concrete infrastructure in aggressive environments. Fiber-Reinforced Polymer (FRP) bars offer a corrosion-resistant alternative; however, maintaining exceptional bond integrity at the bar–concrete interface is critical for overall structural stability. This study systematically evaluates the impact of aggressive environmental conditioning on the compressive and bond strength of FRP bars embedded across three ordinary concrete grades: M30, M35, and M40. Pull-out specimens and cubes were subjected to accelerated curing in marine (3.5% NaCl) and industrial acidic (3.5% HCl) solutions for up to 28 days. Destructive testing revealed that acidic exposure inflicted the most severe deterioration, reducing bond strength by up to 30% and causing high susceptibility in lower-grade (M30) mixes. Conversely, higher-grade concrete (M40) demonstrated superior mechanical resilience due to its dense microstructural matrix, which effectively limited degradation, preserved critical confinement pressure, and ensured long-term interfacial load transfer efficiency.

Keywords: FRP bars, Bond strength, Corrosive environment, Concrete grade, Pull-out test, Compressive strength, Durability, Marine exposure, Acidic degradation, Structural performance.