Title: Bond-Slip Mechanisms of Fiber-Reinforced Polymer Fibers Embedded in Cementitious Matrix
Author(s): Mohammed Farooq and Nemkumar Banthia
Publication: Materials Journal
Appears on pages(s): 189-200
Keywords: bond-slip; fiber/matrix bond; fiber-reinforced concrete; fiber-reinforced polymers
The influence of factors such as cementitious matrix characteristics, fiber inclination, and temperature on the interfacial bond between fiber-reinforced polymer (FRP) fibers and cementitious matrix are studied herein. It was noticed that use of glass fibers in the form of glass FRP (GFRP) composite fiber greatly improved the bonding mechanism over using just constituent glass fibers. With matrix maturity, a steady increase in bond was observed with over 60% bond strength achieved within a day. Densification of the cementitious matrix with the addition of silica fume was found to greatly increase the interfacial bond and changed the failure mode from fiber pullout to fiber rupture and delamination. At inclined loading as well, a different failure mode in the form of fiber rupture after partial pullout was noticed. This change in failure mode from fiber pullout to fiber rupture was also accompanied by a lower apparent tensile strength at large inclination. At lower temperature of –20°C, the bond between FRP fibers and the cement matrix was found to improve, but increased brittleness in fibers was also noted. At higher temperatures, FRP fibers performed satisfactorily up to 80°C, after which a gradual degradation in bond was observed.