journal article·2025-07-17Open access

Performance of Rubberized RC Beams Flexural-Strengthened Using Near-Surface Mounted Systems

Mohamed Emara, Abdulrahman H. Mostafa, Heba A. Mohamed, Mahmoud Zaghlal

Abstract

Abstract This research investigates the flexural performance of strengthened rubberized concrete beams via bottom, side, and hybrid near-surface mounted (NSM) approaches using GFRP/steel rebars. Eleven strengthened specimens, alongside one control, were subjected to four-point loading setup till failure. The investigation focused on three key parameters: strengthening technique (bottom, side, or hybrid), NSM bar area, and bar type (GFRP or steel). The results revealed significant improvements across various performance metrics. It was demonstrated that NSM strengthening enhanced the beam’s cracking loads by up to 90%. Correspondingly, the strengthened beam’s yield and ultimate loads witnessed enhancements up to 48% and 79%, respectively. Notably, the load-carrying ability of GFRP bars consistently outperformed steel bars. Additionally, increasing the quantity of NSM strengthening proved beneficial, with bottom placement offering a slight advantage due to a larger internal lever arm. The proposed hybrid NSM technique, employing three 8-mm-diameter GFRP bars, emerged as the most effective strengthening scheme. However, utilizing four bars resulted in decreased effectiveness due to overlapping tensile stresses and accelerated debonding failure. Finally, the experimental results were compared to analytical predictions, with close agreement observed. The experimental-to-predicted analytical result ratio varies from 0.84 to 1.01%, indicating the validity of the analytical approach.
Source: crossref · Quality: baseline

Research context

OpenAlex topics: Structural Behavior of Reinforced Concrete · Concrete Corrosion and Durability · Innovative concrete reinforcement materials

SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.

References (65)

Show source-provided references
1. Abdalla, J. A., Ali, A. B., Hawileh, R. A., Mhanna, H. H., Galal, K. E., & Saqan, E. I. (2023). Effect of CFRP anchorages on the flexural behavior of externally strengthened reinforced concrete beams. Archives of Civil and Mechanical Engineering. https://doi.org/10.1007/s43452-023-00784-710.1007/s43452-023-00784-7 ↗
2. Abdalla, J. A., Mohammed, A., & Hawileh, R. A. (2020). Flexural strengthening of reinforced concrete beams with externally bonded hybrid systems. Procedia Structural Integrity. https://doi.org/10.1016/j.prostr.2020.11.07810.1016/j.prostr.2020.11.078 ↗
3. Abdallah, M., Al Mahmoud, F., Boissière, R., Khelil, A., & Mercier, J. (2020). Experimental study on strengthening of RC beams with side near surface mounted technique-CFRP bars. Composite Structures, 234, 111716. https://doi.org/10.1016/j.compstruct.2019.11171610.1016/j.compstruct.2019.111716 ↗
4. ACI Committee 440.2R-17. (2017). Guide for the design and construction of externally bonded FRP systems for strengthening concrete structures. ACI Report, American Concrete Institute.
