Dowel load transfer systems for full-depth repairs of jointed Portland cement concrete pavements

A design procedure is proposed for dowel load transfer systems in full-depth repairs of jointed Portland cement concrete pavements. Design traffic levels and joint faulting specifications are input to determine maximum allowable bearing stresses in the dowel load transfer system. Adjustments for various levels of reliability, environmental considerations, and other local factors are also presented. This procedure is based upon analyses of the results of laboratory tests of single dowel systems, measurements of the performance of field installations, and the results of previous laboratory and field studies, as described below.A condition survey of more than 2000 in-service full-depth repairs located throughout the United States was conducted. A model was developed to predict repair joint faulting as a function of traffic loadings, base type, repair age, and climate. Repair faulting and deflection load transfer measurements had been recorded periodically for a group of experimental repairs that featured several load transfer designs. These data indicated a very strong relationship between deflection load transfer and repair faulting; an appropriate model of this relationship was also developed.The laboratory study involved the application of 600,000 or more bidirectional 3000-lb (13.4-kN) shear loads to dowels anchored in holes drilled in concrete specimens. Design and construction variables considered in the factorial test matrix included dowel diameter, drill diameter and impact energy, anchor material, and dowel embedment. A thin nylon disk was placed around each of these dowels at the face of the concrete to retain the anchor material in the drilled hole until it could harden. Tests were also conducted using cast-in-place dowels, hollow stainless steel dowels, and dowels installed in very tight holes. Applied load and dowel deflection data were collected and analyzed to produce models for dowel deflection and looseness, as functions of the load transfer system design variables. The nylon "grout retention disks" were extremely effective in insuring uniform dowel support; their use in field installations should dramatically improve the performance of properly-designed and constructed repairs.U of I OnlyETDs are only available to UIUC Users without author permissio