| Absorbed Moisture | (Concrete Engineering) Moisture which is mechanically held in a material. In aggregates, that water which is not available to become part of the mixing water is designated "absorbed" water. |
| Adiabatic Curing | (Concrete Engineering) 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. |
| Adsorption Water | (Concrete Engineering) Water held on surfaces in a material by either physical and/or chemical forces. |
| Air Content | (Concrete Engineering) 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 Entraining Agent | (Concrete Engineering) An addition for hydraulic cement, or an admixture for concrete or mortar which entrains air in the form of minute bubbles in the concrete or mortar during mixing. |
| Alkali-Aggregate Reaction | (Concrete Engineering) Older terminology for Alkali-Silica Reactivity (ASR). |
| ASR - Alkali-Silica Reactivity | (Concrete Engineering) 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. |
| Aluminous Cement | (Concrete Engineering) A hydraulic cement in which the principal constituents are calcium aluminates, instead of calcium silicates which comprise the major ingredients of portland cement. (See calcium aluminate cement) |
| Barrel (of cement) | (Concrete Engineering) A unit of weight for cement: 376 Ibs net, equivalent to 4 US bags of portland cement. The designation presently used is tons of cement. |
| Blaine Fineness | (Concrete Engineering) The fineness of granular materials such as cement and pozzolan, expressed as total surface area in square centimeters per gram, determined by the Blaine air-permeability apparatus and procedure. |