Investigation of fiber reinforced polymer (FRP) dowel bars in rigid pavements

This goal of this dissertation is to investigate the mechanical and material properties of fiber reinforced polymer (FRP) dowels for load transfer devices in concrete pavements under various experimental settings, to develop a numerical model to predict the concrete-dowel bar interfacial stress distribution, and finally to make recommendations about using this material in new concrete pavement construction and for dowel bar retrofit.;Laboratory tests were performed to (1) obtain dowel properties such as stiffness and strength before and after environmental conditionings (temperature changes, alkali attack, moisture absorption and ultraviolet radiation), and (2) develop the relationship between stress/strength ratio and FRP dowel bar fatigue life. In addition, accelerated pavement test (APT) data from Heavy Vehicle Simulator test sections were analyzed. Dowel bars made of different materials (epoxy-coated steel, stainless steel, FRP) were employed in APT testing sections and the Load Transfer Efficiency (LTE) for joints doweled with different types of dowel bars are compared. FRP dowel bar long-term behavior was evaluated with respect to both traffic load repetitions and critical environmental conditions. In order to better understand concrete-dowel interaction, a finite element (FE) model was developed. Stress distributions along the concrete-dowel bar interface were obtained, and used to predict the occurrence of single event cracks. In general, numerical results from the FE model agreed with observations from experiments. The dowel bar maximum stress/strength ratios were also compared with the FRP dowel fatigue life---stress/strength ratio relationship developed from the laboratory fatigue tests to estimate the fatigue life of FRP dowel bars. Bearing stresses were analyzed to estimate the long-term performance of the dowels as load transfer devices.