Advanced Retrofitting Solutions for RC Slabs: CFRP, ECC, and Steel Plate Comparison
Downloads
Retrofitting reinforced concrete (RC) slabs is crucial for enhancing their flexural strength, ductility, and durability, particularly in aging or seismically deficient structures. This study aims to evaluate and compare the effectiveness of three retrofitting techniques: steel plate bonding, carbon fiber reinforced polymer (CFRP) sheets, and engineered cementitious composites (ECC) with expanded steel mesh in improving the structural behavior of RC slabs. The research integrates both experimental testing and numerical analysis using ABAQUS finite element modeling to assess load–deflection behavior, failure mechanisms, and strength enhancement. The findings revealed that the use of CFRP sheets and ECC with expanded mesh significantly improved the slabs’ structural performance, increasing ultimate load capacity by up to 58% and ductility by more than 40% compared to the control specimens. Conversely, steel plate retrofitting showed inferior performance due to inadequate interfacial bonding. The numerical results exhibited strong agreement with the experimental data, with an average FEM-to-test ratio of 1.04. The study highlights the superior efficiency of CFRP and ECC techniques in strengthening RC slabs, offering enhanced deformation capacity, energy dissipation, and overall seismic resilience, which contributes to the ongoing development of sustainable and high-performance rehabilitation strategies for concrete structures.
Downloads
[1] Hawileh, R. A., Nawaz, W., Abdalla, J. A., & Saqan, E. I. (2015). Effect of flexural CFRP sheets on shear resistance of reinforced concrete beams. Composite Structures, 122, 468–476. doi:10.1016/j.compstruct.2014.12.010.
[2] Boyd, A. J., Banthia, N., & Mindess, S. (2009). Retrofit of shear strength deficient RC beams with sprayed GFRP. Brittle Matrix Composites 9, 1–10. doi:10.1533/9781845697754.1.
[3] Tsonos, A. G. (2008). Effectiveness of CFRP-jackets and RC-jackets in post-earthquake and pre-earthquake retrofitting of beam-column subassemblages. Engineering Structures, 30(3), 777–793. doi:10.1016/j.engstruct.2007.05.008.
[4] Ha, G. J., Kim, Y. Y., & Cho, C. G. (2008). Groove and embedding techniques using CFRP trapezoidal bars for strengthening of concrete structures. Engineering Structures, 30(4), 1067–1078. doi:10.1016/j.engstruct.2007.07.006.
[5] Varma, A. H., Ricles, J. M., Sause, R., & Lu, L.-W. (2002). Experimental Behavior of High Strength Square Concrete-Filled Steel Tube Beam-Columns. Journal of Structural Engineering, 128(3), 309–318. doi:10.1061/(asce)0733-9445(2002)128:3(309).
[6] Hueste, M. B. D., & Bai, J. W. (2007). Seismic retrofit of a reinforced concrete flat-slab structure: Part I - seismic performance evaluation. Engineering Structures, 29(6), 1165–1177. doi:10.1016/j.engstruct.2006.07.023.
[7] Reyes, J. C., Rincon, R., Yamin, L. E., Correal, J. F., Martinez, J. G., Sandoval, J. D., Gonzalez, C. D., & Angel, C. C. (2020). Seismic retrofitting of existing earthen structures using steel plates. Construction and Building Materials, 230. doi:10.1016/j.conbuildmat.2019.117039.
[8] Bonacci, J. F., & Maalej, M. (2000). Externally Bonded FRP for Service-Life Extension of RC Infrastructure. Journal of Infrastructure Systems, 6(1), 41–51. doi:10.1061/(asce)1076-0342(2000)6:1(41).
[9] Attia, M. M., Abdelsalam, B. A., Tobbala, D. E., & Rageh, B. O. (2023). Flexural behavior of strengthened concrete beams with multiple retrofitting systems. Case Studies in Construction Materials, 18. doi:10.1016/j.cscm.2023.e01862.
[10] Ganesh, P., & Murthy, A. R. (2019). Repair, retrofitting and rehabilitation techniques for strengthening of reinforced concrete beams - A review. Advances in Concrete Construction, 8(2), 101–117. doi:10.12989/ACC.2019.8.2.101.
[11] Silpa, S., & Joy, C. M. (2021). Seismic Retrofitting of Structures Using Steel Bracing: An Overview. Proceedings of International Web Conference in Civil Engineering for a Sustainable Planet, 253–261. doi:10.21467/proceedings.112.32.
[12] Olajumoke, A. M., & Dundu, M. (2014). Methods for flexural strengthening of reinforced concrete elements using steel plates. Construction Materials and Structures, IOP Press, Bristol, United Kingdom. doi:10.3233/978-1-61499-466-4-1080.
[13] Teng, J. G., Chen, J. F., Smith, S. T., & Lam, L. F. R. P. (2002). FRP: strengthened RC structures. Wiley, Hoboken, United States. doi:10.1002/pi.1312.
[14] Rusnak, C. R. (2025). Sustainable Strategies for Concrete Infrastructure Preservation: A Comprehensive Review and Perspective. Infrastructures, 10(4), 99. doi:10.3390/infrastructures10040099.
