Methods for Reducing Concrete Cover De-bonding in R.C. Beams Strengthened in Flexure with CFRP Strips

International Journal of Civil Engineering
© 2017 by SSRG - IJCE Journal
Volume 4 Issue 11
Year of Publication : 2017
Authors : Alaa M. Morsy, Nabil H. El-Ashkar, T. M. Elrakib
How to Cite?

Alaa M. Morsy, Nabil H. El-Ashkar, T. M. Elrakib, "Methods for Reducing Concrete Cover De-bonding in R.C. Beams Strengthened in Flexure with CFRP Strips," SSRG International Journal of Civil Engineering, vol. 4,  no. 11, pp. 8-13, 2017. Crossref,


In many cases beams need repair due to steel corrosion. The traditional method for beam repair due to steel reinforcement corrosion is removing the concrete cover to repair the longitudinal steel bars then recasting it again using new concrete cover which considered as a weak point when this member is strengthened with CFRP strips. This technique may lead to de-bonding of the new concrete cover and the strengthened member will fail in a brittle manner without reaching the full effect of strengthening. This research investigates the effect of the compressive strength of the concrete cover compared with that of the old concrete. It also introduces some new techniques for reducing and preventing the concrete cover de-bonding and compares it with a control beam which had no concrete cover removal. The experimental program consists of seven beams with cross section 150*300 mm and effective span 1200 mm. The beams were designed and reinforced to fail in flexure mode. It was noticed that increasing the concrete cover compressive strength enhanced the mode of failure and increased the ultimate load capacity. Also, Using U jacket of CFRP sheets was an effective technique for bonding new concrete cover and old concrete as it enhanced the mode of failure and led to the same ultimate capacity of the beam strengthened by CFRP strips without removing concrete cover. Bonding new concrete cover and old concrete with bonding agent or steel shear connectors was not sufficient to enhance the failure mode or the ultimate load.


Concrete cover de-bonding, CFRP strips, Repairing, Strengthening, Flexure, Corrosion.


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