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

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 in pounds, by ifs specific gravity, times the weight of one cubic foot of water in pounds. Example: Absolute Volume of one sack of cement equals: 94 ÷ (3.15X62.4) = 0.478 cubic feet

Absorbed Moisture Moisture which is mechanically held in a material. In aggregates, water that is not available to become part of the mixing water is designated "absorbed" water.

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.

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.

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.

Admixture A material other than water, aggregates, and Portland cement that is used as an ingredient of concrete, and is added to the batch in small doses immediately before or during the mixing operation to produce some desired modifications, either to the physical or chemical properties of the mix or of the hardened product. The most common admixtures affect plasticity, air entrainment, and curing time.

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. A controlled air content prevents concrete from cracking during the freeze/thaw cycle

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 usually to increase its workability and frost resistance.

Air Permeability Test A procedure for determining the fineness of powdered material such as cement.

Alkali-Silica Reactivity - ASR 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.

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.

Anchor Bolts Steel bolts used to secure a wooden sill plate to concrete, masonry floor, or wall.

Angle Float/Trowel A trowel with two surfaces meeting at right angles. An angle float is used for finishing plaster or concrete in an inside corner.

Asphalt Expansion Joint Premolded felt or fiberboard impregnated with asphalt and used extensively as an expansion joint for cast-in-place concrete.

Autoclaved Aerated Concrete - AAC Exceptionally lightweight precast concrete with high thermal qualities and fire resistance, suitable for cutting with ordinary hand tools. The mix design is composed of Portland cement, sand or siliceous material, lime, gypsum, finely powdered aluminum, and water. The finely powdered aluminum reacts with the alkaline components of the cement and lime to produce hydrogen gas, which increases the volume approximately five times producing a uniformly, dispersed cellular structure. Units are cut to required shape and placed in an autoclave, an enclosed pressurized chamber, and steam cured at 350 0 F. Approximately 80% of the ultimate volume consists of air voids.

Backfill The replacement of excavated earth into a trench around or against a basement crawl space foundation wall.

Bag A quantity of Portland cement; 94 pounds in the United States, 87.5 pounds in Canada, 112 pounds in the United Kingdom, and 50 kilograms in most other countries. Different weights per bag are commonly used for other types of cement.

Ball Test A test to determine the consistency of freshly mixed concrete by measuring the depth of penetration of a cylindrical metal weight or plunger that has been dropped into it.

Bar Support (Bar Chair) A rigid device of formed wire, plastic, or concrete, used to support or hold reinforcing bars in proper position during concrete operations.

Barrel A unit of weight measure for Portland cement, equivalent to four bags or 376 pounds.

Batch The quantity produced as the result of one mixing operation, as in a batch of concrete.

Batch Box A container of known volume used to measure the constituents of concrete or mortar in proper proportions.

Batch Plant A temporary concrete mixing plant usually erected at a jobsite to fulfill the specific needs of that job. They are typically erected when a large volume of concrete will be required at a specific job. Batch plants can reduce transportation costs, increase control of the mixture, and speed up job completion.

Batter A slope, such as that of the outer side of a wall, that is wider at the bottom than at the top. The measurement of batter is the horizontal distance between the top and bottom of a slope.

Binder Almost any cementing material, either hydrated cement or a product of cement or lime and reactive siliceous materials. The kinds of cement and the curing conditions determine the general type of binder formed. Any material, such as asphalt or resin, that forms the matrix of concretes, mortars, and sanded grouts.

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.

Blaine Test A method for determining the fineness of cement or other material based on the permeability to air of a sample prepared under specified conditions.

Blanket Insulation sandwiched between sheets of fabric, plaster, or paper facing, used for protecting fresh concrete during curing.

Bleeding, 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. Bleeding is caused by the settlement of the solid materials within the mass. Bleeding is also called water gain.

Blended Cement A hydraulic cement consisting of a uniform blend of any of the following: granulated blast-furnace slag and hydrated lime; Portland cement and granulated blast-furnace slag; Portland cement and pozzolano; or Portland cement, blast-furnace slag, and pozzolano. Blended cement is produced by intergrinding Portland cement clinker with the other materials or by a combination of intergrinding and blending.

