FLEXURAL PERFORMANCE AND DESIGN EVALUATION OF REINFORCED CONCRETE BEAMS WITH STEEL REINFORCEMENT AND BASALT FIBER-REINFORCED POLYMER LONGITUDINAL BARS
Flexural Performance of Concrete Beams Reinforced with BFRP and Steel Bars
Abstract
This study experimentally and analytically investigates the flexural behaviour of RC beams reinforced with either conventional steel longitudinal bars or basalt fibre-reinforced polymer (BFRP) longitudinal bars in combination with steel stirrups. Eight simply supported beam specimens were tested under monotonic static loading, comprising two distinct reinforcement systems: steel-reinforced control beams and BFRP-reinforced beams. The experimental program evaluated reinforcement and concrete strains, mid-span deflections, cracking behaviour, ultimate load capacity, and elastic energy storage prior to failure. The results indicate that steel-reinforced beams exhibited ductile flexural failure characterized by steel yielding followed by gradual concrete crushing, enabling controlled crack development and deformation. In contrast, beams reinforced with BFRP longitudinal bars failed in a more brittle manner governed by concrete crushing, reflecting the linear-elastic response of BFRP reinforcement, while exhibiting larger deflections and higher concrete strain levels. Despite these differences in failure mode and ductility, BFRP-reinforced beams achieved comparable or higher ultimate load capacities relative to their steel-reinforced counterparts. Analytical predictions based on ACI 440.2R-08 showed good agreement with experimental results, with conservative underestimations of ultimate capacity (ACI/Exp ratios ranging from 0.93 to 0.97), confirming the reliability of current design provisions. The findings highlight the inherent trade-offs between stiffness, ductility, and load-carrying capacity associated with steel and BFRP reinforcement systems and emphasize the importance of serviceability considerations in BFRP-reinforced RC beam design.
References
Alabtah, F. G., Mahdi, E., & Eliyan, F. F. (2021). The use of fiber reinforced polymeric composites in pipelines: A review. Composite Structures, 276, 114595. https://doi.org/10.1016/j.compstruct.2021.114595.
Obaydullah, M. (2021). Strengthening of Prestressed Concrete Beams Using Combined Externally Bonded and Prestressed near Surface Mounted Technique (Doctoral dissertation, University of Malaya (Malaysia)). https://doi.org/10.3390/polym8070261
Effiong, J. U., & Ede, A. N. (2022). Experimental investigation on the strengthening of reinforced concrete beams using externally bonded and near-surface mounted natural fibre reinforced polymer composites-a review. Materials, 15(17), 5848. https://doi.org/10.3390/ma15175848
Megahed, F. A., Seleem, M. H., Badawy, A. A. M., & Sharaky, I. A. (2023). The flexural response of RC beams strengthened by EB/NSM techniques using FRP and metal materials: a state-of-the-art review. Innovative Infrastructure Solutions, 8(11), 289. https://shorturl.at/zTEuT.
Kumar, A., Dixit, S., Singh, S., S., Sreenivasa, S., Bains, P. S., & Sharma, R. (2025). Recent developments in the mechanical properties and recycling of fiber‐reinforced polymer composites. Polymer Composites, 46(5), 3883-3908.https://doi.org/10.1002/pc.29261
Jagadeesh, P., Rangappa, S. M., & Siengchin, S. (2024). Basalt fibers: An environmentally acceptable and sustainable green material for polymer composites. Construction and Building Materials, 436, 136834. https://doi.org/10.1016/j.conbuildmat.2024.136834.
Abdulhameed, S. S., & Hamza, D. M. (2023). Flexural behavior of reinforced concrete beams strengthened with hybrid steel-FRP reinforcements by using near surface mounted technique. Journal of Applied Engineering Science, 21(3), 758-766. https://doi.org/10.5937/jaes0-39645
Abulqasim, S. A., Noori, A. Q. N., & Celik, T. (2022). Numerical investigation on flexural behavior of RC beams with large web opening externally strengthened with CFRP laminates under cyclic load: Three-point bending test. Journal of Applied Engineering Science, 20(2), 571-581. https://doi.org/10.5937/jaes0-32985.
