EVALUATION OF MECHANICAL TESTS FOR POLYMER-BITUMEN

Polymer-bitumen are increasingly used for high performance road and sealing constructions to facilitate construction techniques and to improve long term performance in terms of mechanical, chemo-physical resistance and aging properties. The broad range of applications, the high modern quality standards and the great variety of different products require a thorough and critical review of traditional binder test methods and an open mind to adopt new fundamental tests, like those developed by SHRP (Strategic Highway Research Program, USA). In this study six different polymer-bitumen were investigated and characterized with respect to their mechanical and technical properties to evaluate different test methods. Test methods include traditional binder tests as well as the forced vibration co-axial shear test (FVAST), developed by EMPA, and tests from the SHRP program, such as the dynamic shear rheometer (DSR) and the bending beam rheometer (BBR). Some of the tests were performed on material after aging in the pressure aging vessel (PAV). To back-up the assessment of the results high pressure gel permeation chromatography (GPC) was used. The results show the amount of ranking of the different materials by the different test methods and the influence of different test temperatures. In particular it shows that the FVAST, DSR and BBR are appropriate tools to determine mechanical properties of polymer-bitumen within a wide range of service temperatures and that PAV aging conditions as proposed by SHRP are still to be optimized for this type of material. (A) For the covering abstract see IRRD 885061.