Blowhole In concrete, a bug hole or small regular or irregular cavity, not exceeding 15 mm in diameter, resulting from entrapment of air bubbles in the surface of formed concrete during placement and compaction.

Blowout Term used when the ready-mixed concrete breaks through the forming boards due to insufficient bracing. Also, the localized buckling or breaking up of rigid pavement as a result of excessive longitudinal pressure.

Blowup Slang term used to describe the unexpected fast setting of concrete that does not allow proper finishing.

Board Foot The basic unit of measurement for lumber. One board foot is equal to a 1" thick board, 12" in width and 1' in length. Therefore, a 10' long, 12" wide, and 1" thick piece contains 10 board feet. Nominal sizes are assumed when calculating board feet.

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

Bull Float A board of wood, aluminum, or magnesium mounted on a pole and used to spread and smooth freshly placed, horizontal concrete surfaces. After screeding, the first stage in the final finish of concrete, smoothes and levels hills and voids left after screeding. Sometimes substituted for darbying.

Burlap Material often used to protect newly finished concrete from rain as well as maintaining moisture in a slab.

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Caisson The structural support for a type of foundation wall, porch, patio, monopost, or other structure. A 10" or 12" diameter hole drilled into the earth and embedded into bedrock 3 to 4 feet. Two or more "sticks" of reinforcing bars (rebar) are inserted into and run the full length of the hole and then concrete is poured into the caisson hole. A caisson is designed to rest on an underlying stratum of rock or satisfactory soil and is used when unsatisfactory soil exists.

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

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

Calcite The main raw material used in the manufacture of Portland cement. Calcite is a crystallized form of calcium carbonate and is the principal component in limestone, chalk, and marble.

Calcium Aluminate Cement A combination of calcium carbonate and aluminates that have been thermally fused or sintered and ground to make cement.

Calcium Chloride An additive used in ready-mix to accelerate the curing, usually used during damp conditions.

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

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.

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.

Casting Pouring a liquid material, or slurry, like concrete, into a mold or form whose physical form it will take on as it solidifies.

Casting Bed A permanent, fixed form, in which permanent pre-cast concrete forms are produced..

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.

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

Cementitious Having cement-like, cementing, or bonding type properties. Material or substance producing bonding properties or cement-like materials.

Cement Slurry A thin, watery cement mixture for pumping or for use as a wash over a surface.

Central Plant A facility that makes and distributes ready-mix or pre-mixed concrete loading the material into agitator trucks.

Chair(s) In concrete formwork, a small metal or plastic support for the reinforcing steel.The support is used to maintain proper positioning during concrete placement.

Cinder Block A masonry block made of crushed cinders and Portland cement. This type of block is lighter and has a higher insulating value than concrete. Because moisture causes deterioration of cinder block, it is used primarily for interior rather than exterior walls.

Clinker The resulting admixture from burning a combination of limestone with silica, alumina, and iron oxide-containing materials. A lump or ball of the fused material, usually 1/8" to 1" in diameter, is formed by heating cement slurry in a kiln. Clinker, when cool, is ground into a fine powder and interground with gypsum to form cement.

Coarse Aggregate Naturally occurring, processed or manufactured, inorganic particles in prescribed gradation or size range, the smallest size of which will be retained on the No. 4 (4.76 mm) sieve.

Cold Joint A visible line which forms when the placement of concrete is delayed. The concrete in place hardens prior to the next placement of concrete against it.

Colloidal A gel-like mass which does not allow the transfer of ions

Compaction The elimination of voids in construction materials, as in concrete, plaster, or soil, by vibration, tamping, rolling, or some other method or combination of methods. The process of eliminating voids in the non-set concrete mixture that has been placed often using various vibration devices.

Composite Construction Any element in which concrete and steel, other than reinforcing bars, work as a single structural unit.

Compressive Strength The measured resistance of a concrete or mortar specimen to axial loading expressed as pounds per square inch (psi) of cross-sectional area. The maximum compressive stress which Portland cement, concrete, or grout is capable of sustaining.

