Roads & Bridges April 2011
By Kris Beatty and Michelle Caulfield, Contributing Editors
Road construction is a more than $80 billion annual industry in the U.S. Over the last decade, the industry has been driving toward greener and more sustainable design, construction, use and maintenance. New technologies, new materials and new practices all play an important role in reducing the environmental impacts and maximizing economic and social benefits of our nation’s roadways.
The use of recycled materials in hot-mix asphalt (HMA) in road construction has long been an important green strategy of the asphalt-paving industry. Reclaimed asphalt pavement (RAP) is one of the most widely recycled materials in the U.S., with much of this material going into the construction of new roadways.
Recently, the use of recycled asphalt shingles (RAS) in paving has gained significant momentum. RAS can be derived from tear-off shingles from re-roofing projects or from manufacturers’ scrap. Currently 21 states and two Canadian provinces have specifications or procedures in place for using RAS in HMA (all allow manufacturers’ scrap and 11 states allow tear-off roofing shingles).