5. Almusallam, T. H., Elsanadedy, H. M., Al-Salloum, Y. A., & Alsayed, S. H. (2013). Experimental and numerical investigation for the flexural strengthening of RC beams using near-surface mounted steel or GFRP bars. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2012.09.10710.1016/j.conbuildmat.2012.09.107 ↗
6. Al-Saadi, N. T. K., Mohammed, A., Al-Mahaidi, R., & Sanjayan, J. (2019). A state-of-the-art review: Near-surface mounted FRP composites for reinforced concrete structures. Construction and Building Materials, 209, 748–769. https://doi.org/10.1016/j.conbuildmat.2019.03.12110.1016/j.conbuildmat.2019.03.121 ↗
7. Assad, M., Hawileh, R. A., & Abdalla, J. A. (2024). Flexural strengthening of reinforced concrete beams with CFRP laminates and spike anchors. Composites Part c: Open Access. https://doi.org/10.1016/j.jcomc.2024.10044310.1016/j.jcomc.2024.100443 ↗
8. Attari, N., Amziane, S., & Chemrouk, M. (2012). Flexural strengthening of concrete beams using CFRP, GFRP and hybrid FRP sheets. Construction and Building Materials, 37, 746–757. https://doi.org/10.1016/j.conbuildmat.2012.07.05210.1016/j.conbuildmat.2012.07.052 ↗
9. Barros, J. A. O., Dias, S. J. E., & Lima, J. L. T. (2007). Efficacy of CFRP-based techniques for the flexural and shear strengthening of concrete beams. Cement and Concrete Composites, 29, 203–217. https://doi.org/10.1016/j.cemconcomp.2006.09.00110.1016/j.cemconcomp.2006.09.001 ↗
10. Bilotta, A., Ceroni, F., Di Ludovico, M., Nigro, E., Pecce, M., & Manfredi, G. (2011). Bond efficiency of EBR and NSM FRP systems for strengthening concrete members. Journal of Composites for Construction, 15, 757–772. https://doi.org/10.1061/(ASCE)CC.1943-5614.000020410.1061/(ASCE)CC.1943-5614.0000204 ↗
11. Bilotta, A., Ceroni, F., Nigro, E., & Pecce, M. (2015). Efficiency of CFRP NSM strips and EBR plates for flexural strengthening of RC beams and loading pattern influence. Composite Structures, 124, 163–175. https://doi.org/10.1016/j.compstruct.2014.12.04610.1016/j.compstruct.2014.12.046 ↗
12. BS EN 12390-3:2009. (2009). Testing hardened concrete—Part 3: Compressive strength of test specimens.
13. BS EN 12390-6:2009. (2009). Testing hardened concrete—Part 6: Tensile splitting strength of test specimens.
14. Ceroni, F., & Pecce, M. (2012). Statistical analysis of debonding load in concrete elements externally strengthened with CFRP materials. Advances in Structural Engineering, 15, 155–168.10.1260/1369-4332.15.1.155 ↗
15. Darain, K. M. U., Jumaat, M. Z., Hossain, M. A., Hosen, M. A., Obaydullah, M., Huda, M. N., & Hossain, I. (2015). Automated serviceability prediction of NSM strengthened structure using a fuzzy logic expert system. Expert Systems with Applications. https://doi.org/10.1016/j.eswa.2014.07.05810.1016/j.eswa.2014.07.058 ↗
16. De Domenico, D., Fuschi, P., Pardo, S., & Pisano, A. A. (2014). Strengthening of steel-reinforced concrete structural elements by externally bonded FRP sheets and evaluation of their load carrying capacity. Composite Structures, 118, 377–384. https://doi.org/10.1016/j.compstruct.2014.07.04010.1016/j.compstruct.2014.07.040 ↗
