Abstract
This paper examines the microstructure and mechanical property behavior of FRP reinforcement extracted from several FRP-reinforced concrete bridges built more than a decade ago. These include bridges constructed in Missouri and Texas. In particular, the following tests were performed including SEM, FTIR, EDX, glass transition temperature (Tg), and short shear test (SBS). Results from the evaluation demonstrated that the FRP bars are performing at a level with no observed degradation. The paper collects data to study the implications of the current ACI code knockdown factors relative to field-related data.