Concrete A composite material which consists essentially of a binding medium, within which are embedded particles or fragments of a relatively inert filler. In Portland cement concrete, the binder is a mixture of Portland cement and any additional cementitious materials such as fly ash, and water. The filler may be any of a wide variety of natural or artificial fine and coarse aggregates, and in some instances, an admixture.

Concrete Block A concrete masonry unit, most often hollow, that is larger than a brick.

Concrete Contraction The shrinkage of concrete that occurs as it cures and dries.

Concrete Finish A description of the smoothness, texture, or hardness of a concrete surface.

Concrete Finishing Machine A portable machine with large paddles like fan blades used to float and finish concrete floors and slabs. A large power-driven machine mounted on wheels that ride on steel pavement forms. These machines are used to finish concrete pavements

Concrete Masonry Unit A block of hardened concrete, with or without hollow cores, designed to be laid in the same manner as a brick or stone. A CMU is also referred to as a concrete block.

Concrete Mixture The percentage of cement content contained in the concrete. A rich mixture contains a high proportion of cement. A lean mixture is a mixture of concrete or mortar with a relatively low cement content. A harsh mixture of concrete is one without mortar or aggregate fines, resulting in an undesirable consistency and workability.

Condensation When a moisture laden gas comes in contact with a cooler surface a change of state from gaseous to liquid occurs.

Consistency The degree of plasticity of fresh concrete or mortar. The normal measure of consistency is slump for concrete and flow for mortar.

Consolidation Compaction usually accomplished by vibration of newly placed concrete to mold it within form shapes and around embedded parts and reinforcement, and to eliminate voids other than entrained air.

Construction Joint A horizontal or vertical joint formed when placement of concrete is interrupted for some reason, usually the end of a day’s work. A 'surface' is formed as the placed concrete cures, and then fresh, plastic concrete is poured against this surface at some later point in time.

Control Joint Tooled, straight grooves made on concrete floors to "control" where the concrete should crack.

Cream Construction slang term to describe the cement and sand component of ready-mix that rises when the aggregate is worked down by way of agitation – floating, troweling, screeding, etc.

Cure Method of maintaining sufficient internal humidity and proper temperature for freshly placed concrete to assure proper hydration of the cement, and proper hardening of the concrete.

Curing Blanket A layer of straw, burlap, sawdust, or other suitable material placed over fresh concrete and moistened to help maintain humidity and temperature for proper hydration

Curing Compound A chemical applied to the surface of fresh concrete to minimize the loss of moisture during the first stages of setting and hardening.

Curing Membrane Any of several kinds of sheet material or spray-on coatings used to temporarily retard the evaporation of water from the exposed surface of fresh concrete, thus ensuring a proper cure.

Cut and Fill A term used to describe the addition or subtraction from a grade mark. Also, an operation commonly used in road building and other rock and earthmoving operations in which the material excavated and removed from one location is used as fill material at another location.

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Darby (derby, derby float, derby slicker) A stiff straightedge of wood or metal used to level the surface of wet concrete. A portable machine with large paddles like fan blades used to float and finish concrete floors and slabs. A large power-driven machine mounted on wheels that ride on steel pavement forms and is used to finish concrete pavements.

Density Weight per unit volume.

Dispersing Agent An admixture capable of increasing the fluidity of pastes, mortars, or concretes by reduction of interparticle attraction.

Dowel A cylindrical piece of stock inserted into holes in adjacent pieces of material to align and/or attach the two pieces.

Dowel-Bar Reinforcement Short sections of reinforcing steel that extend from one concrete placement into the next. They are used to increase strength in the joint.

Dry Concrete Concrete that has a low water content, making it relatively stiff. The effects are a lower water-cement ratio, less pressure on forms, lower heat of hydration, and a consistency that allows for placement on a sloping surface.

Dry Pack A low-slump grout tamped into the space in a connection between pre-cast concrete members.

Dry Shake (Dry Topping) A concrete surface treatment, such as color, hardening, or antiskid, which is applied to a concrete slab by shaking on a dry, granular material before the concrete has set and then troweling it in.

Drying Shrinkage A decrease in the volume of concrete upon drying.

Durability The ability of concrete to resist weathering action, chemical attack, and abrasion.

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Efflorescence The process by which water leeches soluble salts out of concrete or mortar and deposits them on the surface. Also used as the name for these deposits.

