Durability Assessment of FRP Bars Extracted from Existing FRP Bridge Structures Exposed to Field Conditions

Since the late 1990\u27s there have been a number of bridges in the United States that have been built or rehabilitated using FRP materials. A number of these projects occurred within the state of Missouri between 1999 and 2012. To assess durability behavior of existing bridges, some samples with reinforcing bar including GFRP bars are extracted from several older FRP bridges like Southview Bridge in varying climates to examine their performance after a decade or more under field conditions. This paper presents several analytical methods like Short Bar Shear (SBS) test, Glass Transition Temperature (Tg) test, and Resin Content Measurement [Burn off testing (i.e. resin)] for FRP rebars, and PH Measurement for concrete to evaluate the both physical and chemical properties of GFRP bars and concrete with time under field environmental conditions. This paper is intended to provide a possible path forward to collect important field data on FRP reinforced structures with a view to create a database of field data to better understand the long-term behavior of FRP bars used in the field