Title: Bond Strength Model of Strand in Corrosion-Induced Cracking Concrete

Author(s): Ju Yi, Lei Wang, and Royce W. Floyd

Publication: Structural Journal

Volume: 117

Issue: 6

Appears on pages(s): 119-132

Keywords: bond strength; confining stress; corrosion pressure; cracking concrete; strand

DOI: 10.14359/51728060

Date: 11/1/2020

Abstract:
This paper presents an analytical model to predict the evolution of strand bond strength with the propagation of concrete corrosion cracking, in which the transition of bond failure modes from pullout failure with strand rotation to concrete splitting failure is considered. For both failure modes, the ultimate bond strength is determined from the contributions of adhesion, corrosion pressure, and maximum confinement by considering the helical characteristics of seven-wire steel strand. The corrosion pressure in the uncracked, partly cracked, and completely cracked stages is estimated based on the relationship between radial displacement and pressure at the strand-concrete interface. For the contribution from maximum confinement, a critical confining stress is applied for the pullout failure type to consider the effect of strand rotation. The predicted results are shown to reasonably reproduce the variation tendency of strand bond strength and experimental results for specimens with and without stirrups. For the pullout failure type with strand rotation, introduction of the critical confining stress limits overestimation of contributions of confinement to the ultimate bond strength, especially for the corroded specimens with stirrups after complete cover cracking.