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Commercial Asphalt Co.
Frequently Asked Questions
Q: What is asphalt?
Asphalt, also known as hot mix asphalt (HMA), is made from dried crushed
rock and asphalt cement, which is a mixture of petroleum compounds produced by
oil refineries. Known uses for asphalt go as far back as six thousand years.
Archaeologists have established that asphalt is one of the oldest adhesives
known to man. It was used to make bathing pools, reservoirs, and canals
watertight. Asphalt was used in Mesopotamia. Bricks for the great wall of
Babylon were joined with asphalt. Joints of ships were sealed with asphalt. The
Bible story of Noah's ark claims that Noah used pitch, another name for asphalt,
to waterproof the joints in the ark. Asphalt was even used in Egypt to embalm
mummies.
The advent of the automobile required hard road surfaces. After 1918, when
the number of cars and trucks began to increase rapidly, asphalt was taken from
asphalt pits and used for road surfaces. However, most of the asphalt used today
is made from crude oil.
Surfaces of 90% of all paved roads in the U.S. are asphalt because asphalt
is economical and durable, can be constructed and repaired quickly, and provides
riding comfort. Asphalt cement for roads is a mixture of asphalt and crushed
stone, gravel, or sand. Asphalt is also used in varnishes, lacquers, and inks,
waterproofing and insulation materials, floor tiles and it is used to line
storage ponds, dams, and irrigation canals.
Q: How is asphalt made?
Asphalt cement is heated and combined with crushed rock. The asphalt is
then mixed and loaded immediately onto trucks for delivery to construction sites
or kept in storage silos.
Q: What makes asphalt pavement so safe for driving?
Safety is largely a function of maintaining tire contact with the pavement
surface and skid resistance of the surfacing. Asphalt has microtexture, which
aids in skid resistance. Asphalt roads also are quieter than concrete roads
because they don't have expansion joints to create noise. Other safety features
of asphalt:
Asphalt is impervious to de-icing salts and chemicals and is unaffected by
winter road safety maintenance. Asphalt pavements can be designed so that water
drains through the surface layer of the pavement, thus reducing splash and tire
spray, and increasing tire-road contact during wet weather.
Q: Is asphalt environmentally sound?
Yes! Asphalt pavement is 100 percent recyclable and can be made to perform
better the second or even third time around. In fact, it is the most recycled
product in the United States at 80 percent. That compares to significantly lower
percentages for aluminum cans, newsprint, plastic and glass beverage containers,
and magazines. Asphalt roads are removed, recrushed, mixed with additional
aggregate and fresh asphalt cement, remixed and placed back on the road. The hot
mix asphalt industry also accepts the following recycled materials: rubber from
used tires; slag from the steel-making process; roofing shingles; and sand from
metal-casting foundries.
In a report to Congress, the Federal Highway Administration estimated that
over 70 million tons of asphalt paving material was recycled in 1992. Recycling
roads not only conserves natural resources and decreases construction time, it
saves American taxpayers over $300 million each year.
Source: National Asphalt Pavement Association
Commercial Asphalt Co.
P.O. Box 1480
Maple Grove, MN 55311-6480
Phone: (763) 424-5400
Fax: (763) 425-7153
General Inquiry: Webmaster
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