Hot In-place Recycling (HIR) is an on-site, in-place pavement preservation and corrective maintenance technique that when combined with an asphalt overlay can be classified as structural rehabilitation. There are three sub-disciplines of HIR; Surface Recycling, Remixing and Repaving. All HIR sub-disciplines consist of heating, softening, scarifying/hot milling, mixing, placing and compacting the existing pavement. Rejuvenating agents and additives can be integrated into HIR mixtures to improve the characteristics of the recycled pavement. HIR should be considered whenever mill and fill or a leveling course is required prior to an asphalt overlay.
20-40% more cost effective than conventional maintenance/rehabilitation techniques
Reduces greenhouse gases by up to 30%
Reuses 100% of existing materials
Same day return to traffic
Extends pavement life by 7-15 years (dependent on the ability to restore asphalt viscosity and mitigate any existing asphalt mixture deficiencies)
Structural Layer (a) Coefficients between 0.42 and 0.44 (equivalent to agency values for HMA)