نوع مقاله : علمی - پژوهشی
عنوان مقاله English
نویسندگان English
In this experimental study, the effect of adding macro-polymer fibers (Forta) to concrete at two volume percentages of 0.75% and 1.5% on the bond behavior between concrete and steel in specimens subjected to accelerated corrosion was investigated. To evaluate the behavior, bond stress, rebar slip, and failure modes under the applied corrosion conditions were measured. For this purpose, 30 concrete cubic specimens were prepared and tested. To establish a proper baseline for comparative analysis, three specimens were selected as control samples. The specimens were divided into two main groups: the first group was subjected to varying corrosion levels of 1, 3, and 5%, while the second group, in addition to being exposed to the same corrosion levels, was reinforced with polymer fibers at volume fractions of 0.75% and 1.5%. To evaluate the bond behavior, all specimens were subjected to pull-out tests. The results indicated that with an increase in the corrosion level, the bond strength of the unreinforced specimens decreased by approximately 23% to 43%. Furthermore, intensifying corrosion reduced the rebar slip capacity, shifting the failure mode of the specimens toward a more brittle behavior. Conversely, the addition of macro polymer fibers to the concrete matrix significantly enhanced the bond capacity; under high corrosion levels, the utilization of a 1.5% fiber volume fraction increased the bond strength by 19% to 39% compared to the fiber-free specimens. Additionally, the presence of fibers altered the failure mechanism of the specimens, particularly under severe corrosion conditions (5%), shifting it from a splitting failure to a pull-out failure mode. These findings confirm that Forta fibers can partially restore the degraded bond capacity and improve the ductility of concrete under corrosive effects. The results demonstrated that the presence of fibers improves both the compressive and tensile strengths.
کلیدواژهها English