17. De Lorenzis, L. (2000). Strengthening of RC structures with near surface mounted FRP rods.
18. De Lorenzis, L., & Teng, J. G. (2007). Near-surface mounted FRP reinforcement: An emerging technique for strengthening structures. Composites Part b: Engineering, 38, 119–143. https://doi.org/10.1016/j.compositesb.2006.08.00310.1016/j.compositesb.2006.08.003 ↗
19. Emara, M., Elkomy, N., & Hassan, H. (2021). Numerical assessment of reinforced concrete beams strengthened with CFRP sheets under impact loading. Frattura Ed Integrita Strutturale-Fracture and Structural Integrity. https://doi.org/10.3221/IGF-ESIS.58.0410.3221/IGF-ESIS.58.04 ↗
20. Emara, M., El-Zohairy, A., Fekry, M., & Husain, M. (2022). Effect of using ECC layer on the flexural performance of rc beams previously strengthened with EB CFRP laminates. Sustainability (Switzerland). https://doi.org/10.3390/su14241699010.3390/su142416990 ↗
21. Emara, M., Hamoda, A., & Hu, J. W. (2023a). Numerical assessment of rectangular one- and two-way RC slabs strengthened with CFRP under impact loads. Computers and Concrete, 31, 173–184. https://doi.org/10.12989/cac.2023.31.3.17310.12989/cac.2023.31.3.173 ↗
22. Emara, M., Salem, M. A., Mohamed, H. A., Shehab, H. A., El-Zohairy, A., & Sharma, A. (2023b). Shear strengthening of reinforced concrete beams using engineered cementitious composites and carbon fiber-reinforced polymer sheets. Fibers. https://doi.org/10.3390/fib1111009810.3390/fib11110098 ↗
23. Gerges, N. N., Issa, C. A., & Fawaz, S. A. (2018). Rubber concrete: Mechanical and dynamical properties. Case Studies in Construction Materials, 9, e00184. https://doi.org/10.1016/j.cscm.2018.e0018410.1016/j.cscm.2018.e00184 ↗
24. Gopinath, S., Murthy, A. R., & Patrawala, H. (2016). Near surface mounted strengthening of RC beams using basalt fiber reinforced polymer bars. Construction and Building Materials, 111, 1–8. https://doi.org/10.1016/j.conbuildmat.2016.02.04610.1016/j.conbuildmat.2016.02.046 ↗
25. Hawileh, R. A., Nawaz, W., & Abdalla, J. A. (2018). Flexural behavior of reinforced concrete beams externally strengthened with hardwire steel-fiber sheets. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2018.03.22510.1016/j.conbuildmat.2018.03.225 ↗
26. 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. https://doi.org/10.1016/j.compstruct.2014.12.01010.1016/j.compstruct.2014.12.010 ↗
27. Hawileh, R. A., Rasheed, H. A., Abdalla, J. A., & Al-Tamimi, A. K. (2014). Behavior of reinforced concrete beams strengthened with externally bonded hybrid fiber reinforced polymer systems. Materials and Design, 53, 972–982. https://doi.org/10.1016/j.matdes.2013.07.08710.1016/j.matdes.2013.07.087 ↗
28. Hawileh, R. A., Salama, A. S. D., Mhanna, H. H., Assad, M., Abdalla, J. A., & Saqan, E. I. (2024). Flexural behavior of RC beams externally strengthened with side-bonded CFRP laminates with variable internal reinforcement. Engineering Structures, 318, 118707. https://doi.org/10.1016/j.engstruct.2024.11870710.1016/j.engstruct.2024.118707 ↗
29. Hosen, M. A., Al Kaaf, K. A., Islam, A. B. M. S., Jumaat, M. Z., & Kazmi, Z. A. (2023a). Behavior and modeling of RC beams strengthened with NSM-steel technique. Structural Engineering and Mechanics. https://doi.org/10.12989/sem.2023.88.1.06710.12989/sem.2023.88.1.067 ↗
