| TERM |
DEFINITION |
| asphalt |
Asphalt is a tar-like, petroleum
material, which becomes a liquid at high temperatures. When it
is at room temperature, it is solid. Asphalt can exist naturally
or can be produced as a by-product of petroleum refining.
|
| base
|
The base of a roadway is a mixture
of crushed rock.
|
| boulders
|
Large pieces of rock, often rounded,
and are larger than
12 inches in diameter.
|
| cement
|
A powder made
from a combination of alumina, silica, lime, iron oxide and magnesium
oxide that have been burned together in a kiln. It is used as a
binding agent in concrete. |
| cobbles
|
Cobbles are similar to boulders.
The sizes range from about 3 to 12 inches in diameter.
|
| compaction
|
Reduction
of pore space between individual particles. |
| composition
|
Materials of
which the earth is made. |
| concrete
|
A mass of
sand and rock bound together by cement. |
| clay
|
Clays are
very small, flat materials. Clays range in diameter from about 1/13,000
to 1/200,000 of an inch. Clays typically have low to medium strength
and density, and low to very low permeability. |
| density
|
The weight
of a known volume of material. |
| deposition
|
The accumulation
of earth materials in any given place. |
| dragline
|
An excavating
machine in which the bucket is attached by cables and operates by
being dragged toward the machine. |
| dredging
|
To dig, gather
or pull out materials out of a body of water. |
| embankment
|
A raised structure
to hold back water or to carry a roadway. |
| engineering
properties |
The composition
and depositional environments of earth materials control their engineering
properties, which include strength, density, permeability and particle
size. |
| extraction
tests |
Tests remove
the asphalt portion of an asphalt paving sample to verify that the
correct amount of asphalt was used in the paving material. |
| fail
|
Means the
materials tested did not meet the minimum requirements for the desired
usage. |
| glacial till
|
Glacial till
is a mixture of boulders, gravel, sand, silt and clay deposited
by glaciers. These deposits are usually very dense and compacted
because at one time glaciers were sitting on top of them. |
| granular
|
Consisting
of aggregate pieces. |
| gravel
|
Gravels are
broken pieces of larger rocks and are often rounded. Gravels range
in size from between 1/10 of an inch to 3 inches diameter. Gravels
can vary in density, have high strength if confined in a small space,
and have very high permeability. |
| gravel pits
|
Deposits of
glacial or river rocks that are mined for economic purposes. |
| gypsum
|
A widely used
mineral consisting of hydrous calcium sulfate. |
| hot mix asphalt |
Mixing hot
asphalt with coarse and fine-size rocks makes hot mix asphalt.
These three materials are mixed very well to make sure that the
rocks are evenly distributed in the mix. Each rock piece must be
completely coated by the asphalt. |
| Iowa Pore
Index |
A test done
to measure the amount of water that can be forced into the pore
system of a rock. This measurement directly ties into the rocks’
ability to release water. The quicker the water is released, the
less susceptible a rock will be to breaking or failing due to the
effects from freezing and thawing. |
| loess
|
A fine, wind-carried
material mainly composed of silt with some clay. |
| particle
size |
Measurement
of the size of the individual particles that make up a material. |
| pavement
|
The pavement
is the material on top of the roadway. |
| permeability
|
Measurement
of the ability of water to pass through a pavement material. |
| petroleum
|
A naturally
occurring oily, flammable bituminous liquid. |
| pit lake |
The lake from which gravels are removed
for use in construction.
|
| pore system
|
The mostly
microscopic holes forming a network through which water moves through
a rock. |
| portland
cement concrete |
A hardened
mixture of portland cement, water, rock and sand used in pavements
and structures. |
| quarry
|
An open excavation
for obtaining building stone - like limestone and dolomite. |
| revetment
|
Large aggregate
materials used for erosion control in high-energy environments. |
| sand
|
Sands are
granular earth materials. Sands can be rounded or angular. Sands
range in diameter from about 1/10 to 1/300 of an inch. Sands usually
have medium to high density, medium to high strength if confined
in a small space, and relatively high permeability. |
| silt
|
Silts are
also granular earth materials and are similar to sand. Silts range
in diameter from about 1/300 to 1/13,000 of an inch. They usually
have low to medium density and strength, and medium permeability. |
| strength
|
The ability
to withstand a stress without permanent deformation. |
| subdrain
|
A perforated
plastic pipe placed approximately 40 feet below the surface of the
shoulder of a road. Drains into a ditch by the roadway. |
| subgrade
|
The subgrade
of a roadway is made of soils that have been specially prepared
to meet the requirements to support the other two layers. |
| topsoil
|
The uppermost
layer of soil containing much organic material. This is the layer
crops and other plants are grown in. |
| uniform
|
Consistent,
equal distribution; i.e., uniform blend of materials. |
| volume
|
The amount of space
a substance occupies in three dimensions, i.e.
Volume of rectangle - Length X Width
X Height
|
