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Aggregate

Aggregate

Knife River is built on a foundation of more than 1.2 billion tons of aggregate reserves.
Knife River mines aggregates then adds product value through the production and sale of cement, asphalt, ready-mixed concrete and related products and services. Products from Knife River's companies have helped build U.S. military installations, interstate highways, airports, major sports, business and retail facilities, as well as schools and subdivisions.

Aggregate Facts

According to the National Stone Sand and Gravel Association, about 10 tons of aggregate per person are used annually in America:

  • Every mile of interstate contains 38,000 tons of aggregates
  • 94 percent of asphalt pavement is aggregate
  • 80 percent of concrete is aggregate
  • About 400 tons of aggregates are used in construction of the average home

Aggregate Terms

Aggregate:
any combination of sand, gravel and crushed stone in its natural state
Fine Aggregate:
any material that passes a 3/8 inch sieve, and essentially all of which passes a No. 4 sieve and is predominately retained on the No. 200 sieve.
Coarse Aggregate:
crushed stone or gravel almost all of which is retained on a No. 4 sieve.
Construction Aggregate:
any combination of sand, gravel and/or crushed stone sold to or used by the construction industry.
Crushed Stone:
any hard, sound rock that is produced by blasting and crushing. composed of limestone, granite, traprock or any other hard, sound rock that is produced by blasting and then crushing. Crushed stone is screened to a specific size at the site in stationary or portable plants.
Sand and Gravel:
any clean, unconsolidated mixture of fine and/or coarse aggregates found in a natural deposit.

Source: National Stone Sand & Gravel Association Aggregate Handbook.

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