Title: Comparability of bond tests for repair and retrofit of concrete structures with Fiber Reinforced Concrete

Author(s): Zanotti, C.; Randl, N.; Gar, P.S.; Far, B.K.; Steiner, M.

Publication: Symposium Paper

Volume: 343

Issue:

Appears on pages(s): 381-390

Keywords: Bond test, Repair, Bond strength, Shear bond, Tensile bond, Adhesion, Friction, Fiber reinforced concrete, High strength concrete, Roughness

DOI:

Date: 10/1/2020

Abstract:
Fiber Reinforced Concrete (FRC) is being increasingly applied in structural repair and retrofit of reinforced concrete structures. Not only fiber reinforcement improves the durability of reinforced concrete structures, but it also enhances compatibility of the repair material to the existing structure, further enhancing structural effectiveness and service life of the intervention. Furthermore, studies have shown that fiber reinforcement can significantly improve substrate-repair bond in both tension and shear. However, this benefit is not fully utilized in repair/retrofit design due to test uncertainties and lack of comprehensive data on correlations with other fundamental factors. In this study, the question of the appropriateness, reliability and sensitivity of current bond tests in case of FRC repairs is addressed. Several tension and shear bond tests on plain and fiber reinforced cement-based repairs are performed in parallel by two research teams at UBC (Canada) and CUAS (Austria), following a rigorous testing procedure to allow consistency among results from the two laboratories. The influence of repair strength and casting direction is also investigated. The effect of fiber reinforcement on bond is assessed while correlation, comparability, and sensitivity of different test set-ups and stress conditions are discussed.