Elastic Shortening The shortening of a member in pre-stressed concrete which occurs on the application of forces induced by prestressing.

Entrained Air Microscopic air bubbles intentionally incorporated in mortar or concrete, to improve workability and durability (usually producing a higher degree of resistance to freezing and thawing).

Entrapped Air Air in concrete which is not purposely en-trained. Entrapped air bubbles are normally much larger and more irregular than entrained air bubbles.

Expansion Joint A surface divider joint that provides space for the surface to expand. It is usually composed of a fibrous material (~1/2" thick) and often installed in and around a concrete slab to permit it to move up and down (seasonally) along the non-moving foundation wall.

Exposed Aggregate Finish A method of finishing concrete which washes the cement/sand mixture off the top layer of the aggregate - usually gravel. It is often used in driveways, patios and other exterior surfaces.

Extension Chute An additional chute used by a concrete contractor to extend the length of the existing chutes from a ready-mix concrete truck. They are frequently used to pour floors.

False Set The rapid development of rigidity in a mixed Portland cement paste, mortar, or concrete without the evolution of much heat. This rigidity can be dispelled and plasticity regained by further mixing without addition of water. Premature stiffening, and rubber set are terms referring to the same phenomenon, but false set is the preferred term.

F Numbers The specification of the degree of flatness that a slab or floor must have. The degree of flatness of a concrete floor is extremely critical for warehouse or manufacturing plant floors where specialized materials handling equipment may be guided by wires under the concrete floor.

Face Forms Concrete forms that are used to create a desired curb profile. They attach to the curb and gutter form set up by hooking to the clips of the division plate. Face forms are designed based on the amount of batter specified.

Faced Concrete To finish the front and all vertical sides of a concrete porch, step(s), or patio. Normally the "face" is broom finished.

Fat Mix / Rich Mix A mortar or concrete mix with a relatively high cement content. Fat mix is more easily spread and worked than a mix with the minimum amount of cement required for strength.

Fiber Reinforced Concrete A variant of concrete that is produced by adding fibers made of stainless steel, glass, carbon or polypropylene to the mixture.

Fibrous Admixture Special fibrous substances of glass, steel, or polypropylene that are mixed into concrete to act as a reinforcement against plastic shrinkage cracking.

Fine Aggregate Aggregate passing the 3/8-in. sieve and almost entirely passing the No.4(4.76 mm) sieve and predominantly retained on the No. 200 (74 micron) sieve(ASTM125).

Fineness Modulus An index of fineness or coarseness of an aggregate sample. An empirical factor determined by adding total percentages of an aggregate sample retained on each of a specified series of sieves, and dividing the sum by 100. Note: US Standard sieve sizes are used: No. 100, No.50, No. 30, No. 16, No. 8, and No. 4, and 3/8 in., 3/4 in., I in., 2 in., 3 in., and 6 in.

Finishing Leveling, smoothing, compacting, and otherwise treating surfaces of fresh or recently placed concrete to produce the desired appearance and service.

Fixed Nose Form A metal concrete pouring form with a fixed nose piece to allow it to interlock with the rear section of another form creating a solid interconnection. Fixed nose forms must be removed in order or reverse order after a pour due to their interlocking nature.

Flash Set The rapid development of rigidity in a mixed Portland cement paste, mortar or concrete usually with the evolution of considerable heat, which rigidity cannot be dispelled nor can the plasticity be regained by further mixing without addition of water Also referred to as quick set or grab set.

Flatwork Common word for concrete floors, driveways, basements, and sidewalks.

FlatworkForms Metal or wood forms used in concrete flatwork placement. These forms are typically used for edge forming, sidewalks, driveways, footings, industrial slabs, foundations, patios, general flatwork, and in curb and gutter work.

Flexible Forms Metal forms used to form radius shapes such as islands, serpentine sidewalks, curved curbs, parking lot turnouts, and similar applications. They are made from spring steel and are typically 10 feet long with stake pockets riveted onto the form every 18". They range in height form 4" to 12". The same as radius forms.

Flexural Strength A property of a solid that indicates its ability to withstand bending.

