Title: Bond Behavior of Corroded Reinforcement Bars

Author(s): YuBun Auyeung, P. Balaguru, and Lan Chung

Publication: Materials Journal

Volume: 97

Issue: 2

Appears on pages(s): 214-220

Keywords: bond; corrosion; reinforced concretes.

DOI: 10.14359/826

Date: 3/1/2000

Abstract:
Corrosion of reinforcement is an international problem that causes extensive damage to various types of structures. While considerable research has been carried out on measuring the amount of corrosion and methods to slow the progress of corrosion, estimating the strength of structural members with corroded reinforcement has not received sufficient attention. The two main mechanisms for the loss of strength are loss of cross section of reinforcement, and loss of bond between concrete and reinforcement. This paper focuses on the loss of bond strength. Reinforcing bars embedded in concrete were subjected to accelerated corrosion using an external current source. The mass loss of reinforcement varied from 0% for the control to 5.91%. The average compressive strength was 4000 psi (28 MPa). The results indicate that: (1) it is possible to induce predetermined accelerated corrosion by passing external current; (2) low levels of corrosion (less than 1% mass loss) improves bond strength; (3) corrosion levels resulting in more than 1% mass loss lead to reduction in bond strength; (4) slip at failure reduces exponentially with corrosion, even at low levels; and (5) even after excessive corrosion, measurable bond strength exists. The results obtained in this investigation are being used for the evaluation of beam and slab specimens.