ARA Engineers Show Illinois How to Pave Highways with Recycled MaterialsDecember 2011
In Illinois, ARA has been supporting the Illinois State Toll Highway Authority (‘Illinois Tollway’) since 1999. During that time, ARA has provided many traditional highway support services, including: pavement surface and pavement structure evaluation services, pavement and asset management system software implementations and maintenance, pavement materials construction quality database software, roadway maintenance quality assurance, and pavement marking (roadway striping) performance modeling.
And while 'green' and 'environmentally friendly' are the last things most people think of when discussing paving roads, ARA has supported the Illinois Tollway with numerous ‘green initiatives’ over the past five years to include:
- Re-use of deteriorated concrete pavement through in-place rubblization
- Investigation of reflective crack control techniques
- Incorporation of recycled asphalt roofing shingles into asphalt roadway materials
- Ground Tire Rubber (GTR) asphalt pavement demonstration project
- Incorporation of Reclaimed Asphalt Pavement (RAP) as an aggregate and asphalt resource in new asphalt mixtures
- Evaluation of the benefits of fractionating RAP (fRAP) as an aggregate and asphalt resource in new asphalt mixtures
- Evaluation of ‘black rock’ Portland Cement Concrete (PCC) using fRAP as an aggregate substitute in PCC mixtures
- Evaluation of Warm-Mix Asphalt (WMA) material performance as an alternative to Hot-Mix Asphalt (HMA)
ARA's research support for the use of WMA is particularly noteworthy. WMA is a technology developed in Europe that allows the producers of asphalt mix to use a production and paving temperature 30ºF to 80ºF lower than that of traditional HMA. Beyond the fuel consumption of up to one-third less than traditional HMA, the lower working temperature also permits paving at greater distances from the asphalt factory while still including RAP. There are other environmental benefits as well, including reduced asphalt plant emissions of volatile organic compounds (VOC) and greenhouse gases, and also health benefits to the workers, who are exposed to up to 50 percent less aerosols and fumes. While ARA did not develop WMA technology, we continue to be an industry leader in exploring the opportunities presented by WMA and other technologies to improve transportation while making it safer for the transportation workers to install with less of an environmental impact.
The Transportation Infrastructure Division (TID) Champaign, IL, office has provided the vast majority of services for the Illinois Tollway, with additional support from the Mid-Atlantic Division (MAD), and is presently finishing the 2nd year of a three-year contract. ARA looks to continue to work for the Illinois Tollway and other state transportation agencies across the country for many years to come as they face challenges to support mobility of people and goods in a changing economy and world.