30. Hosen, M. A., Jumaat, M. Z., Alengaram, U. J., Islam, A. B. M. S., & bin Hashim, H. (2016b). Near surface mounted composites for flexural strengthening of reinforced concrete beams. Polymers (Basel). https://doi.org/10.3390/polym803006710.3390/polym8030067 ↗
31. Hosen, Md. A., Jumaat, M. Z., Alengaram, U. J., & Ramli Sulong, N. H. (2018). CFRP strips for enhancing flexural performance of RC beams by SNSM strengthening technique. Construction and Building Materials, 165, 28–44. https://doi.org/10.1016/j.conbuildmat.2017.12.05210.1016/j.conbuildmat.2017.12.052 ↗
32. Hosen, M. A., Jumaat, M. Z., Alengaram, U. J., Sulong, N. H. R., & Alsubari, B. (2019). Sustainable palm oil fuel ash mortar used as partial adhesive replacement in flexurally strengthened RC beams. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2019.07.22210.1016/j.conbuildmat.2019.07.222 ↗
33. Hosen, M. A., Jumaat, M. Z., Alsubari, B., Sulong, N. H. R., Ibrahim, Z., Alengaram, U. J., & Hashim, H. (2020). Effect of bonding materials on the flexural improvement in RC beams strengthened with SNSM technique using GFRP bars. Journal of Building Engineering. https://doi.org/10.1016/j.jobe.2020.10177710.1016/j.jobe.2020.101777 ↗
34. Hosen, M. A., Jumaat, M. Z., & Islam, A. B. M. S. (2015c). Side near surface mounted (SNSM) technique for flexural enhancement of RC beams. Materials and Design, 83, 587–597. https://doi.org/10.1016/j.matdes.2015.06.03510.1016/j.matdes.2015.06.035 ↗
35. Hosen, M. A., Jumaat, M. Z., Islam, A. B. M. S., Kamruzzaman, M., Huda, M. N., & Soeb, M. R. (2015a). Eliminating concrete cover separation of NSM strengthened beams by CFRP end anchorage. Structural Engineering and Mechanics. https://doi.org/10.12989/sem.2015.56.6.89910.12989/sem.2015.56.6.899 ↗
36. Hosen, M. A., Jumaat, M. Z., Islam, A. B. M. S., Obaydullah, M., Darain, K. M., & Huda, M. N. (2016a). Investigation on energy absorption capacity of reinforced concrete beams by the near-surface mounted technique using ductile materials. Science of Advanced Materials. https://doi.org/10.1166/sam.2016.275710.1166/sam.2016.2757 ↗
37. Hosen, M. A., Jumaat, M. Z., & Saiful Islam, A. B. M. (2015b). Inclusion of CFRP-epoxy composite for end anchorage in NSM-epoxy strengthened beams. Advances in Materials Science and Engineering. https://doi.org/10.1155/2015/81279710.1155/2015/812797 ↗
38. Hosen, M. A., Jumaat, M. Z., Saiful Islam, A. B. M., Al Kaaf, K. A., Shammas, M. I., Hakeem, I. Y., & Ul Islam, M. M. (2023b). Potential side-NSM strengthening approach to enhance the flexural performance of RC beams: Experimental, numerical and analytical investigations. Structural Engineering and Mechanics. https://doi.org/10.12989/sem.2023.85.2.17910.12989/sem.2023.85.2.179 ↗
39. Hosen, M. A., Jumaat, M. Z., Saiful Islam, A. B. M., Salam, M. A., & Mo, K. H. (2017a). Side-NSM composite technique for flexural strengthening of RC beams. Computers and Concrete. https://doi.org/10.12989/cac.2017.20.4.43910.12989/cac.2017.20.4.439 ↗
40. Hosen, Md. A., Alengaram, U. J., Jumaat, Z., Sulong, H., & ud Darain, K. M. (2017b). Glass fiber reinforced polymer (GFRP) bars for enhancing the flexural performance of rc beams using side-NSM technique. Polymers (Basel), 9, 180. https://doi.org/10.3390/polym905018010.3390/polym9050180 ↗
41. Imjai, T., Setkit, M., Figueiredo, F. P., Garcia, R., Sae-Long, W., & Limkatanyu, S. (2022). Experimental and numerical investigation on low-strength RC beams strengthened with side or bottom near surface mounted FRP rods. Structure and Infrastructure Engineering. https://doi.org/10.1080/15732479.2022.204561310.1080/15732479.2022.2045613 ↗
