<title>Recycling of manufactured waste shingles in asphalt paving mixes</title>

Abstract

About 20,000 tons of manufactured waste asphalt shingles are being deposited in landfill every year in the state of Massachusetts. This has caused a shortage of precious landfill space, and significant increase in deposit fee. There is a need to evaluate the use of these waste shingles in hot mix asphalt, specially because the shingles contain significant amount of asphalt binder, and studies in some states have shown that use of shingles can result in savings, and improve hot mix asphalt performance. A laboratory study was conducted by the Worcester Polytechnic Institute and University of Massachusetts at Dartmouth, with a research grant from the Chelsea Center for Recycling and Economic Development. The results show that volumetric and low temperature property of hot mix asphalt with 3, 5 and 7 percent shingles are not significantly different from the properties of conventional hot mix asphalt used for surface courses. Standard deviation of test results for mixes with shingles are low, indicating consistency in the quality of the shingles. Mixes with 5 and 7 % shingles show significantly lower rutting potential compared to mix without any shingles. Hence, it seems that mixes with small amounts of shingles have the potential of savings as well as good performance. However, before any material can be used regularly, it must be evaluated under real-life production and construction conditions.