Glossary1
Air Void Distribution
Air voids are incorporated in the cement-paste phase of concrete to provide space into which the water can flow as it expands on freezing, thereby reducing the possibility of internal stressing and cracking. The size and distribution of these voids to allow minimal distance between any water molecule and the nearest air void are the parameters that determine the resistance of the concrete to freeze/thaw cracking.
Aggregate
Granular material (e.g., sand, stone, gravel, crushed stone, or iron blast-furnace slag) that is used with a cementing medium to form hydraulic-cement concrete or mortar (see ASTM C125-94).
Agglomerate
Small particles bonded together into an integral mass.
Bleeding
Settling of solid particles in concrete with a concurrent increase in proportion of mixing water at the surface.
Clinker
Nodular manufactured product that is ground to produce cement powder.
Cement Paste
Viscous paste and hardened product of a mixture of cement powder and water.
Concrete
A composite material that consists essentially of a binding medium in which are embedded particles or fragments of aggregate; in a hydraulic-cement concrete, the binder is formed from a mixture of hydraulic cement and water (see ASTM-C125-94).
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Definitions compiled from various sources. Where appropriate, an ASTM Standard is cited. |
Cover
Layer of concrete covering a reinforcement.
Fly Ash
Finely divided residue that results from the combustion of ground or powdered coal.
High-Range Water Reducer
Surfactants that allow a workable mix to be produced at low w/c ratios.
Law of Mixtures
The property, P, of a composite mixture of materials A and B is equal to the sum of the values of that property for each component multiplied by the volume fraction of the component: Pcomposite = PAVA + PBVB.
Model-Based Design
Method of designing new materials, structures, and systems quantitatively rather than intuitively, using all pertinent information simultaneously and synergistically.
Mortar
A product of the mixture of cement powder, water, and sand that is used to bond large blocks (e.g., bricks, cement blocks).
Portland Cement
A hydraulic cement produced by pulverizing clinker consisting essentially of hydraulic calcium silicates and usually containing one or more of the forms of calcium sulfate as an interground addition (see ASTM 150-95).
Pozzolans
Siliceous and aluminous materials that possess little or no cementitious value in themselves but that will—in finely divided form and in the presence of moisture—chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties (e.g., fly ash, silica fume, rice husk ash, volcanic ash).
Rebar
Steel bars used to reinforce concrete.
Slump
A measure of the workability of fresh concrete, determined by tamping the concrete into a cone, removing the cone, and measuring the decrease in height of the concrete mass.
Stucco
A plaster of any composition used to coat the outside walls of buildings.
Thixotropy
The prospensity of gels to become fluid when disturbed.
