Recycled Asphalt Shingle (RAS) Project, Scott County, Iowa


Asphalt recycling

Description

The Scott County Engineer's Office in partnership with the Waste Commission of Scott County has prepared plans to incorporate recycled asphalt shingles (RAS) into the aggregate surfacing along 190th Street between the City of Walcott corporate limits and the end of paving near Y48 (about 3.1 miles).

See a map of the project location.

By incorporating RAS into this aggregate surfaced road, we strive to achieve the following goals:

  • Realize an overall cost savings by comparing before and after costs that include cost of materials, labor and equipment costs associated with maintenance blading, and reduction in loss of aggregates.
  • Reduce asphalt shingle waste going into the landfill.
  • Reduce quantity of virgin aggregates placed on the road surface.
  • Realize a reduction in the frequency of maintenance blading by mitigating wash boarding and potholes.
  • Reduce dust particulate air pollution.

We will construct test sections of varying mixing proportions, pre-mixed vs. mixed on the road, and compacted vs. non-compacted on 190th Street. The test sections are tentatively scheduled to be built May 7–15, 2018. The RAS will be obtained from the Scott Area Landfill and is made from tear-off shingles with one pass through the grinder. Existing road aggregate will be used for mixed on the road sections and virgin aggregate will be used for pre-mixed sections. The aggregate used for the surfacing is Scott County Modified Class D Crushed Stone, which is defined as 100% passing the 1 1/4" sieve, 90-100% passing the 1" sieve, 10-30% passing the No. 8 sieve, 5-12% passing the No. 200 sieve, the abrasion shall not be more than 45%, the mudball maximum is 4%, and the freeze/thaw loss shall not be more than 10%.

Since 2004, the Waste Commission of Scott County has diverted over 60,000 tons of asphalt shingles from the landfill. Most of this tonnage has been ground and used in Hot Mix Asphalt (HMA), however local agencies have begun investigating the use of RAS on aggregate surfaced roads. In 2016, we built four test sections on secondary roads in Scott County and continue to evaluate their performance.

Agenda

8:45 - 9:00 am Sign in, coffee and donuts
9:00 - 9:45 am Presentation and project discussion
10:00 - 11:15 am 190th Street site visit
11:15 - 12:00 pm Optional visit to Scott Area Landfill and/or General Asphalt Construction Company to view pre-mixing operations, if still in operation

Special Note

This open house event will be weather dependent and may be moved to an alternate date if needed.

Who Should Attend?

County engineers, field technicians, waste commission staff, landfill operators, and other interested staff.

Questions?

Please contact Angela Kersten, Scott County Assistant Engineer, 563-326-8640, angela.kersten@scottcountyiowa.com, or Paul Albritton, Iowa LTAP, 515-294-1231, palbritt@iastate.edu.