Evaluation of the Durability and Flexural Performance of BFRP-RC Beams in Aggressive Marine Environments

Basalt fiber–reinforced polymer (BFRP) reinforcing bars have become a viable substitute for conventional steel reinforcement in concrete structures, primarily due to their exceptional resistance to corrosion and light weight. These characteristics make BFRP bars particularly advantageous for applications in saline environments, such as marine infrastructure, where chloride exposure and harsh conditions accelerate the deterioration of steel reinforcement. This research focused on evaluating the durability and flexural performance of BFRP-reinforced concrete (BFRP-RC) beams preconditioned in simulated marine settings. A total of eight beams were tested: six beams incorporated BFRP bars conditioned in a 3.5% saline solution at 60°C for 3, 6, or 12 months before casting, while two unconditioned beams served as control specimens. The experimental findings show that the tensile strength retention of the sand-coated and ribbed BFRP bars after 12 months of conditioning was 91% and 89%, respectively. Full-scale beam testing revealed moment capacities ranging from 64 to 71 kN·m, with variations of less than 5% compared to control specimens. Crack widths at ultimate load remained nearly unchanged, increasing by only 0.04 mm for sand-coated bars and 0.03 mm for ribbed bars after 12 months. Additionally, long-term performance predictions using the Arrhenius model estimated the durability of the BFRP bars to exceed 100 years in tropical climates and 125 years in colder northern regions.