Title:
Experimental Evaluation of Factors Affecting Monotonic and Fatigue Behavior of Fiber-Reinforced Polymer-to-Concrete Bond in Reinforced Concrete Beams
Author(s):
Kent A. Harries, Benjamin Reeve, and Andrew Zorn
Publication:
Structural Journal
Volume:
104
Issue:
6
Appears on pages(s):
667-674
Keywords:
adhesive; beam; bond; carbon fiber-reinforced polymer; fatigue; flexural strength; reinforced concrete
DOI:
10.14359/18948
Date:
11/1/2007
Abstract:
An experimental study of a number of factors believed to affect the performance of carbon fiber-reinforced polymer (CFRP)-to-concrete bond is presented. Bending tests on 18 moderate scale beams, measuring 254 x 152 x 4875 mm (10 x 6 x 192 in.), are presented. Two samples were tested as unreinforced control specimens and 16 were fiber-reinforced polymer (FRP) reinforced to exhibit flexure-induced intermediate crack (FIC) debonding. Of these, eight were tested monotonically to failure, whereas the other eight were subject to fatigue loads sufficient to result in fatigue failure of unretrofitted beams in approximately 500,000 cycles. In each series, two different epoxy adhesive systems were used whose moduli varied by a factor of approximately 2. Four CFRP strip geometries were tested to assess the effect of the ratio of FRP width-to-concrete soffit width (the so-called bf/b ratio). Finally, in one comparison, the behavior of a single 50 mm (2 in.) wide strip is contrasted to that of two 25 mm (0.078 to 1 in.) wide strips spaced at 75 mm (3 in.). The effects of each of these parameters—bf /b, multiple strip arrangements, and adhesive modulus—on the monotonic and fatigue performance of the retrofitted concrete beams are presented and discussed.