42. Khalifa, A. M. (2016). Flexural performance of RC beams strengthened with near surface mounted CFRP strips. Alexandria Engineering Journal, 55, 1497–1505. https://doi.org/10.1016/j.aej.2016.01.03310.1016/j.aej.2016.01.033 ↗
43. Khatib, Z. K., & Bayomy, F. M. (1999). Rubberized Portland cement concrete. Journal of Materials in Civil Engineering, 11, 206–213. https://www.tib.eu/de/suchen/id/BLSE%3ARN06451679610.1061/(ASCE)0899-1561(1999)11:3(206) ↗
44. Kotynia, R. (2012). Bond between FRP and concrete in reinforced concrete beams strengthened with near surface mounted and externally bonded reinforcement. Construction and Building Materials, 32, 41–54. https://doi.org/10.1016/j.conbuildmat.2010.11.10410.1016/j.conbuildmat.2010.11.104 ↗
45. Kusuma, Y., Rashmi, T., Anand, V. N., & Balaji, N. C. (2022). An experimental study on flexural performance of RC beams strengthened by NSM technique using GFRP strips for a resilient infrastructure system. Materials Today: Proceedings, 52, 1959–1967. https://doi.org/10.1016/j.matpr.2021.11.60010.1016/j.matpr.2021.11.600 ↗
46. Mendis, A. S. M., Al-Deen, S., & Ashraf, M. (2017a). Behaviour of similar strength crumbed rubber concrete (CRC) mixes with different mix proportions. Construction and Building Materials, 137, 354–366. https://doi.org/10.1016/j.conbuildmat.2017.01.12510.1016/j.conbuildmat.2017.01.125 ↗
47. Mendis, A. S. M., Al-Deen, S., & Ashraf, M. (2017b). Effect of rubber particles on the flexural behaviour of reinforced crumbed rubber concrete beams. Construction and Building Materials, 154, 644–657. https://doi.org/10.1016/j.conbuildmat.2017.07.22010.1016/j.conbuildmat.2017.07.220 ↗
48. Mhanna, H. H., Hawileh, R. A., & Abdalla, J. A. (2019). Shear strengthening of reinforced concrete beams using CFRP wraps. Procedia Structural Integrity. https://doi.org/10.1016/j.prostr.2019.08.02910.1016/j.prostr.2019.08.029 ↗
49. Mostofinejad, D., & Moghaddas, A. (2014). Bond efficiency of EBR and EBROG methods in different flexural failure mechanisms of FRP strengthened RC beams. Construction and Building Materials, 54, 605–614. https://doi.org/10.1016/j.conbuildmat.2014.01.00210.1016/j.conbuildmat.2014.01.002 ↗
50. Mustafa, S., Shaaban, H., & Elshazly, F. (2020). Rubberized concrete properties and its structural engineering applications—An overview. Egyptian Journal for Engineering Sciences and Technology, 30, 1–11. https://doi.org/10.21608/EIJEST.2020.35823.100010.21608/EIJEST.2020.35823.1000 ↗
51. Nawaz, W., Elchalakani, M., Karrech, A., Yehia, S., Yang, B., & Youssf, O. (2022). Flexural behavior of all lightweight reinforced concrete beams externally strengthened with CFRP sheets. Construction and Building Materials, 327, 126966. https://doi.org/10.1016/j.conbuildmat.2022.12696610.1016/j.conbuildmat.2022.126966 ↗
52. Nayak, A. N., Kumari, A., & Swain, R. B. (2018). Strengthening of RC beams using externally bonded fibre reinforced polymer composites. Structures, 14, 137–152. https://doi.org/10.1016/j.istruc.2018.03.00410.1016/j.istruc.2018.03.004 ↗
53. Rahman, M. M., Jumat, M. Z., Hosen, M. A., & Saiful Islam, A. B. M. (2016). Effect of adhesive replacement with cement mortar on NSM strengthened RC beam. Revista De La Construccion. https://doi.org/10.4067/s0718-915x201600010000610.4067/s0718-915x2016000100006 ↗
