| 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. |
| Bush-hammer | (Concrete Engineering) A tool having a serrated face, as rows of pyramidal points, used to develop an architectural finish for concrete surfaces. |
| Calcine | (Concrete Engineering) To alter composition or physical state by heating to a specific temperature for a specific length of time. |
| Calcium Aluminate Cement | (Concrete Engineering) The product obtained by pulverizing clinker consisting essentially of hydraulic calcium aluminates resulting from fusing or sintering a suitable proportioned mixture of aluminous and calcareous materials. |
| Carbonation | (Concrete Engineering) 1) Reaction between the products of portland cement (soluble calcium hydroxides), water and carbon dioxide to produce insoluble calcium carbonate (efflorescence). 2) Soft white, chalky surface dusting of freshly placed, unhardened concrete caused by carbon dioxide from unvented heaters or gasoline powered equipment in an enclosed space. 3) Carbonated, dense, impermeable to absorption, top layer of the surface of concrete caused by surface reaction to carbon dioxide. This carbonated layer becomes denser and deeper over a period of time. 4) Reaction with carbon dioxide which produces a slight shrinkage in concrete. Improves chemical stability. Concrete masonry units during manufacturing may be deliberately exposed to carbon dioxide after reaching 80% strength to induce carbonation shrinkage to make the units more dimensionally stable. Future drying shrinkage is reduced by as much as 30%. |