Title: Effect of Surface Characteristics of FRP Bars on Bond Behavior in Concrete

Author(s): Sándor Sólyom, Matteo Di Benedetti and György L. Balázs

Publication: Symposium Paper

Volume: 327

Issue:

Appears on pages(s): 41.1-41.20

Keywords: bar diameter; bond; bond strength; concrete strength; FRP; slip; surface profile; test type

DOI: 10.14359/51713362

Date: 11/1/2018

Abstract:
This paper presents an extensive experimental study of the effect that the surface profile has on the bond behavior of FRP bars in concrete. Studied parameters include: concrete strength (~35 MPa (5075 psi) and ~66 MPa (9570 psi)), test type (pull-out, direct tension pull-out and beam pull-out) and surface profile of the FRP bar (helically wrapped, indented, two types of sand coated and two types of helically wrapped and sand coated. For comparison, ribbed steel bars were also used). It was found that the bond strength can vary considerably when different finishing of the same surface profile type are used (e.g., fine and rough sand coating) and that the concrete strength does influence the bond strength even if it is higher than the limit (~30 MPa (4350 psi)) stated in literature. Furthermore, the bond strength results of all FRP bars were consistently higher than those of steel bars. The highest slip value to reach the bond strength was observed for helically wrapped FRP bars, and the lowest for sand coated bars. Finally, the test setup was found to affect the bond strength, while no significant effect of bar diameter was observed in the results.