HEATING METHOD AND APPARATUS FOR HEAT SOFTENING ASPHALT SURFACE LAYER

摘要

This invention provides a heating method and apparatus in which an asphalt surface layer, for example, in the repair of existing pavements and a road reformation method is heat softened by forming a high-temperature combustion gas layer free from an uneven temperature profile in the asphalt surface layer in its heating region. This method comprises the step of generating a high-temperature combustion gas by a high-temperature combustion gas generation part provided with air blowing means. The method further comprises the step of evenly supplying a high-temperature combustion gas into each of ducts having a circular shape in section. The ducts comprise arcuate radiation faces having a plurality of nozzle holes which face the asphalt surface. The ducts are juxtaposed at given intervals in a gridiron form in the longitudinal direction of movement to constitute a storage part. The storage part is provided above the asphalt surface. The air blowing means evenly supplies the high-temperature gas into the ducts through a central duct provided in the storage part in communication with the high-temperature combustion gas generating part. The method further comprises the step of allowing the high-temperature combustion gas, radiated through the plurality of nozzle holes by the air blowing means, to always form a high-temperature combustion gas layer having a substantially constant temperature on the asphalt surface by a hood having a face open to the asphalt surface so as to cover the storage part. For the plurality of nozzle holes, the distance from the asphalt surface, configuration, and size are properly selected so that a high-temperature combustion gas layer having a substantially constant temperature is always formed on the asphalt surface.