ABRASIVE AGGREGATE  Aggregate used to increase the abrasiveness of the surface of a concrete slab.

ABSOLUTE VOLUME  In concrete, the actual volume occupied by the different ingredients determined by dividing the weight of each ingredient in pounds by its specific gravity, times the weight of one cubic foot of water in pounds.  Example:  Absolute Volume of one sack of cement equals:  94 ÷ (3.15 x 62.4) = 0.478 cubic feet.

ABSORPTION  The process by which water is absorbed.  The amount of water absorbed under specific conditions, usually expressed as percentage of the dry weight of the material.

ABSORPTION LOSS  Water losses that occur until the aggregate in a concrete mix is saturated.

ACCELERATION  The speeding up of the setting or hardening process of concrete by using an additive in the mix. The process of acceleration allows forms to be stripped sooner or floors finished earlier.

ACCELERATORS  Material additives used to accelerate, or reduce, the setting time of concrete causing it to harden faster. Accelerators often include calcium chloride, or aluminum sulfate or other acidic materials.

ADIABATIC CURING  The maintenance of ambient conditions during the setting and hardening of concrete so that heat is neither lost nor gained from the surroundings of the concrete.

ADMIXTURE  A material, other than aggregate, cement, or water, added in small quantities to the mix in order to produce some desired modifications, either to the physical or chemical properties of the mix or of the hardened product. The most common admixtures affect plasticity, air entrainment, and curing time. These admixtures are often referred to as plasticizers, superplasticizers, accelerators, dispersants, and water-reducing agents.

AGGREGATE  A mixture of sand, rock, crushed stone, expanded materials, or particles that typically compose 75% of concrete by volume improve the formation and flow of cement paste and improve the concrete's structural performance.

AGITATING SPEED  The rate at which a concrete or mortar mixer rotates the drum or blades in order to agitate mixed materials to prevent segregation or setting.

AGITATOR TRUCK  Vehicle designed to take pre or ready-mixed concrete and deliver it ready to be used at a construction site.  The truck bed contains a large barrel or drum that is used to continuously roll or agitate the concrete mixture keeping it from solidifying before use.

AIR CONTENT The amount of entrained or entrapped air in concrete or mortar, exclusive of pore space in aggregate particles, usually expressed as a percentage of total volume of concrete or mortar.

AIR-ENTRAINED AGENT  An additive to hydraulic cement or an admixture for concrete or mortar that causes air to be incorporated in the form of minute bubbles on the concrete or mortar during mixing, usually to increase its workability and frost resistance.

AIR-ENTRAINED CONCRETE  A Portland cement with an admixture that causes a controlled quantity of stable, very small air bubbles to form in the concrete during mixing.

AIR METER  A device for measuring the air content of a concrete or mortar mix.

AIR PERMEABILITY TEST  A procedure for determining the fineness of powdered material such as cement.

AIR SLACKING  The absorption of moisture and carbon dioxide from the air by lime or cement.

ALKALI SILICA REACTIVITY  The reaction of aggregates, which contain some form of silica or carbonates with sodium oxides or potassium oxides in cement, particularly in warm, moist climates or environments, causing expansion, cracking or popouts in concrete.

AMERICAN ASSOCIATION OF STATE HIGHWAY AND TRANSPORTATION OFFICIALS (AASHTO)  An organization that represents highway and transportation departments in the 50 states, the District of Columbia and Puerto Rico.

AMERICAN CONCRETE INSTITUTE  An international organization dedicated to providing knowledge and information for the best uses of concrete.

AMERICAN STANDARD OF TESTING MATERIALS (ASTM)  An organization that represents the United States in the International Organization for Standardization (ISO).

ASPHALT  A black petroleum residue, which can be anywhere from solid to semisolid at room temperature. When heated to the temperature of boiling water, it becomes able to be poured. It is used in roofing materials, surfacing roads, in lining the walls of water-retaining structures such as reservoirs and swimming pools, and in the manufacture of floor tiles. Asphalt should not be confused with tar, a similar looking substance made from coal or wood and incompatible with petroleum derivates.

BACKFILL  The replacement of excavated earth into a trench around or against a basement crawl space foundation wall.

BALL TEST  A test to determine the consistency of freshly mixed concrete by measuring the depth of penetration of a cylindrical metal weight or plunger that has been dropped into it.

