Schweizerisches Handbuch fuer die Konzeption des Strassenoberbaus. (Manuel suisse de conception des chaussées).

Le présent manuel de conception des chaussées s'adresse aux ingénieurs et aux techniciens oeuvrant dans le domaine de la construction et de l'entretien des chaussées en Suisse. L'ouvrage fournit les outils et conseils nécessaires au dimensionnement d'une chaussée, à la sélection de la structure offrant la solution économique optimale et à la sélection des techniques d'entretien et des matériaux adéquats, compte tenu du trafic, des conditions géométriques, topographiques et environnementales de l'ouvrage concerné. Il contient le savoir-faire d'experts de la construction et de l'entretien des chaussées en Suisse et fournit les informations utiles à la conception et à l'entretien des superstructures routières, qu'elles soient souples, semi- rigides ou en béton, mais ne comprend pas les ouvrages d'art. Il traite également des techniques et des matériaux innovants. Le manuel se veut complémentaire aux normes suisses et aux publications helvétiques en matière de conception et d'entretien des chaussées. Les normes reprises dans ce recueil sont complétées par les considérations pratiques en matière de construction et de maintenance des chaussées, en particulier pour le choix des structures, des techniques d'entretien et des matériaux. Le manuel doit fournir au praticien la solution technique et économique la mieux adaptée compte tenu des conditions locales de l'ouvrage considéré

Mechanical properties of porous asphalt, recommendations for standardization

Porous Asphalt (PA) is used worldwide for its favorable splash and spray properties and its reduction of aquaplaning under rainy conditions as well as its noise reduction properties. Switzerland started using PA in 1979 with mixed results. According to a survey taken in 2004, nine of the 26 cantons use PA. In particular, canton Vaud in western Switzerland is known as one of the leaders in promoting and using PA. Currently, 1/3 of the Vaud motorways are covered with porous asphalt and the use of PA is planned to be extended to most of the motorway surfaces in the canton Vaud up to an altitude of 600m. In addition, there are several bridge trial sections with PA. After the initial survey of the literature appropriate mechanical tests for porous asphalt were chosen (Table 8. 1). At the same time a survey of current experience with porous asphalt in Switzerland was conducted (Appendix 2). Tests were performed on laboratory prepared specimens (AG1, AG4, AG5, VD7, VD8, VD9) and cores (VD2, VD3, VD4, VD5, VS6, AG2, AG3, VD10) taken from selected pavements chosen based on the feedback from various cantons. The behavior of the selected materials was also assessed using an analytical model. Laboratory tests allowed the comparison of core performance with that of laboratory prepared specimen as well as comparison with field performance. Based on the results two mixes were optimized (VD9, AG5) and recommendations for mechanical tests appropriate for porous asphalt were made

Low temperature characterization of bituminous binders with a new cyclic shear cooling (CSC) failure test

Low temperature cracking of asphalt pavements is associated to the thermal stresses created when asphalt binder changes from a ductile into a brittle state during cooling. Under repetitive traffic loads, this change of properties can become a significant problem, resulting in the formations of large cracks on the driving surface, thus requiring early pavement repair. Nevertheless, the conventional test methods for assessing low temperature properties of bitumen are often insufficient and subject to low reproducibility. Therefore, a reliable method is necessary to characterize the performance of bituminous binders at low temperature. This work presents the cyclic shear cooling failure test (CSC-failure test) as an alternative method based on a failure test with the dynamic shear rheometer (DSR) at decreasing temperature until fracture occurs. Operational parameters, like shear strain amplitude or loading frequency, have been analysed in order to develop a reproducible procedure applicable for different types of bituminous binders. Moreover, a failure criterion has been defined by analysing the different characteristic temperatures from the failure curves obtained in the test.</p