Report No.	CP3 (jot this number down to order)
Title	Recycling of Rubber Tires in Asphalt Paving Materials
Authors	Piggott, M.R. & Woodhams, R.T., University of Toronto, Canada
Publisher
Pub. Date	Environmental Protection Service
Pages	62
Keywords
Description	A relatively small proportion of asphaltic bitumen comprises the average road surface in North America, and yet it is sufficient to consume nearly 75% of the more than 60 billion pounds of bitumen sold annually in Canada and the United States. Although this proportion of asphaltic binder is small (about 6%) its function is critical to the performance of the road surface. Despite the effort that has gone into developing better road surfacing materials, the quality of asphalt binders has not improved significantly over the last 5,000 years. It has been known for at least 50 years that the addition of rubber to asphalt will produce markedly superior road surfaces, some of which are still in use since they were first laid. Partly because of cost and partly because of nonconventional paving techniques rubber has been largely ignored as a practical additive except in special cases. Today there is a large accumulation of old tires which if ground into a fine powder can be mixed in a conventional pug mill along with sand, crushed stone and hot asphalt to produce a hot mix which can be applied in the normal manner without any specialized knowledge or techniques. The extra cost of such modification is only 1% of a typical paving contract whereas the advantages include lower maintenance costs and a more durable road surface that is likely to last well into the next century. This report, specially prepared for Environment Canada, is designed to assist civic, provincial and federal authorities in the development of improved road surfacing formulations through the reuse of old tires.
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