Bond Performance for Corroded and Epoxy-coated Steel, and Glass Fiber Reinforced Polymer Dowel Bars

Abstract: Installing dowel bars at rigid pavement joints provides load transfer to adjacent slabs, and the bond between the dowel bars and the surrounding concrete plays a relevant role. However, the abrasion incurred in the transportation of bars before installation and the development of dowel bar corrosion due to deicing agents can reduce the effectiveness of the load transfer mechanism. Consequently, the hindered performance of the dowel bars can lead to accelerated pavement deterioration. This paper presents the findings from a study involving the accelerated corrosion of dowel bars embedded in concrete and quantifies the effect of corrosion on the dowel bar’s bond behavior through pullout testing. The study uses three dowel bar materials: uncoated carbon steel, epoxy-coated carbon steel, and glass-fiber reinforced polymer. The uncoated steel dowel bars were subjected to accelerated corrosion at different target damage levels, reflecting different in-field deterioration states. Accelerated corrosion was imposed by adding sodium chloride to the concrete mixture with current induction through each specimen in full humidity conditions. For current induction, the dowel bar acted as the anode while stainless-steel mesh cast in the perimeter of the cylinder molds for the specimens acted as the cathode. The setup allowed for design corrosion levels to be established and monitored by applying power supplies. The loading frame used for pullout testing held the specimens using a pin with ends fixed to an actuator inserted into a hole at the end of the dowel bar. As a specimen was raised upward by the dowel bar, the concrete specimen was restrained by the beam of the testing frame, resulting in the pullout of the dowel bar from the specimen. The pullout strength and variation between the pullout force and dowel bar displacement were obtained for the various materials following the AASHTO T 253 procedure. Through the findings of this study, the long-term bonding behavior of steel dowel bars in rigid pavement can be accurately represented in the corroded state and compared with other non-metallic options.