SIC 2951 Asphalt Paving Mixtures and Blocks
SIC 2951
This category describes companies principally employed in manufacturing asphalt and tar paving mixtures and blocks made of asphalt mixed with other materials.
324121
Asphalt Paving Mixture and Block Manufacturing
In 2005, the asphalt paving mixture and block manufacturing industry shipped $8.28 billion worth of goods, an increase from $7.10 billion in 2002. The industry employed 14,544 workers in 2005, down from 15,725 in 2002. In the mid-2000s, some 1,300 establishments were engaged in the manufacture of asphalt paving mixture and blocks; the states with the most such companies were California, New York, and Ohio. The industry was continuing to see growth in the mid-2000s.
Asphalt is a blackish-brown material with a consistency ranging from a viscous liquid to a glassy solid. Most asphalt is obtained as a by-product of the distillation of petroleum or other materials. Natural asphalt, rarely used by the 2000s, is formed during the early stages of the breakdown of organic marine deposits into petroleum.
Asphalt is used most often in the construction of roads, parking lots, walkways, and other paved surfaces. Of the 2.27 million miles of paved road in the United States, 94 percent of them are surfaced with asphalt, including 65 percent of the interstate system. With the passage of the Transportation Efficiency Act, those figures are expected to increase substantially by 2010.
The primary advantages of asphalt over concrete are cost, flexibility, and durability. Because it softens when heated and is comparatively elastic, asphalt offers a high degree of adaptability in construction applications. Its physical properties also make it less susceptible than concrete to cracking and weathering; it is also more resistant to the salts and chemicals used to clear and maintain roads in inclement weather. Furthermore, asphalt is easier to remove and costs much less than either concrete or natural paving materials. Finally, asphalt is 100 percent recyclable. An entire road surface, for instance, can be excavated and remixed for use in new surfaces.
The main asphalt paving product is hot mix asphalt (HMA), in which asphalt cement is used to bind a mixture of stone, sand, and gravel. Organizations involved in this industry were the National Asphalt Pavement Association (NAPA) of Lanham, Maryland, and the Asphalt Institute's National Asphalt Training Center II in Lexington, Kentucky.
Historic uses of asphalt date back to 3000 B.C., when natural asphalt was used to seal a reservoir at Mohenjo-Daro, Pakistan; it was later used throughout the...
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