Coefficient of Thermal Expansion and Contraction

The fractional change in length of a material for a unit change in temperature.

Cofferdam

A barrier built in the water so as to form an enclosure from which the water is pumped to permit free access to the area within.

Cohesionless

A material that does not readily bond with other particles.

Cohesionless Soils (Noncohesive Soils)

Earth materials containing less than 20 percent soil particles passing the #200 sieve. Any free-running soil, such as sand or gravel, whose strength depends on friction between particles.

Cohesive Soil

Earth materials containing 20 percent or more soil particles passing the #200 sieve.