Surface Recycling was the first HIR process developed with its origins in the 1930’s when the first rudimentary machines were introduced. In the late 1970’s and early 1980’s, HIR equipment had a significant transformation resulting in the development of the Repaving and Remixing processes, along with refinements to the Surface Recycling technology and equipment.
Steady improvements to HIR equipment since their initial developments have been made in the areas of increased mixture temperatures, less destructive surface heating, deeper treatment depths, quieter operation, improved air quality and improved precision of control of rejuvenating agents, admixtures and new aggregates. HIR equipment and technology is continually evolving with the use of hot air heating, infrared heating and a mixing drum in lieu of a pugmill being recent innovations. Modern HIR trains have the ability to provide sequential heating with multiple preheater units. The HIR processes are more environmentally friendly than asphalt pavement mill and fill techniques.