EFFECT OF TACK COATS ON INTERLAYER SHEAR BOND OF PAVEMENTS

Abstract

With increasing economical and technical requirements the design and construction of long lasting asphalt pavements is becoming more and more important. Apart from good structural properties of the individual layers, in this context, the interlayer adhesion plays an important, but often neglected, role. In order to achieve a good bond between the different layers tack coats are often used.<br /><br />\nThis paper describes the results of an extensive investigation into the interlayer adhesion of gyratory specimens using a variety of different tack coats. The interlayer adhesion is determined with the Layer-Parallel Direct Shear (LPDS) tester. The behaviour of specimens with and without tack coat on a rough and a smooth surface is compared.<br /><br />\nAnother aspect of this paper is the influence of moisture, heat and water on the mechanism of tack coats.<br /><br />\nFindings clearly indicate that, although the application of tack coats on laboratory specimens does not necessarily result in a better interlayer adhesion, the potential of tack coats regarding heat and water must not be ignored.