Civil Engineering and Architecture Vol. 13(3A), pp. 2396 - 2404
DOI: 10.13189/cea.2025.131317
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Repairing and Strengthening Defective Reinforced Concrete Columns Using Ultra-High Performance Concrete Jacketing

Mohammad Waleed AL-Ahmad , Mohammed Salman AL-Lami ^*
Department of Civil Engineering, Faculty of Engineering, Isra University, Jordan

ABSTRACT

Ultra-High Performance Concrete (UHPC) is a modern concrete technology that has gained popularity recently. It is characterized by exceptional compressive strength compared to Normal Concrete (NC), which ranges from 120 MPa to 180 MPa and more. Many researchers tried to use this type of concrete to strengthen the structural elements, and the result shows that UHPC might be a good alternative to strengthening techniques that use less weight and thickness. In this paper, an experimental program was conducted to study the feasibility of using a UHPC jacket to repair and strengthen defective reinforced concrete columns. Five Reinforced Concrete (RC) columns were cast using Normal Concrete (NC), and four of them were cast without concrete cover as defects. The UHPC jackets were cast with maximum compressive strength obtained from trial mixtures reaching 123.6 MPa at 28 age days and different jacket thicknesses of 20 mm, 30 mm and 40 mm. The results showed that using the UHPC as a jacketing helps increase maximum capacity load efficiency, reaching up to 253.3% compared with defective RC columns. All the jacket specimens had a failure in the way of spalling, where the jacket's failure method was predictable before its occurrence, as the failure occurred gradually, from a hairline crack to a complete failure, due to the use of steel fiber, which helped prevent the expansion of cracks. Further on, the results showed that the jacket thicknesses had a clear effect on the behavior of the columns. Whereas the thickness of 20 mm and 30 mm gave a better improvement, neither of these thicknesses was able to restore the defective RC column to its original condition. A column with a jacket thickness of 40 mm can restore the defective RC column and result in more than 17% improvement compared with its original condition.

KEYWORDS
Ultra-High Performance Concrete, Normal Concrete, Defective Reinforced Concrete Columns, Concrete Jacket, Compressive Strength, Repair, Strengthening

Cite This Paper in IEEE or APA Citation Styles
(a). IEEE Format:
[1] Mohammad Waleed AL-Ahmad , Mohammed Salman AL-Lami , "Repairing and Strengthening Defective Reinforced Concrete Columns Using Ultra-High Performance Concrete Jacketing," Civil Engineering and Architecture, Vol. 13, No. 3A, pp. 2396 - 2404, 2025. DOI: 10.13189/cea.2025.131317.

(b). APA Format:
Mohammad Waleed AL-Ahmad , Mohammed Salman AL-Lami (2025). Repairing and Strengthening Defective Reinforced Concrete Columns Using Ultra-High Performance Concrete Jacketing. Civil Engineering and Architecture, 13(3A), 2396 - 2404. DOI: 10.13189/cea.2025.131317.