The influence of low temperature behaviour of polymer modified binders and of cryogenic tensile stress in asphalt on the life cycle of traffic areas

The low temperature behaviour of bituminous binders can be characterised by tests with the Bending Beam Rheometer. The low temperature behaviour of asphalt can be tested by uniaxial tension tests and cooling tests. In a study carried out in cooperation with the German BP corporation various binders were tested in the Bending Beam Rheometer at different temperatures. Not only binders of the same specification and different provenance were involved in the testing but also binders varying in their specification. Furthermore two kinds of bituminous mixtures (Stone mastic asphalt and Binder course asphalt), each with various binders, were tested on their low temperature behaviour. The correlation between the stiffness S of the binders determined in the Bending Beam Rheometer and the low temperature behaviour of the asphalts is presented. For the evaluation of the data determined in the cooling tests a special software for the design of asphalt traffic areas was used. The influence of the cryogenic tensile stress on the life cycle of different asphalt constructions could be calculated. This proved that performance-based testing makes the assessment of life cycle possible. The found correlation between binder and asphalt properties gives the opportunity to discuss whether the knowledge of the low temperature behaviour of the binder alone allows the estimation of its influence on the life cycle of an asphalt traffic area. For the covering abstract see ITRD E157233