Asphalt Rubber mixtures in Portugal: practical application and performance

Authors: Mª de Lurdes Antunes, Fátima Batista, Paulo Fonseca



Since 1999, approximately 315 000 tones of asphalt rubber, manufactured by the wet process, have been applied on 24 sites in Portugal, both in new construction and in maintenance and rehabilitation works. Two main types of
asphalt rubber mixtures have been in use, depending on the specific conditions of the job: a) gap graded mixtures, placed in 40 to 60 mm thick layers, as structural overlays and/or as wearing courses and; b) open graded mixtures, placed in 30 to 40 mm thick layers, as wearing courses.
These asphalt rubber mixes have been applied both on flexible pavement structures and on continuous reinforced concrete pavements. During these six years, a good field performance has been observed in general.
Since asphalt rubber applications are still fairly recent in Portugal, some efforts have been put in the determination of performance related properties of this material, with a special emphasis on fatigue and permanent deformation resistance.
This paper highlights some of the main results achieved so far concerning the mechanical characteristics of the AR mixtures, as well as some of the features related to functional characteristics (noise reduction, skid resistance). It also presents some practical recommendations concerning their application in paving works for Portuguese conditions, derived from the experience gathered during the past 6 years.

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