Mensah, C., Wang, Z., Bonsu, A. O., & Liang, W. (2020). Effect of different bond parameters on the mechanical properties of FRP and concrete interface. Polymers, 12(11), 2466. https://doi.org/10.3390/polym12112466
Barris, C., Baena, M., Jahani, Y., Codina, A., & Torres, L. (2023). Experimental study on flexural cracking and deformation of reinforced-concrete beams strengthened with NSM FRP reinforcement. Journal of Composites for Construction, 27(2), 04023006. https://doi.org/10.1061/JCCOF2.CCENG-390
Abushanab, A., Alnahhal, W., & Farraj, M. (2022). Experimental and finite element studies on the structural behavior of BFRC continuous beams reinforced with BFRP bars. Composite Structures, 281, 114982. https://doi.org/10.1016/j.compstruct.2021.114982
Alhoubi, Yazan, Zin Mahaini and Farid Abed. "The flexural performance of BFRP-reinforced UHPC beams compared to steel and GFRP-reinforced beams." Sustainability 14.22 (2022): 15139. https://doi.org/10.3390/su142215139
Alkhraisha, H., Mhanna, H., Tello, N., & Abed, F. (2020). Serviceability and flexural behavior of concrete beams reinforced with basalt fiber-reinforced polymer (BFRP) bars exposed to harsh conditions. Polymers, 12(9), 2110. https://doi.org/10.3390/polym12092110
Jing, L., Yin, S. P., & Duan, K. (2019). Analysis of the interface bond property between the concrete and steel bar under textile reinforced concrete confinement. Construction and Building Materials, 224, 447-454. https://doi.org/10.1016/j.conbuildmat.2019.07.102
Mak, M. W. T., & Lees, J. M. (2022). Bond strength and confinement in reinforced concrete. Construction and Building Materials, 355, 129012. https://doi.org/10.1016/j.conbuildmat.2022.129012
Harle, S. M. (2024, February). Durability and long-term performance of fiber reinforced polymer (FRP) composites: A review. In Structures (Vol. 60, p. 105881). Elsevier. https://doi.org/10.1016/j.istruc.2024.105881
Chen, Z., Yu, J., Nong, Y., Yang, Y., Zhang, H., & Tang, Y. (2023). Beyond time: Enhancing corrosion resistance of geopolymer concrete and BFRP bars in seawater. Composite Structures, 322, 117439. https://doi.org/10.1016/j.compstruct.2023.117439
El-Ghandour, A. A. (2011). Experimental and analytical investigation of CFRP flexural and shear strengthening efficiencies of RC beams. Construction and Building Materials, 25(3), 1419-1429. https://doi.org/10.1016/j.conbuildmat.2010.09.001
Hadi, M. K., Almamoori, A. H. N., & Naser, F. H. (2024, November). Load capacity of RC members subjected to marine environment and rehabilitated with FRP: State of the art review. In AIP Conference Proceedings (Vol. 3219, No. 1). AIP Publishing. https://doi.org/10.1063/5.0236570.
Guo, H., Wang, H., Xue, H., Li, H., Li, Y., & Wei, L. (2024). Study on damage deterioration mechanism and service life prediction of hybrid fibre concrete under different salt freezing conditions. Construction and Building Materials, 435, 136688. https://doi.org/10.1016/j.conbuildmat.2024.136688.
Al-Nsour, R., Abdel-Jaber, M. T., Ashteyat, A., & Shatarat, N. (2023). Flexural repairing of heat damaged reinforced concrete beams using NSM-BFRP bars and NSM-CFRP ropes. Composites Part C: Open Access, 12, 100404. https://doi.org/10.1016/j.jcomc.2023.100404.
Bunsell, A. R. (Ed.). (2018). Handbook of properties of textile and technical fibres. Woodhead Publishing. 2018, pp. 805–840.