54. Reda, R. M., Sharaky, I. A., Ghanem, M., Seleem, M. H., & Sallam, H. E. M. (2016). Flexural behavior of RC beams strengthened by NSM GFRP Bars having different end conditions. Composite Structures, 147, 131–142. https://doi.org/10.1016/j.compstruct.2016.03.01810.1016/j.compstruct.2016.03.018 ↗
55. Sabau, C., Popescu, C., Sas, G., Schmidt, J. W., Blanksvärd, T., & Täljsten, B. (2018). Strengthening of RC beams using bottom and side NSM reinforcement. Composites Part b: Engineering, 149, 82–91. https://doi.org/10.1016/j.compositesb.2018.05.01110.1016/j.compositesb.2018.05.011 ↗
56. Saqan, E. I., Rasheed, H. A., & Hawileh, R. A. (2013). An efficient design procedure for flexural strengthening of RC beams based on ACI 440.2R–08. Composites Part b: Engineering. https://doi.org/10.1016/j.compositesb.2013.01.00610.1016/j.compositesb.2013.01.006 ↗
57. Sharaky, I. A., Mohamed, H. A., Torres, L., & Emara, M. (2020). Flexural behavior of rubberized concrete beams strengthened in shear using welded wire mesh. Composite Structures, 247, 112485. https://doi.org/10.1016/j.compstruct.2020.11248510.1016/j.compstruct.2020.112485 ↗
58. Sharaky, I. A., Torres, L., & Sallam, H. E. M. (2015). Experimental and analytical investigation into the flexural performance of RC beams with partially and fully bonded NSM FRP bars/strips. Composite Structures, 122, 113–126. https://doi.org/10.1016/j.compstruct.2014.11.05710.1016/j.compstruct.2014.11.057 ↗
59. Shukri, A. A., Hosen, M. A., Muhamad, R., & Jumaat, M. Z. (2016). Behaviour of precracked RC beams strengthened using the side-NSM technique. Construction and Building Materials. https://doi.org/10.1016/j.conbuildmat.2016.07.06610.1016/j.conbuildmat.2016.07.066 ↗
60. Siddika, A., Al Mamun, M. A., Ferdous, W., & Alyousef, R. (2020). Performances, challenges and opportunities in strengthening reinforced concrete structures by using FRPs—A state-of-the-art review. Engineering Failure Analysis, 111, 104480. https://doi.org/10.1016/j.engfailanal.2020.10448010.1016/j.engfailanal.2020.104480 ↗
61. Tang, W. C., Balendran, R. V., Nadeem, A., & Leung, H. Y. (2006). Flexural strengthening of reinforced lightweight polystyrene aggregate concrete beams with near-surface mounted GFRP bars. Building and Environment, 41, 1381–1393. https://doi.org/10.1016/j.buildenv.2005.05.02910.1016/j.buildenv.2005.05.029 ↗
62. Toutanji, H. A. (1996). The use of rubber tire particles in concrete to replace mineral aggregates. Cement and Concrete Composites, 18, 135–139. https://doi.org/10.1016/0958-9465(95)00010-010.1016/0958-9465(95)00010-0 ↗
63. Xue, J., & Shinozuka, M. (2013). Rubberized concrete: A green structural material with enhanced energy-dissipation capability. Construction and Building Materials, 42, 196–204. https://doi.org/10.1016/j.conbuildmat.2013.01.00510.1016/j.conbuildmat.2013.01.005 ↗
64. Yasser, N., Abdelrahman, A., Kohail, M., & Moustafa, A. (2023). Experimental investigation of durability properties of rubberized concrete. Ain Shams Engineering Journal, 14, 102111. https://doi.org/10.1016/j.asej.2022.10211110.1016/j.asej.2022.102111 ↗
65. Zhang, S. S., Yu, T., & Chen, G. M. (2017). Reinforced concrete beams strengthened in flexure with near-surface mounted (NSM) CFRP strips: Current status and research needs. Composites Part b: Engineering, 131, 30–42. https://doi.org/10.1016/j.compositesb.2017.07.07210.1016/j.compositesb.2017.07.072 ↗