Characterization of asphalt binder using tackiness properties

Tack measurement is commonly used for the selection of various types of emulsions or tack coat materials during the construction of HMA overlays. Similarly, for uniform coating around the aggregate surface, the tackiness of asphalt binder also plays a vital role and this helps during the selection of modified and unmodified asphalt binder in HMA production. Therefore, the temperature used during HMA production affects the tackiness of the asphalt binder. The objective of this study was to measure the tack properties of conventional and modified asphalt binders, which are subjected to different aging conditions. To identify the tackiness of the asphalt binder, the dynamic shear rheometer (DSR) was used to perform pull-off testing as per ASTM D8189. The energy required for the adhesive/separation behaviour of asphalt binders from the parallel plates was compared and quantified. A significant difference in adhesive forces or normal force (Fn) at different test temperatures was observed. The work/energy required to determine the tackiness of asphalt binder materials with reference to the distance/gap is well related to testing temperature and aging temperatures. Hence, to follow quality control and quality assurance during the selection of binders for the road construction, evaluation of tackiness is also necessary.