Float A tool (not a darby), usually of wood, aluminum, magnesium, rubber, or sponge, used in concrete or tile finishing operations to impart a relatively even but still open texture to an unformed fresh concrete surface.

Floating The operation of finishing a fresh concrete or mortar surface by use of a hand float or bull float smoothing and bringing water to the surface, preceding troweling when that is the final finish.

FloatingWall A non-bearing wall built on a concrete floor. It is constructed so that the bottom two horizontal plates can compress or pull apart if the concrete floor moves up or down. A floating wall is normally built on basements and garage slabs.

Fly Ash The finely divided residue that results from the combustion of ground or powdered coal, transported from the firebox through the boiler by flue gases. Fly ash contains aluminosilicate and small amounts of lime. It is a concrete admixture.

Footing The widened portion of the foundation or a structure that spreads and transmits the load from the building or foundation directly to, and across a broader area of, the soil. A continuous 8" or 10" thick concrete pad installed before construction that supports the foundation wall or monopost.

Form A temporary erected structure or mold for the support and containment of concrete during placement and while it is setting and gaining sufficient strength to be self-supporting.

Form Release Agent Material used to prevent bonding of concrete to a surface, such as to forms.

Forming The use of metal or wood forms to create the proper placement of concrete. The forming process channels the concrete into the desired shape and thickness.

Formwork Temporary structures or forms made of wood, metal, or plastic used in the placing of concrete to ensure the slurry is shaped to its desired final form. Formwork must be strong enough to support the considerable weight and pressure of wet concrete without deflection.

Foundation The entire masonry substructure below the first floor or frame of a building, including the footing upon which the building rests.

Foundation Form Sets Custom made sets of metal concrete forms used for houses, garage, car port, strip mall, warehouse floors, and other structures which require slab on grade foundations.

Foundation Ties Metal wires that hold the foundation wall panels and rebar in place during the concrete pour.

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Gap-graded Aggregate Aggregate containing particles of both large and small sizes, in which particles of certain intermediate sizes are wholly or substantially absent.

Glass Fiber Reinforced Concrete (GFRC) Concrete panels, usually architectural designs, reinforced with a high zirconia (16% minimum), alkali-resistant glass fiber. Optimum glass fiber content of 5% by weight. Lower fiber content results in lower early ultimate strengths; higher fiber content can produce composite compaction and consolidation difficulties. It is usually a thin cementitious material laminated to plywood or other lightweight backing.

Gillmore Needle A device used in determining time of setting of hydraulic cement, described in ASTM 0 266.

Gradation The sizing of granular materials; for concrete materials, usually expressed in terms of cumulative percentages larger or smaller than each of a series of sieve openings or the percentages between certain ranges of sieve openings.

Grade The surface or level of the ground. The existing or proposed ground level or elevation on a building site or around a building. The slope or rate of incline or decline of a road, expressed as a percent. A designation of a subfloor, either above grade, on grade, or below grade. Any surface prepared to accept paving, conduit, or rails.

Grade Line A strong string used to establish the top of a concrete placement.

Grout A fluid mixture of cement, sand, and water or cement and water. The hardened equivalent of such mixtures. A high-slump mixture of Portland cement, aggregates, and water which can be poured or pumped into cavities in concrete or masonry for the purpose of embedding reinforcing bars, and/or increasing the amount of load-bearing material in a wall.

Gunite A term sometimes used to designate dry-mix shotcrete.

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Hand Float A wooden tool used to lay on and to smooth or texture a finish coat of plaster or concrete.

Hangers A straight metal bar with pockets on an adjustable slide that allow straight forms to be placed in areas where securing forms into position is difficult due to soil conditions, existing pavement, or obstacles. Hangers are often used in applications such as sidewalks, foundations, and curb and gutter work.

Hardener The curing agent of a two-part synthetic resin, adhesive, or similar coating.

Heat of Hydration The quantity of heat expressed in calories per gram, evolved upon complete hydration of Portland cement at a given temperature.

HoldingPeriod In the manufacture of concrete products, the period between completion of casting and the introduction of additional heat or steam curing period.

Honeycomb An area in a foundation wall where the aggregate (gravel) is visible. Honeycombs can be usually be remedied by applying a thin layer of grout or other cement product over the affected area. A method by which concrete is poured and not puddled or vibrated, allowing the edges to have voids or holes after the forms are removed.

