Abstract
Evaluation of Recovered Binders from Swiss LTPP-Sections with Superpave Binder Tests
The results show that the new Superpave binder tests are valuable tools for assessing binders recovered from old pavements but should be further analyzed, for example, by master curves and Black diagrams. It was found that on a large scale basis Superpave binder tests lead to a ranking of recovered bituminous binders similar to conventional tests, especially for warm temperature characteristics. For polymer bitumen binders with a high polymer content completely different results were obtained.
For both conventional and Superpave binder tests, some inconsistencies between bituminous binder properties and pavement performance were found, showing that the binder properties alone do not sufficiently explain the behavior of the whole composite. Hence, a binder selected using a performance based binder classification system has only limited influence on the long term pavement performance and does not replace a proper mixture design.
An advantage of Superpave binder tests is, that fundamental physical properties instead of empirical characteristics are obtained. As conventional tests are often the only link to original pavement data, these tests should still be performed in parallel for LTPP studies.
Finally, it was found that long-term storage may reduce the penetration of recovered binder considerably but does not influence other conventional characteristics such as R&B Softening Point or Fraass breaking point significantly.
For more information, contact Manfred N. Partl.
Swiss Federal Laboratories
Materials Testing and Research
EMPA Section 113
Road Engineering/Sealing Components
Überlandstrasse 129
CH-8600 Dübendorf
Tel. +41-1-82355 11
Fax +41-1-821 62 44