Title: Effect of Corrosion on Bond Strength and Development Length of Reinforcing Bar in Epoxy-Grouted Nut Coupler
Author(s): Naseeruddin Haris and Sangeeta Gadve
Publication: Materials Journal
Appears on pages(s): 239-250
Keywords: corrosion; coupler bond strength; development length; epoxy; impressed current; nut coupler; pullout test; reinforcing bar
Corrosion of steel reinforcing bars in reinforced concrete (RC)
structures is a matter of concern among practicing engineers and researchers are perpetually working over it. The development length of reinforcing bars at joints of RC structural frames are more prone to severe corrosion. Due to this, the design stress that needs to be developed in reinforcing bars is largely reduced. In addition, the development lengths of reinforcing bars create congestion at frame joints. This paper is an attempt to overcome these issues. In this paper, an epoxy-grouted nut coupler system is proposed that generates the required design stress in reinforcing bars with a very short development length at end anchorages, due to which congestion of the reinforcing bar at the joints can be avoided. The experimental investigation on the effect of corrosion on bond strength and development length of reinforcing bar in this epoxy-grouted nut coupler is also carried out by performing pullout tests. Statistical models are developed to predict the bond strength between the coupler and reinforcing bar corroded to different levels. This epoxy-grouted nut coupler is an effective tool for developing required stress in reinforcing bars by reducing the actual development length of reinforcing bars in the case of new structures. It is also useful and convenient in regeneration of stress in reinforcing bars at end anchorages that has been lost in corrosion-damaged structures.