Hot Load Construction slang used to describe ready-mix concrete that has begun its hydration process while still in the delivery drum of the agitator truck. Hydration causes heat build up in the concrete mix.

HRM (High Reactivity Metakaolin) Refined form of an ASTM C618, Class N (natural) pozzolan. A high performance, mineral admixture, similar in performance to silica fume. The pure white powdered form will not affect the natural color or darken concrete as silica fume does. Suitable for high-performance color matching in architectural concrete.

Hydration The chemical reaction that occurs when cement is mixed with water. A concrete slab needs to completely hydrate prior to the application of paints, coatings, and flooring materials.

Hydraulic Cement A variety of cement engineered to harden under water (ASTM 219).

Hydrogenesis Another term for condensation. The term is especially applied to base and soil substrates under highway pavements where the barometric pump causes the inhalation of humid air, which then condenses in those structures, causing an ever increasing moisture content and sometimes instability.

Impermeable The ability of a material or product to reduce or eliminate gaseous transmissions through it's mass; measured as the rate of Water Vapor Transmission (WVT). Note: Not all materials that are waterproof are vaporproof; all materials that are vaporproof are inherently waterproof.

Initial Set A degree of stiffening of the cement and water mixture. This is a degree less than final set and is generally stated as an empirical value, indicating the time in hours and minutes required for a cement paste to stiffen sufficiently to resist to an established degree the penetration of a weighted test needle. (Refer to ASTM C191 or C286 for weight and penetration data.)

Initial stress In prestressed concrete, the stresses occurring in the prestressed members before any losses occur.

Jacking Equipment In prestress concrete, the device used to stress the tendons.

Jacking Force The temporary force exerted by the jacking device which introduces tension into the tendons.

Jacking Stress In prestress concrete, the maximum stress occurring in a tendon during stressing.

Jitterbug A grate tamper used to bring sand and cement grout to the surface of wet concrete during placement of slabs. May be motorized or hand operated.

Joint Position where two or more building materials, components or assemblies are put together, fixed or united, with or without the use of extra jointing products. The location between the touching surfaces of two members or components joined and held together by nails, glue, cement, mortar, or other means.

Keene 's Cement A finely ground high density plaster composed of anhydrous, (calcined or "dead burned") gypsum, the set of which is accelerated by the addition of other materials.

Kelly Ball A device for determining the consistency of fresh concrete, sometimes used as an alternative to the slump test.

Key A slot formed into a concrete surface for the purpose of interlocking with a subsequent pour of concrete.

Keyway A recess or groove in one lift or placement of concrete that is filled with concrete of the next lift, giving shear strength to the joint.

Laitance A residue of weak and non-durable material consisting of cement, aggregate, fines, or impurities brought to the surface of overwet concrete by the bleeding water

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Lateral Force A force acting in a generally horizontal direction, such as wind, earthquake, or soil pressure against a foundation wall.

Lift Layer of concrete.

Lift-Slab Construction A building method for multi-story site-cast concrete buildings that casts all the slabs in a stack on the ground and then lifts them up the columns and welds them into place.

Long Float A concrete finishing float designed to be handled by two men.

Low-Lift Grouting The common and simple method of unifying concrete masonry, in which the wall sections are built to a height of not more than 4" before the cells of the masonry units are filled with grout.

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Magnetite An aggregate used in heavy weight concrete, consisting primarily of ferrous metaferrite (Fe304). A black magnetic iron ore with a specific gravity of approximately 5.2 and a Mohs hardness of about 6.

Marl A calcareous clay, containing approximately 30 to 65 percent calcium carbonate (05003), found normally in extinct fresh wafer basins, swamps, or bottoms of shallow lakes.

Masonry Construction composed of shaped or molded units, usually small enough to be handled by one man and composed of stone, ceramic brick, or tile, concrete, glass, adobe, or the like. The term masonry is sometimes used to designate cast-in-place concrete.

