Use of Recycled Tire Rubber in HMA Mixtures for Airport Pavements in Colombia

Description

Use of Recycled Tire Rubber in HMA Mixtures for Airport Pavements in Colombia

 Fabio Mendez, Javier Ulloa, Ricardo Carreño

ABSTRACT: The following study highlights Colombia’s research in the use of recycled ground tire rubber (GTR) to modify asphalt mixtures. The specific case of rehabilitation work at Ernesto Cortissoz airport in the city of Barranquilla, Colombia, will be presented.  The airport rehabilitation design recommended laying an asphalt rubber modified HMA unto concrete slabs to act as a transition layer between the existing rigid pavement and the new flexible pavement surface course. The existing airport runway and taxiway structure consists of a deteriorated rigid pavement top layer with more than 40 years in service, with the majority of slabs showing high levels of fatigue deterioration.  The chosen rehabilitation alternative required repairing all affected slabs before placing a flexible pavement structure composed of a 6cm intermediate layer made of asphalt mixture with GTR topped by a 9cm surface layer composed of polymer (SBS) modified HMA.  The recycled tire rubber HMA layer was recommended to mitigate both bottom up crack reflection as well as existing concrete joints crack reflection, throughout the airport’s runway and taxiways.

The advantages of Asphalt Rubber wet process method are shown, which consists in adding GTR to the binder based on its physical and chemical characteristics, complying with Colombian specifications for modified asphalt.  The asphalt mixture design was based on aggregate selection and mixture design according to the Federal Aviation Administration (FAA) specifications, AC 150-5370-10G item P401.  Recommendations are made with regards to producing asphalt mix in an industrial plant and its proper placement in the field.  Finally, the advantages of GTR modified asphalt mixtures with regards to durability of the pavement layer will be presented, to be considered a sustainable alternative for pavement rehabilitation.

KEYWORDS: GTR, asphalt-rubber, rehabilitation, fatigue, durability.