A+B Contract - Concrete placement; Cost-plus-time bidding process where each contractor includes a time cost bid along with their construction bid and the contractor selected has the lowest combined bid total.

AASHO - American Association of State Highway Officials, for the Concrete Industry

AASHTO - American Association of State Highway and Transportation Officials, Concrete Industry

Abrasion - The process of wearing down or rubbing away by means of friction on concrete surfaces.

Absolute Volume (of ingredients of concrete or mortar) - The displacement volume of an ingredient of concrete or mortar; in the case of solids, the volume of the particles themselves, including their permeable or impermeable voids but excluding space between particles; in the case of fluids, the volume which they occupy in concrete.

Absorption - The amount of water absorbed in concrete under specific conditions, usually expressed as a percentage of the dry weight of the material; the process by which the water is absorbed in concrete.

Accelerators: An admixture which, when added to concrete, mortar, or grout, increases the rate of hydration of hydraulic cement, shortens the time of set in concrete, or increases the rate of hardening or strength development.

ACI - American Concrete Institute, For the Concrete Industry

ACPA - American Concrete Pavement Association

ACR - Alkali-Carbonate Reaction usually in Concrete applications

Adhesion - A property of soil which causes the particles to stick together. Necessary for concrete overlays

Adhesion Loss - The loss of bond between a joint sealant material and the concrete joint face noted by physical separation of the sealant from either or both joint faces.

Adhesives - The group of materials used to join or bond similar or dissimilar materials; for example, in concrete work, the epoxy resins.

Admixture: A material other than water, aggregates, or cement that is used as an ingredient of concrete or mortar to control setting and early hardening, workability, or to provide additional cementing properties.

Aggregate - Stone or gravel that was crushed and screened to various sizes for use in concrete, asphalt or road surfaces used in concrete repairs and new concrete placements.

Agitator - A device for maintaining plasticity and preventing segregation of mixed concrete by agitation

Air Content - The amount of air in mortar or concrete, exclusive of pore space in the aggregate particles, usually expressed as a percentage of total volume of mortar or concrete.

Air Void - A space in cement paste, mortar, or concrete filled with air; an entrapped air void is characteristically 1 mm or more in size and irregular in shape; an entrained air void is typically between 10 m and 1 mm in diameter and spherical (or nearly so).

Air-Entraining - The capabilities of a material or process to develop a system of minute bubbles of air in cement paste, mortar, or concrete during mixing.

Air-Entraining Agent - An addition for hydraulic cement or an admixture for concrete or mortar which causes air, usually in small quantity, to be incorporated in the form of minute bubbles in the concrete or mortar during mixing, usually to increase its workability and frost resistance.

Air-Entraining Cement – A cement that has an air-entraining agenda added during the grinding phase of manufacturing to assist concrete durability in cold environments

Air-Entrainment - The inclusion of air in the form of minute bubbles during the mixing of concrete or mortar.

Alkali-Aggregate Reaction - Chemical reaction in mortar or concrete between alkalis (sodium and potassium) released from portland cement or from other sources, and certain compounds present in the aggregates; under certain conditions, harmful expansion of the concrete or mortar may be produced

Alkali-Carbonate Reaction - The reaction between the alkalies (sodium and potassium) in portland cement binder and certain carbonate rocks, particularly calcite dolomite and dolomitic limestones, present in some aggregates; the products of the reaction may cause abnormal expansion and cracking of concrete in service.

Alkali-Silica Reaction [ ASR ]- The reaction between the alkalies (sodium and potassium) in portland cement binder and certain siliceous rocks or minerals, such as opaline chert, strained quartz, and acisic volcanic glass, present in some aggregates; the products of the reaction may cause abnormal expansion and cracking of concrete in service

Amplitude - The total vertical distance the vibrating drum or plate is displaced from a resting or neutral position from the eccentric moment in the concrete industry.

Area of Steel - The cross-sectional area of the reinforcing bars in or for a given concrete cross section.

Articulate - To fit together into a coherent whole; unify for concrete placement.

ASTM - American Society for Testing Materials. Ex; Concrete core sample testing