Masonry Cement Hydraulic cement manufactured for use in mortars for masonry construction. Normally a blend of two or more of the following materials: Portland cement, natural cement, Portland-pozzolan cement, hydraulic lime, slag cement, hydrated lime, pulverized limestone, talc, chalk, pozzolan, clay or gypsum; also may include air entraining additions.

Mass Concrete Any large volume of concrete cast in place intended to resist applied loads by virtue of mass. Generally a monolithic structure incorporating a low cement factor with a high proportion of large coarse aggregate.

Mass Curing Adiabatic curing, using sealed containers.

Maturing The curing and hardening of construction materials such as concrete, plaster, and mortar.

Maul A heavy mallet with an oversized wooden head used for driving wood takes, pegs, or wedges into the ground or in other applications where material might sustain damage if struck with a conventional sledgehammer. It is also referred to as a "beetle".

Maximum Size Aggregate Aggregate whose largest particle size is present in sufficient quantity to affect the physical properties of concrete; generally designated by the sieve size on which the maximum amount permitted to be retained is 5 or 10 percent by weight.

Membrane Curing A process of controlling the curing of concrete by sealing in the moisture that would be lost to evaporation. The process is accomplished either by spraying a sealer on the surface or by covering the surface with a sheet film.

Mix A general term referring to the combined ingredients of concrete or mortar. Examples might be a six-bag mix, a lean mix, or a 3,000-psi mix.

Mixing Speed Rate of mixer drum rotation or that of the paddles in a pan, open-top, or trough type mixer, when mixing a batch; expressed in revolutions per minute (rpm) or in peripheral feet per minute of a point on the circumference at maximum diameter.

Mixing Time The period during which materials used in a batch of concrete are combined by the mixer. For stationary mixers, mixing time is calculated in minutes from the completion of charging the mixer until the beginning of discharge. For truck mixers, time is calculated in total minutes at a specified mixing speed.

Modulus of Elasticity An engineering term used to describe a material's ability to bend without losing its ability to return to its original physical properties.

Monolithic A plain or reinforced mass of concrete cast as a single, one piece, integral structure.

Monolithic Surface Treatment A concrete finish obtained by shaking a dry mixture of cement and sand on a concrete slab after strike-off, then troweling it into the surface.

Mortar A mixture of cement, sand and water. When used in masonry construction, the mixture may contain masonry cement, or standard portland cement with lime or other ad-mixtures which may produce greater degrees of plasticity and/or durability.

Mortar Board A mason's hand tool used to hold small amounts of material that is typically being applied to a vertical surface with a hand trowel. The mortar board is a square flat piece of wood or metal with a handle placed in its center on the bottom side. It is often used in patching and finish work.

Mud Slab A base slab of low-strength concrete from 2" to 6" thick placed over a wet sub-base before placing a concrete footing or grade slab.

Mule A hand-held or machine mounted device used to shape concrete by dragging or pressing it over the form boards. This device is commonly used in curb and gutter work.

Mushroom The unacceptable occurrence when the top of a caisson concrete pier spreads out and hardens to become wider than the foundation wall thickness.

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Neat Cement Unhydrated hydraulic cement.

Neat Cement-Paste A mixture of water and hydraulic cement, both before and after setting and hardening.

No-Fines Concrete A concrete mixture in which only the coarse gradation (3/8' to 3/4' normally) of aggregate issued.

Non-Agitating Unit A truck-mounted unit for transporting ready-mixed concrete short distances, not equipped to provide agitation (slow mixing) during delivery.

Non-Air-Entrained Concrete Concrete in which neither an air-entraining admixture nor air-entraining cement has been used.

Ottawa Sand A sand used as a standard in testing hydraulic cements by means of mortar test specimens. Sand is produced by processing silica rock particles obtained by hydraulic mining of the orthoquartzite situated in open-pit deposits near Ottawa, Illinois.

Overvibration Excessive vibration of freshly mixed concrete during placement-causing segregation.

Parging Portland cement plaster applied over masonry to make it less permeable to water.

Particle-Size Distribution Particle distribution of granular materials among various sizes. Usually expressed in terms of cumulative percentages smaller or larger than each of a series of sieve openings or percentages between certain ranges of sieve openings.

Paving Forms Heavy duty metal forms used in the placement of concrete for concrete roadways, commercial driveways, intersection entrance and exit ramps, and airport work.

