Recycled components of Hot Mix Asphalt include reclaimed asphalt pavement from pavement millings, crushed concrete from public works projects, steel slag ??" a by-product from production of steel ??" and reclaimed asphalt shingles from re-roofing houses (pictured). The surfacing mix is under consideration for future Illinois Department of Transportation projects.

The Illinois Department of Transportation (IDOT) plans to build three demonstration sections with environmentally friendly Hot Mix Asphalt (HMA) surfacing, made from recycled materials in an effort to reduce paving costs.

Dubbed "Total Recycle Asphalt," the HMA paving mixture contains more than 97 percent reclaimed and recycled materials. The demonstration projects using Total Recycle Asphalt were on an April 26 letting, and the results should lead to reduced paving costs.

Using Total Recycle Asphalt is expected to produce savings of about 20 percent for IDOT and local agencies using the new mix, compared to similar traditional HMA mixes.

"We recycle and use over a million tons of reclaimed materials on our highways annually as a matter of everyday practice," said Illinois Transportation Secretary Ann Schneider. "We believe Total Recycle Asphalt will take Illinois to a new level of environmental sustainability, and we hope it will inspire others to follow our lead."

The demonstration projects, conducted when a new material or construction method is under consideration, will help the department evaluate the mix, measure the overall cost, and establish its performance over time.

Only a small amount of new liquid asphalt is required in mix production for durability, and no newly mined aggregate was required for the mix. The new liquid asphalt provides a very soft grade of asphalt, effectively countering the hard and aged recycled asphalt from reclaimed pavement and shingles.