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Asphalt & Concrete Recycling

Asphalt is the material used to bond aggregate materials together in asphalt concrete or asphalt shingles. Concrete is essentially any aggregate materials bonded together to form road surfaces, curbs, building foundations, etc. Much of the asphalt and concrete in roadway use today is recycled material. Many recycled roadways are recycled while the roadway is being resurfaced for immediate reuse, according to the California Department of Resources Recycling and Recovery (CalRecycle).

  1. Cold In-Place Recycling

    • One method of on-site roadway recycling is cold in-place recycling (CIR), according to the U.S. Department of Transportation (USDOT). CIR removes, grinds and separates 3 to 4 inches of asphalt concrete components before adding asphalt softeners and remixing components. This new mix is then laid over the roadway base left in place, compacted and usually covered with a thin layer of road surface material. CIR saves energy and is used when only road surfaces are damaged.

    Hot In-Place Recycling

    • Another on-site roadway recycling method is hot in-place recycling (HIR), reports CalRecycle. HIR melts and mixes roadway surfaces without removing the surface. Asphalt softeners are added to the mix in the same pass that road surfaces are melted and mixed. The surface is compacted and then a new thin layer of road surface material is usually laid over everything else. HIR uses more energy than CIR, but is essentially just a surface repair as well.

    Full-Depth Reclamation Recycling

    • Full-depth reclamation recycling (FRR) removes the entire asphalt pavement section and a portion of the underlying roadway base, states CalRecycle. The mix is crushed and any additives needed are mixed with it. The mix is then reapplied to the roadway course and compacted before a fresh road surface is laid over it. FRR is usually used when roadways are deemed unfit and need to be completely refinished.

    Hot Recycling

    • Hot recycling involves transporting old roadway surfaces to asphalt and concrete recycling plants. At these plants, removed road surfaces are melted and combined with asphalt softeners and new aggregates, according to CalRecycle. Hot recycling is used when road materials in existence are not an opportune mix and on-site additives will not create an acceptable mix.

    Asphalt Shingles

    • USDOT reports that recycled asphalt roofing shingles are commonly used in the manufacture of recycled roadway surfaces. Shingles are essentially melted and used as a binding agent as with other asphalts for roadway aggregates. This reuse of asphalt shingles keeps tons of roofing waste out of U.S. landfills each year.

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