Study of Basalt Fibers and Graphene Enriched Polymers on Bond Behavior of FRP Bars in Concrete

In this work is investigated the bond behavior of FRP bars considering basalt as a fiber and also cases where graphene is introduced as a polymer filler. Standard FRP bars where glass is used as fiber is tested under the same conditions in order to have a benchmark. Three different temperatures are considered in the tests, including room temperature and a temperature higher than the glass transition of the polymer. At room temperature the effect of concrete strength and the bar diameter on bond is also investigated. The study developed is experimental, through pull-out tests, as well as numerical, through simulations by the Finite Element method. Cases where basalt fibers are associated to helically-wounded surface treatment showed at least 41.7% superior bond behavior among all cases considered with this fiber at room temperature. Studies with graphene were exploratory and limited to only one percentage of addition. However, results suggest that the addition is able to improve behavior of the polyester resin of the matrix at room temperatures by 49% and at higher temperatures bond degradation was 44% smaller when compared with the literature. It was not observed a statistically significant influence of the concrete strength on bond. Diameter influence on bond was mostly linked to surface treatment.