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asphaltic cement or concrete to produce asphalt or concrete. The
types of material suited for this use include crushed limestone
and dolomite, other quarried rock, and sand and gravel.
Concrete aggregate is aggregate used in the production of
concrete. It is generally made up of washed and graded natural
aggregate deposits or crushed quarry rock, typically occupies 65
to 75 percent of the concrete volume, and influences various
properties of concrete. Most rocks can be used as concrete
aggregate with the exception of rocks containing any appreciable
amounts of shale, soft porous materials, or chert.
Rip rap is a pile of rocks and boulders placed as an erosion
control measure and slope stabilizer to protect slopes, piers,
abutments, walls, or other structures. There are specific size
requirements and gradations for different classes of rip rap.
Rip rap may be any type of durable, field or quarried stone, free
of soil or other debris. In southeastern and central Minnesota,
where limestone is abundant, limestone and dolomite are used for
rip rap. In northern Minnesota, where carbonaceous deposits are
not available, field stone, taconite, and granite are used as rip
rap.
Ballast is a material which is placed on a railroad bed to
provide a stable foundation for the track and ties. Ballast
distributes train loading, drains the roadbed, and resists
deformation of the railbed. Ballast can be any rock of specific
size and gradation where it is durable and resists degradation.
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Last modified: May 25, 2011