Effect of Macro polymeric fibers (Forta) on bond strength behavior of concrete-steel interface under corrosion conditions

نوع: Type: thesis

مقطع: Segment: masters

عنوان: Title: Effect of Macro polymeric fibers (Forta) on bond strength behavior of concrete-steel interface under corrosion conditions

ارائه دهنده: Provider: shiva dalir

اساتید راهنما: Supervisors: Freydoon Rezaie

اساتید مشاور: Advisory Professors:

اساتید ممتحن یا داور: Examining professors or referees: Mahmoud Nili-Mostafa Moghadasi

زمان و تاریخ ارائه: Time and date of presentation: 2024

مکان ارائه: Place of presentation: آمفی تئاتر

چکیده: Abstract: The bond between concrete and steel in reinforced concrete members is one of the most important factors in the proper performance of structures. bond allows for the transfer of stresses between the concrete and steel, enabling the structure to effectively resist applied loads. The bond between concrete and steel in reinforced concrete structures is primarily influenced by two destructive group;environmental and loading factors. Corrosion of steel in reinforced concrete is one such environmental factor. This phenomenon is primarily caused by the deterioration of the passive layer on the steel surface, resulting in a loss of bond. One method of improving bond behavior in the presence of corrosion is the use of fibers. Fibers, by increasing bond strength, tensile strength of concrete, and controlling crack width, significantly contribute to improving bond.This study experimentally evaluated the bond behavior of concrete and steel under corrosion conditions and the role of fiber reinforcement in improving bond strength. A total of 32 cubic specimens with reinforced with in central bar, and 12 concrete beams with dimensions of 180 mm height, 100 mm width, and 850 mm length were produced. Both cross-sections were reinforced with a 14 mm diameter rebar bond length of five bar diameters. To improve bond behavior under corrosion conditions, two volume percentages of 0.75% and 1.5% Macro polymeric fibers were used in the specimens. Samples were subjected to corrosion at three different concentrations of 1%, 3%, and 5% by applying a steady electrical current to the reinforcing bar immersed in a 5% saltwater solution. Cubic specimens were subjected to a pull-out test to evaluate bond behavior, while beams were subjected to a flexural bond test. Parameters evaluated included bond stress-slip, bond strength, maximum relative slip, failure pattern, and bond toughness.The use of fibers in the concrete mix resulted in increased bond strength and maximum relative slip, mitigating the adverse effects of corrosion on these parameters. Additionally, Macro polymeric fibers improved the failure pattern and increased the energy absorption capacity of the concrete. However, test results indicated that the actual corrosion rate of the specimens was lower than the value predicted by Faraday's law.