ASPHALT TECHNOLOGY FOR HOT IN-PLACE SURFACE RECYCLING

The heat reforming process for hot, in-place rehabilitation of deteriorated asphalt pavements consists of a heating system (up to three liquid propane gas infrared preheaters), which can effectively heat to a depth of 50 mm, and a reforming system (reform, remix, and repave options), which can readily improve the pavement quality through rejuvenation or place a new surface course, from very thin to 50 mm in thickness, in one pass. The main asphalt technology aspects of the heat reforming process can be summarized as determining the overall suitability of the aged, cracked, and rutted pavement for processing (must be structurally adequate for instance); testing the existing pavement to determine the necessary rejuvenator application rate (asphalt cement content, recovered penetration/viscosity, etc.); and monitoring the quality of the in-place, hot recycled mix and any new mix during and after processing, including surface tolerance. No problems have been encountered in meeting softening specifications for aged pavements. The heat reforming process has also been extended to effectively treat asphalt pavements with problems such as severe flushing and low in situ air voids. The key requirements for cost-effective, technically sound, hot, in-place rehabilitation are described through heat reforming process project experience and the associated asphalt technology.