Dowel-Concrete Contact Characteristics: Analysis, Laboratory Setup, Experiments

Dowel-jointed concrete pavements often show serious cracks long before their design life expires. The most common forms of cracks are mid-slab transverse cracking and transverse joint damage. While dowel-concrete friction forces are the major parameter contributing to such forms of damage, current concrete pavement design procedures are based on the assumption that such forces do not exist. Design specification state that the steel dowels should be coated with bond-breaking fluid that is assumed to fully eliminate dowel-concrete frictional forces. Lack of measured values of dowel-concrete friction coefficient hinders accounting for dowel-concrete axial forces in the design of dowel jointed concrete pavements. In this book, the dowel-pulling force and the dowel-concrete coefficient of friction were measured using a novel laboratory setup of vibrating wire strain gauges embedded in both the dowel and concrete. Theoretical model is developed to enable calculation of the dowel-concrete friction coefficient. A 3D finite element analysis is used to estimate the stress field in the concrete surrounding dowel bars. Results indicate that coefficient of friction is higher in uncoated bars.