Hot Process Recycling of Asphalt Pavement Materials--State-Of-The-Art

Continuously increasing costs of roadbuilding materials have generated considerable interest in reclaiming and reprocessing of existing asphalt pavement materials. Reprocessing of this reclaimed asphalt coated material cannot be accomplished with totally conventional asphalt hot mixing equipment without the production of "blue smoke". This paper details several processes used in the industry during the past two years to recycle asphalt pavement without formation of the objectionable smoke using conventional asphalt mixing equipment with some modifications. These processes involve various approaches to heating the reclaimed asphaltic material by blending it with overheated new aggregate and by direct contact with low temperature combustion gases.