Experimental characterization of the pullout and gap opening behavior of misaligned dowel bars under thermal expansion

This thesis focuses on studying experimentally the fundamental pullout behavior of misaligned dowel bars and gap-opening behavior of pavement joints with misaligned dowel bars in plain concrete slabs, under thermal expansion. The variables considered in the experimental plan include the number of dowel bars (1, 2, 3, and 5) and number misaligned (all or alternate), misalignment type (horizontal, vertical, and combined), orientation (uniform and non-uniform) and magnitude (0, ¼, ½, ¾, 1, and 2 in. over half-length (9 in.) of the dowel bar). The effects of these parameters on the bond stress between the dowel-concrete, load induced at different joint openings, and joint and slab distresses (spalling, cracking, non-uniform joint opening, and uplift) were studied.; The initial slip/debonding stress found to be in the range of 10--50 psi irrespective of the misalignment type and magnitude. Within a misalignment type, the load and intensity of distresses increases with an increase in the misalignment magnitude and number of dowels misaligned. Non-uniform orientation of misalignment of two dowel bars requires more load per dowel bar at a given joint opening as compared to the uniform orientation of dowels in the horizontal and combined misalignment types. For a given misalignment magnitude, the overall trend of load versus type of misalignment (horizontal, vertical and combined) is unclear. The load versus joint opening behaviors obtained through this study can be used for development of analytical models to obtain the stress states in dowel-concrete bond behavior subjected to pullout.