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Bond behaviour of reinforcing bars in cracked concrete


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Authors

Lees, JM 
Morley, CT 

Abstract

Due to the relatively low tensile strength of concrete, cracks are inherent in reinforced concrete structures. A common cause of cracking is the corrosion of internal steel reinforcement, a deterioration process that can affect the bond behaviour and anchorage capacity of reinforcing bars. Corrosion leads to a reduction of the reinforcing bar diameter, the formation of a weak layer of corrosion products around the bar and expansive forces on the surrounding concrete (that can lead to cracking). In the past, the impact of corrosion on bond has been investigated by means of accelerated corrosion tests. However, the more fundamental impact of cracking as distinct from corrosion products on the bond reduction is still not fully understood. This study applies a novel test method to investigate the bond behaviour of reinforcing bars in cylindrical cracked reinforced concrete specimens. The influence of the number of cracks, crack orientation, confinement and concrete cover are investigated. The results indicate a significant loss of bond strength for single cracked specimens. This reduction becomes as high as 65% for double cracked specimens in the absence of confinement. It is shown that the crack orientation with respect to the rib pattern is of minor influence, but the concrete cover and confinement play a significant role in the obtained bond characteristics.

Description

Keywords

Bond strength, Corrosion, Pull-out strength

Journal Title

Construction and Building Materials

Conference Name

Journal ISSN

0950-0618
1879-0526

Volume Title

94

Publisher

Elsevier BV
Sponsorship
Engineering and Physical Sciences Research Council (EP/K016148/1)
Engineering and Physical Sciences Research Council (EP/J002887/1)
The authors would like to gratefully acknowledge the financial support of the UK Engineering and Physical Sciences Research Council (EPSRC) through the EPSRC Project ‘Reinforced concrete half-joint structures: Structural integrity implications of reinforcement detailing and deterioration’ [Grant no. EP/K016148/1].