PERFORMANCE EVALUATION SYSTEM FOR BITUMINOUS BINDERS

Understanding the behaviour and performance of bituminous binders in asphalt mixtures is a well-researched topic. The developments by the US SHRP in the beginning of the 90s and the follow-up in Europe have triggered the interest towards performance related requirements of bituminous binders. The present paper presents the results of a common research project between Nynas and the Belgian Road Research Centre (BRRC) with the objective to draft a tentative "performance evaluation system" for binders. Use was made of a common database of BRRC and Nynas and of literature results. It could be concluded that firstly, 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. The ranges of each of these indicators could be indicated for a large number of paving grade bitumens, as a function of penetration class. The impact of the indicator on the performance could be determined. A realistic number of performance levels as well as a tentative evaluation system could be proposed. Secondly, further research is needed in the field of fatigue cracking, thermal cracking, reflective cracking and resistance to ravelling and fretting. It is concluded that it is too early to define binder performance indicators, mainly because of lack of indicators showing good correlation with field and/or laboratory mix performance. For the covering abstract see ITRD E117423.