Cement Dictionary of Terms

Erosion.

Wearing away, as, for example, through the action of water, of the weather, etc.

Failur.

Collapse, rupture, or fracture—as the failure of a beam or column.

Form.

Wooden or metal constructions set up temporarily for the purpose of holding con crete in shape and in place until it has set and has hardened sufficiently to be self-sup porting.

Frost Lin.

The average level to which frost penetrates into the ground. It varies in dif ferent localities.

Fusio.

Melting; usually applied only to melt ing of mineral substances which takes place at relatively high temperatures.

Gauging—Stirring or mixing.

Granolithi.

Consisting of artificial stone of fine granular structure.

Gree.

Unripe, unseasoned, fresh. Applied to concrete, it signifies concrete which has not completely set.

Grou.

Thin mortar.

Gypsu.

A mineral consisting of the hydrous sulphate of calcium—that is, sulphate of lime containing a considerable amount of water of crystallization. When the water is driven off by heat, the resulting product is "plaster of Paris." Hardening—See Setting.

Hydration—A chemical change that takes place in combination with water or under the ac tion of water.

Hydraulic—Active in the presence of, or under the influence of, water. Hydraulic lime and hydraulic cement, for example, are lime and cement that will set and harden under water. Derived from Greek "hudor" (water).

Incipient—Beginning to take place. Burning to "incipient" fusion, for example, means heating to a temperature at which fusion or melting of the material begins.

Keene's Cemen.

A special form of gypsum plaster whose properties depend on an ad mixture of a certain proportion of alum.

Monolit.

A term applied to single-piece work, or walls built with concrete between frames. A word of Greek origin; its literal meaning is "one stone." Mortar—A plastic mixture of lime, cement, plaster of Paris, or other material, with sand, water, hair, etc.; used for plastering or for binding together stone, brick, etc., in con struction work.

Mould.

Frames used to shape concrete, plas ter, or metal into various forms.

Pebble-Stone

Finish—The finish given stucco or plaster work by spreading small pebbles over the surface.

Plaster of

Paris—Anhydrous sulphate of lime. Produced by calcining gypsum at a tempera ture sufficient to drive off the water of crystallization. Mixed with water, it forms a paste which quickly hardens, and is much used for casts, mouldings, hard plaster, stuc co-work, etc. So called because first brought from a suburb of Paris.

Plasti.

Capable of being moulded, formed, modeled, or spread, mortar or paste. Porous—The quality of possessing pores or minute voids.

Rammin.

The pounding or beating of concrete to compress the mass and force out the su perfluous water.

Reinforced or Reinforcin.

To reinforce means to give additional strength to; in concrete work, it signifies the imbedding of steel mem bers in a mass of concrete in such a way as to add to its strength and elasticity.

Retempe.

To stir thoroughly again, so as to give a workable consistency; to regauge, as in stirring up mortar or concrete that has al ready begun to set.

Rubbl.

Rough, broken stone used in coarse masonry, or to fill between the facing courses of walls, or in making up the interior of mas sive stone or concrete work.

Screed.

Levels for guides and bearings for leveling and ruling off.

Setting—Loss of plasticity; solidification from plastic state, due to crystallization of the ce menting material. Takes place soon after mixing. To be distinguished from "harden ing," which may continue for months or years after the "set" is complete.

Siliceous—Containing silica (quartz or sand), or partaking of its nature. Written also "Silicious." Soakage—The absorption of water by hardened concrete, stone, brick, etc.

Soundness—Absence of tendency to cracking, swelling, shrinking, distortion, or disintegra tion under varying conditions of moisture and temperature; constancy of volume.

Stonette—A composition of Portland cement and fine aggregate.

Striking—Taking down and removing—as, for example, striking the centers or forms used in arch construction.

Stucco—Cement mortar or gypsum plaster, used in exterior finishing of buildings.

Subfoundatio.

The first layer of material placed in excavated ground for sidewalks, floors, etc.; usually it is cinders.

Tampin.

The pounding of concrete to reduce voids and force the aggregates as closely to gether as possible into a compact mass.

Tensile Strengt.

The holding power or meas ure of adhesiveness of concrete or cement mortar; power to resist the action of forces tending to pull apart. Contrasted with Com pressive Strength, the power to resist crush ing under direct pressure.

Trap Roc.

A dark-colored igneous rock of great weight and strength, including basalt, feldspar, etc.

Treads and Riser.

The tread is the horizontal part of a step. The riser is the vertical part.

Vitrif.

To make glass-like, as vitrified clay, glazed surfaces, etc.; usually done by heating to fusion.

Void.

The air-spaces or interstices between the particles of aggregates.

Waterproofing—Rendering impervious to mois ture. Accomplished either by special treat ment of the concrete surface, or by mixing special solid or liquid compounds into the concrete mass before placing.

Wearing Surfac.

The top coat of cement and sand on walks, stairs, platforms, or verandas; any surface that is exposed to wear by being walked upon or brought into contact with outside forces.