Asphalt recycling has become a key component of the Canadian paving industry and it is critical that the appropriate technology is adopted to ensure the desired pavement quality is achieved. The range of cold and hot asphalt recycling procedures (blended granular material, cold plant, full-depth cold processing, cold in-place train with emulsion, hot in-place and hot-mix plant) is reviewed in terms of applicability, limitations and practical experience, with an outline of suggested engineering specification and testing requirements. Production of quality recycled hot mix incorporating a high reclaimed asphalt pavement content requires a consistent processed reclaimed asphalt, appropriate asphalt, appropriate new asphalt cement properties, representative Marshall mix design, proper hot-mix plant operations and quality control/quality assurance to conventional hot mix requirement. For cold or hot in-place asphalt recycling, evaluation of the existing pavement for suitability and selection of appropriate procedures and materials is emphasized. Research needs are identified. These include the investigation of: a) fine manufactured sand for recycled hot mix voids development; b) fatigue and rutting resistance. Experience indicates that asphalt recycling is technically sound, economically favourable and clearly contributes to sustainable development through materials, energy and landfill conservation. (A)
Samenvatting