| 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. |
| Blast Furnace Slag | (Concrete Engineering) A non-metallic waste product developed in the manufacture of pig iron, consisting basically of a mixture of lime, silica and alumina, the same oxides that make up portland cement, but not in the same proportions or forms. It is used both in the manufacture of portland blast furnace slag cement and as an aggregate for lightweight concrete. |
| Bleeding, Bleed Water | (Concrete Engineering) A form of segregation in which some of the water in a mix tends to rise to the surface of freshly placed concrete. Known also as water gain. |