Bond strength durability of BFRP bars in concrete subjected to elevated temperature and alkaline environment

Abstract

The use of basalt fiber–reinforced polymer (BFRP) bars as a reinforcing material for concrete structures has gained increasing interest worldwide. Limited studies have been reported on the performance of BFRP bars in concrete when exposed to harsh environments. This paper presents the test results of an experimental study aimed at investigating the bond strength durability of BFRP bars embedded in concrete when exposed to accelerated environmental effects. The experimental program included testing and investigating BFRP deformed bars with 12-mm diameter. Pullout specimens were tested under direct tensile load after being exposed to an alkaline solution (pH=12.9) for up to 6 months at elevated temperatures of 40 o C. Effects of alkali environment and exposure periods on the bond strength, degradation mechanism, and mode of failure of reinforced specimens with BFRP were investigated. The test results revealed that the average bond strength of conditioned specimens after 1.5, 3, and 6 months of exposure at 40o C were 14.8, 13.3, and 12.5 MPa, while the bond strength of unconditioned specimens was 15.5 MPa. Accelerated alkaline environments had a harmful effect on bond strength of conditioned specimens over time. After 6 months of exposure, the bond strength retention was 81% compared to that of the unconditioned specimens