[15] Esfahani, M. R., Kianoush, M. R., & Tajari, A. R. (2007). Flexural behaviour of reinforced concrete beams strengthened by CFRP sheets. Engineering Structures, 29(10), 2428–2444. doi:10.1016/j.engstruct.2006.12.008.
[16] Todut, C., Dan, D., & Stoian, V. (2015). Numerical and experimental investigation on seismically damaged reinforced concrete wall panels retrofitted with FRP composites. Composite Structures, 119, 648–665. doi:10.1016/j.compstruct.2014.09.047.
[17] Alharty, S. E., Khalil, E. A., & Hadhod, H. M. (2023). Strengthening of Reinforced Concrete Slabs using Carbon Fiber Polymers. Journal of Engineering Sciences, 51(4), 242–254. doi:10.21608/jesaun.2023.189658.1202.
[18] Saeed, F. H., Hejazi, F., & Rashid, R. S. M. (2025). Mechanical anchorage system in retrofitting of RC slabs using CFRP rods and concrete jacket. Archives of Civil and Mechanical Engineering, 25(2), 72. doi:10.1007/s43452-025-01127-4.
[19] Alobaidi, H. E., & Al-Zuhairi, A. H. (2023). Structural Strengthening of Insufficiently Designed Reinforced Concrete T-Beams using CFRP Composites. Civil Engineering Journal, 9(8), 1880–1896. doi:10.28991/cej-2023-09-08-05.
[20] Yalcin, C., Kaya, O., & Sinangil, M. (2008). Seismic retrofitting of R/C columns having plain rebars using CFRP sheets for improved strength and ductility. Construction and Building Materials, 22(3), 295–307. doi:10.1016/j.conbuildmat.2006.08.017.
[21] Galal, K., Seif ElDin, H. M., & Tirca, L. (2012). Flexural Performance of Steel Girders Retrofitted Using CFRP Materials. Journal of Composites for Construction, 16(3), 265–276. doi:10.1061/(asce)cc.1943-5614.0000264.
[22] Lee, H. S., Shin, S. H., & Kyung, J. W. (2007). Effect of Carbon Fiber Sheets on Flexural Strengthening of RC Beams Damaged by Corrosion of Tension Rebar. Key Engineering Materials, 348–349, 437–440. doi:10.4028/www.scientific.net/kem.348-349.437.
[23] Haddad, R. H., & Harb, A. N. (2021). Varying Profiles of CFRP Ropes for Strengthening Concrete Beams. International Journal of Civil Engineering, 20(4), 405–419. doi:10.1007/s40999-021-00664-2.
[24] Chataigner, S., Benzarti, K., Foret, G., Caron, J. F., Gemignani, G., Brugiolo, M., Calderon, I., Piñero, I., Birtel, V., & Lehmann, F. (2018). Design and testing of an adhesively bonded CFRP strengthening system for steel structures. Engineering Structures, 177, 556–565. doi:10.1016/j.engstruct.2018.10.004.
[25] Yücel, H. E., Dutkiewicz, M., & Yıldızhan, F. (2022). Application of ECC as a Repair/Retrofit and Pavement/Bridge Deck Material for Sustainable Structures: A Review. Materials, 15(24), 8752. doi:10.3390/ma15248752.
[26] Shang, X., Yu, J., Li, L., & Lu, Z. (2019). Strengthening of RC Structures by Using Engineered Cementitious Composites: A Review. Sustainability, 11(12), 3384. doi:10.3390/su11123384.
[27] Kim, M. J., Chun, B., Choi, H. J., Shin, W., & Yoo, D. Y. (2021). Effects of supplementary cementitious materials and curing condition on mechanical properties of ultra-high-performance, strain-hardening cementitious composites. Applied Sciences (Switzerland), 11(5), 2394. doi:10.3390/app11052394.
[28] Arundhathy, S., & Vasugi, V. (2016). Engineered cementitious composites for sustainable construction. Key Engineering Materials, 692, 17–26. doi:10.4028/www.scientific.net/KEM.692.17.
[29] Hyun, J. H., Bang, J. W., Lee, B. Y., & Kim, Y. Y. (2021). Effects of the replacement length of concrete with ECC on the cyclic behavior of reinforced concrete columns. Materials, 14(13), 3542. doi:10.3390/ma14133542.
[30] Ma, H., Yi, C., & Wu, C. (2021). Review and outlook on durability of engineered cementitious composite (ECC). Construction and Building Materials, 287, 122719. doi:10.1016/j.conbuildmat.2021.122719.
[31] Li, V. C. (2003). On Engineered Cementitious Composites (ECC). Journal of Advanced Concrete Technology, 1(3), 215–230. doi:10.3151/jact.1.215.
[32] Hu, Z., Elchalakani, M., Yehia, S., Ran, H., Sadakkathulla, M. A., & Guo, X. (2024). Engineered cementitious composite (ECC) strengthening of reinforced concrete structures: A state-of-the-art review. Journal of Building Engineering, 86, 108941. doi:10.1016/j.jobe.2024.108941.