BALLAST  A layer of coarse stone, gravel, slag, etc., over which concrete is placed.

BAR  A deformed steel member used to reinforce concrete.

BATCH  The quantity produced as the result of one mixing operation, as in a batch of concrete.

BATCH MIXER  A machine that mixes concrete, grout, or mortar in batches in accordance to a design mix. Each batch is used completely before a second batch is started.

BATCH PLANT  A temporary concrete mixing plant usually erected at a jobsite to fulfill the specific needs of that job. They are typically erected when a large volume of concrete will be required at a specific job. Batch plant utilization reduces transportation costs, increases control of the mixture, and speeds up job completion.

BLEEDING  The autogenous flow of mixing water within, or its emergence from, freshly placed concrete or mortar. Bleeding is caused by the settlement of the solid materials within the mass. Bleeding is also called water gain.

BLENDED CEMENT  A hydraulic cement consisting of an intimate and uniform blend of granulated blast-furnace slag and hydrated lime, Portland cement and granulated blast-furnace slag, Portland cement and pozzolano, or Portland-blast-furnace slag, cement, and pozzolano. Blended cement is produced by intergrinding Portland cement clinker with the other materials or by a combination of intergrinding and blending.

BLOCK OUT  The installing of a box or barrier within a foundation wall to prevent the concrete from entering an area. For example, foundation walls are sometimes "blocked" in order for mechanical pipes to pass through the wall, to install a crawl space door, and to depress the concrete at a garage door location.

BOND  The adhesion of cement paste to aggregate and or the rebar.

CAPILLARY SPACE  A term used to describe air bubbles that have become embedded in cement paste.

CAST-IN-PLACE CONCRETE  Concrete that is poured into forms that are erected at the job site. It is the same as the term sitecasting.

CEMENT  A material composed of fine ground powders that hardens when mixed with water. Cement is only one component of concrete. The gray powder that is the "glue" in concrete.

CEMENT CONTENT/CEMENT FACTOR  A quantity of cement contained in a unit volume of concrete or mortar, ordinarily expressed as pounds, barrels, or bags per cubic yard.

CEMENT MIXER  A concrete mixer. A container used to mix concrete ingredients by means of paddles or a rotary motion. The container may be manually or power-operated.

CEMENT SLURRY  A thin, watery cement mixture for pumping or for use as a wash over a surface.

CEMENT-AGGREGATE RATIO  The ratio of cement to aggregate in a mixture, as determined by weight or volume.

CONCRETE  Concrete is a hardened building material created by combining a mineral (which is usually sand, gravel, or crushed stone) a binding agent (natural or synthetic cement), chemical additives, and water. It is an excellent material to be used in road building, bridges, airports, factories, waterways and other construction projects. Concrete is the mixture of Portland cement, sand, gravel, and water used to make garage and basement floors, sidewalks, patios, foundation walls, etc. It is commonly reinforced with steel rods (rebar) or wire screening (mesh).

GROUT  Grout is typically a mixture of hydraulic cement and water, with or without fine aggregate in flowable form it is called grout.

GUNITE  A dry, high pressure air applied concrete mix.

HYDROPHOBIC CONCRETE  Concrete in which water is repelled by making the concrete hydrophobic.  Hydrophobic concrete also meets the standards outlined in the definition of waterproof concrete.

MBDC  MBDC is a product and process design firm dedicated to transforming the design of products, processes, and services worldwide. The firm was founded in 1995 by William McDonough and Michael Braungart to promote and power "the Next Industrial Revolution" through intelligent design.  MBDC employs Cradle to Cradle Design using strategies it calls "eco-effective" (rather than the widely promoted "eco-efficiency") to create products and systems that contribute to economic, social, and environmental prosperity.

SHOTCRETE  A wet, high pressure air applied concrete mix.

STUCCO  Cement mixed with sand and clay is referred to as stucco for exterior use, yet, is called plaster for interior use.

VAPORPROOF CONCRETE  Vaporproof concrete restricts or prevents the passage of water vapor. Waterproof concrete is not necessarily vaporproof but vaporproof concrete is always waterproof.

WATERPROOF CONCRETE  Waterproof concrete is impervious or unaffected by the liquid form of water. It will prevent the penetration of water.