Once upon a time, old automotive tires were simply consigned to the dump. Now however, thanks to incredible revolutions within the paving industry, such tires are being given a second life as a useful additive in new asphalt. Whether you work in the construction industry, have an upcoming paving project, or are simply a curious amateur, if you would like to learn more about the benefits of this exciting technique, read on. This article will provide a useful overview of the role recycled tires are playing in asphalt production.
The Basic Idea
Before an old tire can be successfully used for asphalt production, it first has to be thoroughly processed. First the entire tire is ground up to produce uniform coarse crumbs. The useful part of the tire is the rubber tread. Yet the ground up tire also contains such extraneous elements as wire and fiber, which are used to reinforce the inner wall of the tire. These elements must be removed before proceeding.
Magnets are utilized to pull the ground up bits of steel wire out of the mixture. Then a specially directed air stream is used to blow out the bits of fiber. The idea here is that, because the fibers weigh less, they can be blown out, leaving only the rubber behind. This crumb rubber is then separated into different sizes and, if necessary, ground down yet further. At that point it is ready to be integrated into a hot asphalt blend.
Classifying The Rubber
The purified rubber product yielded at the end of this process may be known by one of two names: crumb rubber modifier, or CRM, and ground tire rubber, or GTR. These both refer to the same product. Asphalt that has been made using either GTR or CRM is most commonly called rubberized asphalt.
There are two main varieties of rubberized asphalt, which differ mainly in the amount of rubber being integrated. So-called asphalt rubber contains a higher amount of CRM—most commonly somewhere from 18% to 22%. Terminal rubber asphalt, on the other hand, contains a lower proportions of CRM, usually between 10% and 20%. Additionally, terminal rubber asphalt is generally produced using a more finely ground rubber. For most paving projects, either one of these varieties offers an improvement over regular asphalt. Yet if maximizing traction is a high priority, be sure to opt for asphalt rubber. The higher percentage of rubber solids will provide an extra degree of grip, especially when conditions are icy or wet.
Rubberized Asphalt Benefits
Rubberized asphalt is valuable for more than just being a way to recycle unwanted automotive tires. The asphalt itself is structurally superior to that created without CRM. To begin with, rubberized asphalt tends to have a much higher degree of durability, and wears down less quickly than traditional asphalt. Integrating rubber into its structure also acts to minimize roadway noise. Being more porous, rubberized asphalt also retains less heat than traditional asphalt. As noted above, it also provides an extra measure of traction. Opt for rubberized asphalt as way to extend longevity and improve performance and safety.
For more information, contact companies like Asphalt Of Duluth.