PERFORMANCE RELATED REQUIREMENTS FOR BITUMINOUS BINDERS

摘要

Understanding the behaviour and performance of bituminous binders in asphalt mixtures is a well-researched topic, as performance related specifications are becoming more and more accepted by the bitumen producers as well as by the asphalt industry. The higher axle loads and increasing traffic are elements, which are asking for a right evaluation of the binder to assess the binder contribution in the asphalt performance. The definition of performance indicators and specifications implies as a first step that the performance requirements for the binder are clearly defined. Apart from the production requirements (for pumping and storage), they are of course closely related to the performance requirements of the mix. In this paper, an inventory is made of these necessary requirements. A distinction is made between functional requirements (to ensure the mix its performance on site) and handling requirements (for manufacturing and placing). If one however tries to make an importance ranking of potential binder performance requirements one realises that this is difficult because of the influence of several factors which are not related with the bituminous binder's quality , such as climatic conditions, traffic and special circumstances (e.g. high shear, danger for reflective cracking, etc.). Also economic considerations and political decisions can play an important role in the choice for the a given pavement. In a second step binder related parameters and tests are proposed and discussed for each of these performance requirements. The ranges for these parameters for different types of binders were investigated and the impact on the performance was studied. Based on the available information. One can conclude that reliable performance indicators can be defined for bearing capacity, permanent deformation and low temperature cracking. They are based on classical parameters, such as penetration, and on rheological measurements. Further research is needed in the field of fatigue cracking, thermal cracking, reflective cracking and resistance to ravelling and fretting.