This investigation was undertaken to develop a mechanistic design procedure for selection of tack and prime coat type in relation to traffic loading, pavement temperature and the AC overlay required thickness. The methodology used in this study to compare the performance of different tack and prime coats required the development of a 3-D computer program that takes into account the horizontal shear stresses induced on the pavement surface due to vehicle braking effects (acceleration and deceleration). Taking into account the induced shear loading, the shear stresses at the interface layers were computed. Next, these shear stresses were compared to the bond strength of the tack or prime coat under consideration. This research study provides a methodology and design guide based on mechanistic analysis to select appropriate tack or prime coat for given field conditions. Based on the AC layer thickness a suitable tack or prime coat can be chosen (or vice versa in some cases) to minimize the delamination distress.
