The Influence of a Damaged Concrete Cover on the Behavior of a Simply-Supported Beam

Khalid K. Shadhan, Bilal Ismaeel Abd Al-Zahra, Muhammad Jawad Kadhim


The concrete cover is a part of the concrete that provides the required protection for the reinforcing steel within the required element from external effects. This concrete cover can be damaged for an assortment of reasons, one of which is environmental factors. As a result, this research focused on the effect of worn concrete covering on the structural response of beams. Moreover, the possibility of repairing or replacing this concrete cover with a cement material was done by testing seven beams with the exact dimensions (2700 mm long, 250 mm deep, and 140 mm wide). The first specimen was a control specimen, while in the remaining specimens, a part of the concrete cover was removed in the midspan region with a length of 600 mm and in different formats. The part below the neutral axis (tension zone) was removed in the first two specimens. The part above the neutral axis (the compression zone) was removed in the second two specimens. The whole cover was removed within the specified distance for the other two specimens. In one out of every two of these six specimens, the removed concrete cover was replaced with cementitious material. A flexural test was performed for all specimens, and the conclusion was reached that damaging or removing the concrete cover from the tensile region (below the neutral axis) is less harmful than from the compression region since the beam is often designed as a cracked section. Also, removing the concrete cover from the compression region gives cracks a greater width than removing the concrete cover from the tension region at the same loading level. In the case of replacing the concrete cover with a cementitious one, if the replacement is in the compression zone, it will result in cracks when loading with a width greater than that of the rest of the cases. For specimens that removed their concrete covers from the tension zone, compression zone, and the whole section, the failure loads decreased by 39%, 20%, and 23%, respectively, concerning the control beam. In contrast, all these specimens were repaired with cementitious materials, with an ultimate load capacity approximately equal to the control beams. From these results, any damaged concrete cover for beams in any zone with cementitious materials having high strength and a good bond with old concrete sections can be repaired.


Doi: 10.28991/CEJ-2023-09-07-09

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Reinforced Concrete; Simply-Supported Beam; Concrete Cover; Repairing.


Rahal, K. N. (2006). Shear behavior of reinforced concrete beams with variable thickness of concrete side cover. ACI Structural Journal, 103(2), 171–177. doi:10.14359/15174.

Zakaria, M., Ueda, T., Wu, Z., & Meng, L. (2009). Experimental Investigation on Shear Cracking Behavior in Reinforced Concrete Beams with Shear Reinforcement. Journal of Advanced Concrete Technology, 7(1), 79–96. doi:10.3151/jact.7.79

Wakchaure, M. R., Gite, B. E., & Shaikh, A. P. (2012). Effect of concrete cover on crack width of RC beams. Advanced Engineering Informatics, 47, 8782–8785.

He, H., & Cheng, L. (2016). Effect of BFRP Grid on Crack Propagation of Reinforced Concrete Beam with Thick-Cover Concrete. Proceedings of the 5th International Conference on the Durability of Concrete Structures. doi:10.5703/1288284316124.

Zhang, W., Zhang, H., Gu, X., & Liu, W. (2018). Structural behavior of corroded reinforced concrete beams under sustained loading. Construction and Building Materials, 174, 675–683. doi:10.1016/j.conbuildmat.2018.04.145.

Khalaf, J., & Huang, Z. (2019). The bond behaviour of reinforced concrete members at elevated temperatures. Fire Safety Journal, 103, 19–33. doi:10.1016/j.firesaf.2018.12.002.

Khiyon, M. I., Kadir, M. A. A., Mohd Sam, A. R., Hasanah, N., Mohamed, R. N., Yussof, M. M., Mohamad Zukri, S. N. N., & Nurizaty, Z. (2019). The effect of concrete cover thickness subjected to elevated temperatures. IOP Conference Series: Materials Science and Engineering, 620(1), 012054. doi:10.1088/1757-899x/620/1/012054.

Muhdin, A. (2019). The Effect of Concrete Cover on Pure Torsional Resistance in Reinforced Concrete Beam- Experimental Investigation. Master Thesis, Addis Ababa University, Addis Ababa, Ethiopia.

Wang, X., Liu, Y., Yang, F., Lu, Y., & Li, X. (2019). Effect of concrete cover on the bond-slip behavior between steel section and concrete in SRC structures. Construction and Building Materials, 229. doi:10.1016/j.conbuildmat.2019.116855.

Ibrahim, M. S., Gebreyouhannes, E., Muhdin, A., & Gebre, A. (2020). Effect of concrete cover on the pure torsional behavior of reinforced concrete beams. Engineering Structures, 216, 110790. doi:10.1016/j.engstruct.2020.110790.

Vishal, M., & Satyanarayanan, K. S. (2023). Study on optimum concrete cover thickness in RC beam and columns under high temperature. Journal of Structural Fire Engineering. doi:10.1108/JSFE-11-2022-0035.

Hou, X., Ren, P., Rong, Q., Zheng, W., & Zhan, Y. (2019). Effect of fire insulation on fire resistance of hybrid-fiber reinforced reactive powder concrete beams. Composite Structures, 209, 219-232. doi:10.1016/j.jcsr.2018.02.038.

Said, A., Elsayed, M., Abd El-Azim, A., Althoey, F., & Tayeh, B. A. (2022). Using ultra-high performance fiber reinforced concrete in improvement shear strength of reinforced concrete beams. Case Studies in Construction Materials, 16, e01009. doi:10.1016/j.cscm.2022.e01009.

Hassan, A., Arif, M., & Shariq, M. (2020). A review of properties and behaviour of reinforced geopolymer concrete structural elements-A clean technology option for sustainable development. Journal of Cleaner Production, 245, 118762. doi:10.1016/j.jclepro.2019.118762.

Yang, D., Huang, S. S., Liu, F., & Yang, H. (2022). Structural fire design of square tubed-reinforced-concrete columns with connection to RC beams in composite frames. Journal of Building Engineering, 57, 104900. doi:10.1016/j.jobe.2022.104900.

Alkhawaldeh, A. A., & Al-Rousan, R. Z. (2022). Upgrading cyclic response of heat-damaged RC beam-column joints using CFRP sheets. Case Studies in Construction Materials, 17, e01699. doi:10.1016/j.cscm.2022.e01699.

Ferguson, P. M. (1981). Reinforced Concrete Fundamentals: SI version (4th Ed.). Wiley, New York, United States.

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DOI: 10.28991/CEJ-2023-09-07-09


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