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Moxie International - concrete terms Category: Architecture and Buildings > Cement and concrete terms Date & country: 21/08/2008, USA Words: 180

Cement Gel
The colloidal gel (glue like) material that makes up the major portion of the porous mass of which hydrated cement paste is composed.

Cement Content
A quantity of cement contained in a unit volume of concrete or mortar, ordinarily expressed as pounds, barrels, or bags per cubic yard.

Cement, Portland (ASTM C150)
 A powdery substance made by burning, at a high temperature, a mixture of clay and limestone producing lumps called `clinkers” which are ground into a fine powder consisting of hydraulic calcium silicates.  For non-portland cements, see aluminous cement.

Cellular Concrete
A lightweight product consisting of portland cement, cement-pozzolan, cement sand, lime-pozzolan, or lime-sand pastes, or pastes containing blends of these ingredients and having a homogenous void or cell structure, attained with gas forming chemicals or foaming agents. For cellular concretes, containing binder ingredients other than or in addition to portland cement, autoclave curing is usually e...

Carbonation
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 ...

Capillary
Space In cement paste, any space not occupied by anhydrous cement or cement gel.  Air bubbles, whether entrained or entrapped, are not considered as part of the cement paste.

Capillarity
A wick-like action whereby a liquid will migrate vertically through material, in a upward direction; as oil in a lamp travels upward through the wick,

Calcium Aluminate Cement
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.

Calcine
To alter composition or physical state by heating to a specific temperature for a specific length of time.

Calcareous
Containing calcium carbonate or, less generally, containing the element calcium.

Bush-hammer
A tool having a serrated face, as rows of pyramidal points, used to develop an architectural finish for concrete surfaces.

Bond Adhesion
of concrete or mortar to reinforcement, or to other surfaces.  The adhesion of cement paste to aggregate.

Bleed Water
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.

Blast Furnace Slag
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.

Blaine Fineness
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.

Barrel (of cement)
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.

Bag
(See Sack)

Autoclave
A chamber in which an environment of steam and high pressure is produced.  Used in curing of concrete products and in the testing of hydraulic cement for soundness.

ASR
Alkali-Silica Reactivity 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
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)

Alkali-Aggregate Reaction
Older terminology for Alkali-Silica Reactivity (ASR).

Air Entraining Agent
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.

Adsorption Water
  Water held on surfaces in a material by either physical and/or chemical forces. 

Air Content
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.

Admixture
A material other than water, aggregates, and portland cement that is used as an ingredient of concrete, and is added to the batch immediately before or during the mixing operation.

Adiabatic Curing
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.

Accelerator
An admixture which, when added to concrete, mortar, or grout, increases the rate of hydration of the hydraulic cement, shortens the time of set and increases the rate of hardening or strength development,

Absorption
The process by which water is absorbed.  The amount of water absorbed under specific conditions, usually expressed as percentage of the dry weight of the material.

Absorbed Moisture
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.

Absolute Volume
The volume of an ingredient in its solid state, without voids between individual pieces or particles, in the case of fluids, the cubic content occupied. In concrete, the actual volume occupied by the different ingredients determined by dividing the weight of each ingredient pounds, by ifs specific gravity, times the weight of one cubic foot of water in pounds. Example: Absolute Volume of one sack ...

Abrasion Resistance
  Resistance of a surface of being worn away by friction or rubbing process.

AAC
Autoclaved Aerated Concrete  Exceptionally lightweight precast concrete with high thermal qualities and fire resistence.  Suitable for cutting with ordinary hand tools.  Mix design is composed of portland cement, sand or siliceous material, lime, gypsum, finely powdered aluminum, and water.  Initial mix is a combination of portland cement, sand, lime and gypsum to produce a slurry.  Finely powdere...

Tilt-up
A method of concrete construction such as where members are cast horizontally near their eventual position, usually on a recently placed slab,  and then tilted into place after removal of forms.

