Effect of Bitumen Emulsion as Tack Coat on the Performance of Double-layered Asphalt Samples

Tack coat is applied to prevent deteriorations (slippage, fatigue cracking, de-bonding) on pavement due to weak bonding of asphalt pavement layers. In this study, double-layered asphalt samples were prepared under laboratory conditions, using a C60B2-3 bitumen emulsion and 50/70 asphalt binder as tack coat at the interface between binder and wearing courses. Indirect tensile strengths, tensile strength ratios and interfacial bond strengths of double-layered asphalt samples containing tack coat were determined. After construction of binder course, dusty material was collected from pavement surface to investigate effect of dust on tack coat formed when pavement was opened to traffic for a certain period. The performance of double-layered asphalt layers containing tack coat was investigated in terms of tack coat materials, application ratios of tack coat materials and cleanliness conditions. Also, moisture susceptibility of double-layered asphalt samples containing tack coat exposed to 1, 3, 6 and 9 freeze – thaw cycles was investigated. The originality of the study is to investigate properties of double-layered asphalt samples prepared with tack coat at different tack coat ratios under laboratory conditions.