Hot In-Place Recycling
Contract-Ready Construction Specification Guidelines
Download GuidelinesLearn about the benefits of Hot In-Place Recycling Treatments
Did you know that cracked and damaged roadways can be reused to create new roadways? Hot In-Place Recycling (HIR) heats the damaged roadway to over 300°F, loosens the surface and then combines the scarified asphalt with a rejuvenating agent (or virgin asphalt) before compacting the mix. The rejuvenated surface can then be overlaid with a new asphalt layer if additional strength is required, or simply sealed with a chip seal, micro surfacing or thin lift asphalt mix. This method helps maintain the structural integrity of the top 2” of roadway while using less material.
HIR can extend the life of a roadway by roughly 7-15 years and is 20 to 40 percent more cost-effective than conventional maintenance/rehabilitation techniques to completely resurface a road. The entire HIR process only takes a few hours, which means it’s not only fast and cost-effective but also easier on the traveling public.
HIR should only be used on pavement that requires a structural upgrade or exhibits large cracks, ruts or loss of friction.
Best Practices
- Sample the roadway prior to operation.
- Identify any existing patching materials present in the roadway.
- Confirm that subgrade issues do not cause pavement distresses. If they do, those issues must be addressed.
- Calibrate prior to undertaking operation.
- Allow the mat to cool prior to allowing traffic onto the new surface.
Pavement Preservation Success
Success Story: Hot In-Place Recycling
DownloadThe Kansas Department of Transportation (KDOT) determined that a 39-mile stretch of road in Ellsworth and Lincoln Counties was in need of pavement preservation. While the existing structure was in good shape, significant cracking and oxidation were present on the surface. The team believed they could improve the surface by using hot in-place recycling (HIR) with a chip seal to serve as a wearing course.