Thermal Expansion
Change in unit length per degree change of temperature.

Temperature Rise
  The increase of concrete temperature caused by heat of hydration and heat from other sources.

Temperature Reinforcement
  Reinforcement used to carry temperature stresses. 

Temper
The addition of water to the cement mix whether at the batch plant, during transit or at the jobsite to achieve the specified water to cement ratio.

Tamping rod
A round, straight steel rod, 5/8' in diameter and approximately 24' in length, having the tamping end rounded into a hemispherical tip, the diameter of which is 5/8'.

Sulfate Resistance
Ability of cement paste, aggregate, or mixtures thereof to withstand sulfate attack. 

Surface Moisture
Free moisture retained on the surfaces of aggregate particles which becomes part of the mixing water in the concrete mix;

Sulfate Attack
Deleterious chemical and/or physical re-action between sulfates in ground water or soil and certain constituents in cement, which result in expansion and disruption of the concrete.

Specific Gravity
The ratio of the weight of a material at a stated temperature to the weight of the same volume of gas-free distilled water at a stated temperature.

Stucco
A portland cement mortar material that can  be applied to the surface of any building or structure to form a hard and durable covering for the exterior wails or other exterior surfaces.

Slurry
A mixture of water and such finely divided materials, such as portland cement, slag, or soil in suspension.

Spall
A fragment, usually of flaky shape, detached from a larger mass by pressure, expansion from within the larger mass, a blow, or by the action of weather.

Slump Cone
A metal mold in the form of a truncated cone with a top diameter of 4”, a bottom diameter of 8”, and a height of 12”, used to fabricate the specimen for a slump test.

Slump
A measure of the consistency of plastic concrete relative to the amount it falls when a slump cone filled with concrete is lifted vertically.  The slump cone is then placed beside the specimen of concrete and the number of inches from the top of the cone to the top of the of specimen of concrete is the slump. (see ASTM C143).

Slip Form
A form which is raised or pulled as concrete is placed; may move vertically to form wails, stacks, bins or  silos, usually of uniform cross section from bottom to top; or a generally horizontal direction to lay concrete evenly for highways, on slopes and inverts of canals, tunnels,  and siphons.

Sieve
See 'Screen'

Sieve Analysis
Determination of the proportions of particles of The granular material lying within certain size ranges on sieves of different size openings.

Shotcrete
Mortar or concrete conveyed through a hose and projected pneumatically at high velocity onto a surface; dry-mix shotcrete (gunite), and wet-mix shotcrete.

Setting Time
The time required for a specimen of cement paste, mortar or concrete, prepared and tested under standardized conditions to attain a specified degree of rigidity with particular reference to initial and final setting time.

Set
A term used to describe the stiffening of cement paste; a condition reached by a concrete, cement paste, or mortar when plasticity is lost to an arbitrary degree, usually measured in terms of resistance to penetration or deformation. (Initial set refers to first stiffening. Final set refers to attainment of significant rigidity.)

Segregation
The tendency for the coarse particles to separate from the finer particles in handling. In concrete, the coarse aggregate and drier material remains behind and the mortar and wetter material flows ahead. This also occurs in a vertical direction when wet concrete is over vibrated or dropped vertically into the forms, the mortar and wetter material rising to the top.  In aggregate, the coarse partic...

Screen
A metallic sheet or plate, woven wire cloth, or similar device, with regularly spaced openings of uniform size, mounted in a suitable frame or holder for use in separating material according to size.

Scaling
The breaking away of a hardened concrete surface, usually to a depth off/IS' to 3/16'.

Saponification
The deposit of a gray scum or gray dust on the inside surface of a subgrade wall or floor; as the result of moisture moving through the concrete and washing certain chemicals from the concrete mass.

Sand Blast
A system of abrading a surface such as concrete by a stream of sand, or other abrasive, ejected from a nozzle at high speed by water and/or compressed air.