[33] Sagare, S. S., Kirthiga, R., & Elavenil, S. (2024). A state of art of review on strengthening of concrete structures using fabric reinforced cementitious matrix. Research on Engineering Structures and Materials, 10(3), 1231–1260. doi:10.17515/resm2024.133ma1226rv.
[34] ACI 318-19. (2022). Building code requirements for structural concrete and commentary. American Concrete Institute (ACI), Farmington Hills, United States.
[35] Mhalhal, J. M., Al-Gasham, T. S., & Abid, S. R. (2020). Tests on reinforced concrete deep beams with different web reinforcement types. IOP Conference Series: Materials Science and Engineering, 988(1), 12032. doi:10.1088/1757-899X/988/1/012032.
[36] Al-Gasham, T. S., Mhalhal, J. M., & Abid, S. R. (2020). Evaluating planner hoop steel plates as web reinforcement for deep reinforced concrete beams. IOP Conference Series: Materials Science and Engineering, 988(1), 12031. doi:10.1088/1757-899X/988/1/012031.
[37] Jabir, H. A., Mhalhal, J. M., Al-Gasham, T. S., & Abid, S. R. (2020). Mechanical characteristics of deep beams considering variable a/d ratios: An experimental investigation. IOP Conference Series: Materials Science and Engineering, 988(1), 12030. doi:10.1088/1757-899X/988/1/012030.
[38] ASTM C39/C39M-05. (2003). Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens. ASTM International, Pennsylvania, United States. doi:10.1520/C0039_C0039M-05.
[39] Dassault Systèmes. (2016). Abaqus 2016 documentation. Dassault Systèmes, Vélizy-Villacoublay, France.
[40] Zhang, D., Wang, Q., & Dong, J. (2016). Simulation study on CFRP strengthened reinforced concrete beam under four-point bending. Computers and Concrete, 17(3), 407–421. doi:10.12989/cac.2016.17.3.407.
[41] Ibrahim, S. K., & Rad, M. M. (2020). Numerical Plastic Analysis of Non-Prismatic Reinforced Concrete Beams Strengthened by Carbon Fiber Reinforced Polymers. Proceedings of the 13th fib International Ph.D. Symposium in Civil Engineering, 26-28 August, Paris, France.
[42] Camanho, P. P. (2001). Numerical simulation of delamination growth in composite materials. NASA Langley Research Center, National Aeronautics and Space Administration (NASA), Washington, United States.
[43] Jin, L., Jiang, X., Lu, K., & Du, X. (2022). Tests on shear failure and size effect of CFRP-wrapped RC beams without stirrups: Influence of CFRP ratio. Composite Structures, 291, 115613. doi:10.1016/j.compstruct.2022.115613.
[44] Qazi, A. U., Rasool, A. M., Din Afzal, M. F. U., Hameed, A., Mahmood, N., & Yaseen, N. (2024). Strengthening and retrofitting of low strength reinforced concrete slabs with high strength overlay: experimental and numerical investigation. International Journal of Structural Engineering, 14(4), 416–436. doi:10.1504/IJSTRUCTE.2024.142108.
[45] Lattif, Y., & Hamdy, O. (2022). An experimental investigation of the flexural strengthening of preloaded self-compacted RC beams using CFRP sheets and laminates composites. Advances in Concrete Construction, 13(4), 307–313. doi:10.12989/acc.2022.13.4.307.
[46] Samarakoon, S. M. S. M. K., Piatek, B., & De Silva, G. H. M. J. S. (2023). Investigation of the Flexural Behavior of Preloaded and Pre-Cracked Reinforced Concrete Beams Strengthened with CFRP Plates. Materials, 16(1), 22. doi:10.3390/ma16010022.
[47] Abd Elmoaty, A. E. M., Morsy, A. M., & Harraz, A. B. (2022). Effect of Fiber Type and Volume Fraction on Fiber Reinforced Concrete and Engineered Cementitious Composite Mechanical Properties. Buildings, 12(12), 2108. doi:10.3390/buildings12122108.
[48] Breveglieri, M., & Czaderski, C. (2021). RC slabs strengthened with externally bonded CFRP strips under long-term environmental exposure and sustained loading. Part 2: Laboratory experiments. Composites Part C: Open Access, 6. doi:10.1016/j.jcomc.2021.100210.
[49] Yang, X., Wang, X. D., Lin, Z. H., & Peng, H. (2025). Corroded RC slabs retrofitted with FRP grid-reinforced ECC matrix composites. Advances in Structural Engineering, 28(13), 2538–2556. doi:10.1177/13694332251334828.
[50] Ahamed, M. K., Wang, H., Ameri, A., & Hazell, P. J. (2023). Nacre-inspired design of engineered cementitious composite (ECC) beams for enhanced impact resistance and energy absorption. Journal of Building Engineering, 78. doi:10.1016/j.jobe.2023.107687.
- Authors retain all copyrights. It is noticeable that authors will not be forced to sign any copyright transfer agreements.
- This work (including HTML and PDF Files) is licensed under a Creative Commons Attribution 4.0 International License.
