with even more stunning advancements right around the corner.
It hasn’ t been that long since site preparation was done with a transit and a plumb bob, asphalt removal was accomplished with a walk-behind road saw and operators sat on hot, bodyrattling, smelly machines for hours on end. But it got the job done for decades because it was cutting-edge technology at the time. Small incremental improvements were made over the years, especially after World War II when the Marshall system of mix designs was introduced. As modern traffic continued to put a crushing load on the country’ s roads, intense effort was invested in developing better mix designs.
A new problem emerged in the mid-1970s when the Arab oil embargo led to skyrocketing fuel prices and block-long lines at the gas pump. Household recycling was becoming popular, but the paving industry began to see it as a necessary practice to cut fuel costs. Whereas aged asphalt pavement had been considered waste material and sent to the landfill, reclaimed asphalt paving( RAP) became a valued product, stockpiled and used as an inexpensive road base. During this same time, the cold-milling machine was refined. These highhorsepower asphalt grinders became an integral part of the rehabilitation process. Today, RAP is commonplace, and asphalt pavement is the nation’ s most widely recycled product.
In the early 1980s, the industry tackled a major issue with traditional asphalt paving and binders: rutting. The nation’ s highways were deteriorating to crisis levels. This problem, along with water sensitivity in asphalt mixtures, transverse cracking and aging, led to the formation of the Strategic Transportation Research Study Committee in 1983. After years of development, Superpave, a
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