Sand
That portion of an aggregate passing the No. 4 (4.76 mm) sieve and predominantly retained on the No. 200 (74 micron) sieve.

Sacking
Removing or alleviating defects on a concrete surface by applying a mixture of sand and cement to the moistened surface and rubbing with a coarse material such as burlap.

Sack
A quantity of cement: 94 Ibs. in the United States, 87.5 Ibs. in Canada, for portland or air entraining portland cement, or as indicated on the sack for other kinds of cement.

Rock Pocket
Area or portion of hardened concrete which is deficient in mortar and consisting primarily of coarse aggregate and open voids; caused by insufficient consolidation or separation during placement, or both; by leakage from form.

Revibration
Delayed vibration of concrete that has already been placed and consolidated. Most effective when done at the latest time a running vibrator will sink of its own weight into the concrete and make it plastic and workable again.

Yield
The amount of concrete produced by a given combination of materials, the total weight of ingredients divided by the unit weight of the freshly mixed concrete; also, The cubic test of concrete produced per sack of cement; also, the number of product units, such as block, produced per batch of concrete or sack of cement.

Wetting Agent
A substance capable of lowering the surface tension of liquids, facilitating the wetting of solid surfaces and permitting the penetration of liquids into the capillaries.

Workability
The ease with which a given set of  materials can be mixed into concrete and subsequently handled, transported, placed and finished with a minimum loss of homogeneity.

Water Vapor Pressure
The pressure exerted by water vapor.  Air that contains higher amounts of water vapor exerts a higher vapor pressure than air which has a lower amount of  has a higher water vapor pressure In concrete water vapor pressure is calculated by the difference between the vapor pressure of the concrete and the ambient relative humidity and temperature and  in contact with the soil.  that is calculated by...

Waterproof
A material or surface that is impervious or unaffected by water in its liquid form.will repel water in it's liquid form but may not necessarily be vaporproof.

Water-Cement Ratio
The ratio of the amount of water, exclusive of that absorbed by the aggregates, to the amount of cement in a concrete mix.  Typically expressed as percentage of water, by weight in pounds, to the total weight of portland cement, fly ash, and any other cementitious material, per cubic yard, exclusive of any aggregates.

Wagner Fineness
The fineness of materials such as portland cement expressed as total surface area in centimeters per gram as determined by the Wagner turbidimeter apparatus and procedure.

Vicat Apparatus
A penetration device used to determine the setting characteristics of hydraulic cements.

Vibration
Energetic agitation of concrete to assist in its consolidation, produced by mechanical oscillating devices at moderately high frequencies.

Vaporproof
A material that is totally immune to the passage of a gas under pressure. Any material that is truly vaporproof will inherently be waterproof.

Vapor
  When a liquid changes to a gaseous form. The ability of the gas to hold moisture will reduce as temperatures reduce; more moisture can be contained in the gas as the temperatures increase.

Vapor Pressure
The pressure exerted by a vapor that is calculated based upon relative humidity and temperature. The higher the humidity and higher temperature, in degrees Fahrenheit, the greater the vapor pressure exerted.

Unit Water Content
The quantity of water per unit volume of freshly mixed concrete, often expressed as gallons or pounds per cubic yard. This is the quantity of water on which the water cement ratio is based, and does not include water absorbed by the aggregate

Truck Mixer
A concrete mixer capable of mixing concrete in transit when mounted on a truck chassis.

Ultimate Strength
The maximum resistance to loads that a structure or member is capable of developing before failure occurs, or, with reference to cross sections of members, the largest axial force, shear or moment a structural concrete cross section will support.

Tremie
A pipe through which concrete may be placed under water, having at its upper end a hopper for filling, and a bale which permits handling of the assembly by a derrick.

Transit-Mixed Concrete
Concrete produced from a central-batching plant, where the materials are proportioned and placed in truck-mixers for mixing enroute to the job or after arrival there.