Cantilever and pull-out tests and corresponding FEM models of various dowel bars in airport concrete pavement

Typically, one side of a dowel bar is coated to allow a dowel bar to move freely in a horizontal direction. However, the coating may induce a frictional force at the dowel-concrete interface and, therefore, a critical level of stress can develop in concrete surrounding the dowel bar at the joint that would result in premature cracking. The main objective of this study is to develop a method to reduce the friction at the concrete-dowel interface while maintaining the adequate level of load transfer efficiency. This study investigates the bonding forces between different types of dowel bar and concrete and explores a new type of dowel bar that would provide a sufficient separation between dowel bar and concrete while maintaining an acceptable level of load transfer efficiency. Both laboratory cantilever and pull-out tests were performed on various types of dowel bar embedded in concrete blocks. Finite element modeling of these tests was then performed to verify the laboratory test results. Based on the cantilever and pull-out test results and the finite element analyses of various types of dowel bar, it can be concluded that a carbon steel dowel bar wrapped with a polyethylene sheet would be effective in providing a sufficient level of load transfer efficiency while minimizing the stress at the joint of concrete pavements.