Concrete Terms Glossary
Useful item, Online Concrete
Accelerator - Chemical substance added to a concrete mix that reduces the set time by increasing the rate of hydration.
Aggregate - Concrete is a mixture of water, portland cement, and aggregates (sand and/or stone). Sand is considered a fine aggregate, while any stones are coarse aggregates.
Air Entrained - microscopic air bubbles intentionally incorporated in concrete during mixing to
increase durability and resistance against damage by repeat freeze-thaw cycles. Recommended for all exterior concrete.
Bleeding - The emergence of water from newly placed concrete caused by the settlement of solid materials within the concrete.
Bull Float - a tool comprising a large, flat, rectangular piece of wood, aluminum, or magnesium usually 8 inches wide and 48 inches long and a handle 4 to 16 feet in length used to smooth unformed surfaces or freshly placed concrete.
Cubic Yard - Unit of measure for ready mix concrete. Concrete is ordered, sold, and batched by volume.
Curing - The maintenance of the proper moisture and temperature of concrete in its early stages so that desired properties may develop.
Gravel Mix - A concrete mix that utilizes either pea gravel or larger smooth gravel as its coarse aggregate. This mix is typical for exposed aggregate finishes.
Grout - A mixture of cement water and sand. No coarse aggregates (stone) is added to grout.
Limestone Mix - A concrete mix that utilizes a crushed limestone aggregate. This mix is typical for most applications where exposing the aggregate is not desired.
Performance Mix - Specified at the time of ordering in lieu of sack content. This mix is specified to meet a minimum compressive strength requirement (ie. 3000 psi, 3500 psi, 4000 psi). More psi = more strength and durability.
Portland Cement - A hydraulic cement that sets and hardens by chemical interaction with water.
Ready Mixed Concrete - Concrete purchased and delivered in a plastic and unhardened state.
Sack - A quantity of Portland Cement. One sack weighs 94 pounds.
Sack Mix - The amount of sacks of cement in a cubic yard of concrete. Specified when ordering, concrete is typically referred to as 5 sack mix (or 5.5 sack, 6 sack, etc.) The sacks on cement needed in a mix are usually specified in either the plans or the specifications of a project. More sacks = more strength.
Screeding - The operation of forming a surface by the use of a screed or strike-off and screed guides (typically, the forms).
Set Time - A measurement in hours and minutes of the hardening of concrete to resist a measure of penetration.
Slump - a measure of consistency of freshly mixed concrete, measured in inches. It is the distance that freshly mixed concrete subsides when a conical mold (slump cone) is lifted from the test specimen. Increasing the slump is typically done by increasing the batch water. This method also will begin to erode the strength of the concrete if the slump is raised higher than its designed level.
Sub Grade - The prepared and compacted soil made to support a structure or pavement system.
Water Reducer - A chemical admixture that lowers the amount of mix water needed to achieve a desired slump. The use of a water reducer can help achieve a higher strength as well as making the concrete easier to finish.
Volumetric Mixer - A concrete mixer that measures and produces plastic ready mix concrete by volume rather than weight. Volumetric mixers meter their concrete output as they produce the concrete. Also known as continuous batching.