Loading...
Effects of Epoxy-Coating on the Bond of Reinforcing Steel to Concrete
Hadje-Ghaffari, Hossain ; Darwin, David ; McCabe, Steven L.
Hadje-Ghaffari, Hossain
Darwin, David
McCabe, Steven L.
Citations
Altmetric:
Abstract
The effects of deformation pattern! bar size, concrete cover, casting position, concrete slump 1 consolidation, transverse reinforcement, and concrete strength on the reduction in bond strength between reinforcing bars and concrete caused by epoxy coating are described. Tests include beam-end and splice specimens containing No. 5, No. 6, No. 8, and No. 11 bars. A preliminary investigation of the behavior of epoxy-coated hooks is also described. Epoxy coatings reduce bond strength. In general, this reduction increases with bar size and changes with deformation pattern: bars with a relatively large rib-bearing area are affected less by the coating than bars with a smaller bearing area. The bond strength of both uncoated and coated bars increases as concrete cover increases. The bottom to top-cast bar strength ratio, B/T, increases for uncoated bars and decreases for coated bars as concrete slump increases. Transverse steel increases bond strength; coated confined bars had virtually the same bond strength as uncoated unconfined bars. Design recommendations are made. Analytical studies are conducted on a statical model, consisting of two rigid bodies (steel and concrete) in contact, and a finite element model, representing onehalf of a beam-end specimen. Statical model analyses indicate that 0.35 and 0.10 can be adopted as representative coefficient~ of friction for uncoated and coated bars, respectively. Finite element analyses indicate an increase in bond force will occur with an increase in cover, lead length, or bar size.
Description
Date
1991-07
Journal Title
Journal ISSN
Volume Title
Publisher
University of Kansas Center for Research, Inc.
Research Projects
Organizational Units
Journal Issue
Keywords
Beam-end specimen, Beam-splice specimens, Bond (concrete to steel), Coatings, Coefficient of friction, Cohesion, Deformed reinforcement, Epoxy-coated reinforcement, Fictitious crack model, Fracture mechanics, Nonlinear finite element analysis, Reinforcing steels, Splitting crack, Structural engineering
Citation
Hadje-Ghaffari, H., Darwin, D., and McCabe, S.L., "Effects of Epoxy-Coating on the Bond of Reinforcing Steel to Concrete," SM Report No. 28, Research Grant No. CES-8616228, The National Science Foundation, July 1991, 304 pp.