Why not rubber roadbeds?

IF the Western world runs on rubber wheels, it might just as well drive on rubber roads. The surface would last longer than conventional macadam and would be less expensive to lay down. The source of all the rubber needed for such a project would be the very wheels that make travel possible for the majority of us; the billions of pounds of rubber (more than 5 billion in the United States alone) in the form of old tires that are discarded by industrial nations each year.

Ed Stark, the research chemist who developed a way to revitalize ``dead'' or used rubber in 1981 so that it can be reused again and again, makes the suggestion in all seriousness. He recognizes that it sounds implausible but insists it is possible. ``We could never use virgin rubber, because we couldn't make enough of it, but there are enough stockpiled tires around to do the job.''

Mr. Stark bases his opinion on the remarkable durability of rubber railroad crossing pads (thick rubber blankets that go between and immediately adjacent to the rails to provide a smooth crossing for auto traffic) that were introduced a little over a decade ago. ``They show virtually no wear after 10 years,'' he says.

A first step toward using rubber surfacing on roads, Stark suggests, would be to use it as bridge decking. ``The road surfaces on bridges are always being repaired,'' he notes, ``and the bridge has to be partly closed for weeks on end while the repairs take place.'' With the rubber decking the holes would be filled in at night and ``the rubber surface rolled out before rush hour the next morning.''

Meanwhile, products made from the recycled rubber that Stark has named Tirecycle litter his office. They range from tiny cross-slit rubber wheels (the ``fingers'' used to pick up paper on photocopying machines) to truck tires that have been retreaded with the product. They include buckets, the standard office waste bin, and a complicated piece of molding that turns out to be a gasoline tank for a riding mower. Most are black, but some are in pastel shades. The technology now exists to make them in almost any color.

Virtually all the products are made with a mix of recycled and new rubber or plastic, but a few are made from 100 percent Tirecycle. They include truck-bed liners and gymnasium exercise mats. The company that makes them, Whirl Air Rubber Products, moved from Ohio to Babbitt, Minn., just to be close to the source of raw material.

Miller Little Giant Manufacturing Company of Minneapolis is using Tirecycle mixed with reinforcing fibers - also recycled from the old tires - to make a range of products, buckets and feeding troughs for the most part, for the agricultural market. The fibers add strength to the final product but do not enhance its looks in any way. But as John Stark, chief operating officer of Rubber Research Elastomerics, puts it: ``Farmers want durability and the pig doesn't care about beauty!''

An eventual possibility would be to make new tires from old, but the Starks believe tire manufacturers will be the last to embrace the product. ``Tirecycle will have to prove itself in all other areas first,'' says John Stark, but he notes that Japanese tire manufacturers are ``expressing interest.''

Ed Stark, on the other hand, points out that there is a lot of potential for Tirecycle in other, less-critical areas of an automobile. ``There's an average of 300 pounds of rubber in every car - after the tires have been removed,'' he points out.