Surface-Dependent Interfacial Characteristics of Glass Fiber-Reinforced Polymer Bars in Concrete
Yail J. Kim and Ali Alatify
Appears on pages(s):
bond; fiber-reinforced polymer (FRP); interface; mode of failure; reinforcement; surface characteristics
This paper presents the interfacial behavior of glass fiberreinforced polymer (GFRP) reinforcement embedded in concrete with variable surface geometries. The configurational properties of the reinforcing bars involve a relative rib area of 0.012 to 0.093 and a crest-depth ratio of 4.5 to 50. A total of 90 specimens are tested to establish a relationship between the load-carrying capacity and topographical attributes of the interface for shearing and splitting failure modes. On the basis of multiscale image analysis, the influence of the rib arrangement is accounted for. The interfacial capacity increases with the enlarged relative rib area, while an opposite tendency is noticed with the crest-depth ratio. The load-displacement response and energy dissipation of the
interface are dominated by the surface deformations. Contrary to the shearing failure associated with a local sliding path, the splitting failure results in radial cracking as a function of the relative rib area. The topographical characteristics of the failed interface articulate that the adjusted rib depth is responsible for the distribution and coalescence of concrete residues on the reinforcing bars, which are related to the degree of interaction against the substrate. Furthermore, the critical failure plane of the interface is identified through surface texture measurements. Analytical modeling determines a bursting force for the GFRP reinforcement, different from that of conventional steel reinforcing bars, and assesses the sensitivity
of constituting parameters. In conjunction with probability
distributions and complexity theory, the functional compliance of the model is evaluated and its applicable range is suggested.