Charlie McDonald

Over 50 year ago, Charlie McDonald, an engineer for the City of Phoenix, developed a time/temperature formula for mixing scrap tire material and asphalt to develop a material that would make the asphalt behave much like tire rubber. His motivation started earlier when he was with the Bureau of Highways (now FHWA) and traveled extensively in State Parks in California, living in a small trailer with a leaky roof and he needed a flexible material to patch and seal the roof so the rather primitive roadways would not continue to cause cracking.

After he joined the City of Phoenix, he continued his experiments, first in his kitchen and later in the engineering laboratory.  When he was satisfied, he had achieved the right formula, he took the material to the street s where he covered potholes.  Application methods were primitive, but the binder he created started a whole new paving industry.

Asphalt-Rubber has been used in forty states in the U.S. and over 25 countries worldwide. Many projects have performed beyond engineering expectations. The reason is that his formula provided a binder with 20% tire rubber contents or higher.

The tire rubber is not dissolved and has been fully saturated in with the oil in asphalt cement. Properly designed asphalt-rubber pavements have lasted fifteen years or more in significantly reduced pavement thickness.