Paving Machine A self-propelled piece of construction equipment that forms and finishes concrete simultaneously.

Pea Gravel Portion of concrete aggregate passing the 3/8' sieve and retained on a No.4 sieve.

Peeling A process in which thin flakes of matrix or mortar are broken away from concrete surface. Caused by adherence of surface mortar to forms when forms are removed, or to trowel or float in portland cement plaster.

Pining Development of relatively small cavities in a concrete surface, due to phenomena such as cavitation or corrosion.

Pitch The amount of angle or slope used in concrete flatwork to disperse water.

Pitch-In A curb and gutter profile designed to accept water into the flow-line of the gutter. It is also referred to as wet-curb.

Pitch-Out A curb and gutter profile designed to direct water away form the curb. It is also known as a dry-curb or spill-out curb.

Placement The process of placing and consolidating concrete. A quantity of concrete placed and finished during a continuous operation. Also, inappropriately referred to as pouring.

Placing The deposition, distribution, and consolidation of freshly mixed concrete in the place where it is to harden. Also, inappropriately referred to as pouring.

Plain Concrete Concrete without reinforcement, or reinforced only for shrinkage or temperature changes.

Plane of Weakness The plane along which a structure under stress will tend to fracture; may exist because of the nature of the structure and its loading, by accident or by design.

Plant Mix Any mixture produced at a mixing plant.

Plastic Consistency Condition in which concrete, mortar, or cement paste will sustain deformation continuously in any direction without rupture.

Plasticity Property of freshly mixed concrete, cement paste or mortar which determines its ease of molding or resistance to deformation.

Plasticizer A material that increases the workability or consistency of a concrete mixture, mortar or cement paste.

Polyethylene A thermoplastic widely used in sheet form for vapor retarders, moisture barriers, and temporary construction coverings.

Porosity The ratio of the volume of voids in the material to the total volume of the material, including the voids, usually expressed as a percentage.

Portland Cement (ASTM C 150) A special synthetic blend of limestone and clay used to make concrete which is generally believed to be stronger, more durable, and more consistent than concrete made from natural cement. It is a hydraulic cement consisting of finely pulverized compounds of silica, lime, and alumina.

Portland-Pozzolan Cement (ASTM C 595) The product obtained by intimately intergrinding a mixture of Portland-cement clinker and pozzolan, or an intimate and uniform blend of Portland cement and fine pozzolan.

Post-tensioning A method of prestressing concrete in which tendons are tensioned after the concrete has hardened.

Pour To cast concrete. A pour is an increment of concrete casting carried out without interruption.

Pozzolan (ASTM C 618) A mineral admixture. A siliceous, or siliceous and aluminous material, which in itself possesses little or no cementitious value but will, in a finely divided form, such as a powder or liquid and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form permanent, insoluble compounds possessing cementitious properties.

Precast A concrete unit, structure or member that is cast and cured in an area other than its final position or place.

Preplaced Concrete Concrete manufactured by placing clean, graded coarse aggregate in a form and later injecting a Portland cement-sand grout under pressure, to fill the voids.

Proportioning Selection of proportions of material for concrete to make the most economical use of available materials to manufacture concrete of the required strength, placeability, and durability,

Prestressed Concrete Concrete in which stresses have been introduced which are opposite in sense to those that the structural member will be expected to carry during its use, which may eliminate the need for steel reinforcement. In reinforced concrete, the pre-stress is commonly introduced by tensioning the tendons.

Pre-Stressed Concrete Wire Steel wire with a very high tensile strength, used in pre-stressed concrete. The wire is initially stressed close to its tensile strength. Then some of this load is transferred to the concrete, by chemical bond or mechanical anchors, to compress the concrete.

Pretensioning A method of prestressing reinforced concrete in which the steel is stressed before the concrete has hardened and restrained from gaining its unstressed position by bond to the concrete.

Pump Mix Special concrete used in a concrete pump. Generally, the mix has smaller rock aggregate than regular concrete mix.

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Radius Forms Metal forms used to form radius shapes such as islands, serpentine sidewalks, curved curbs, parking lot turnouts, and similar applications. Also known as flexible forms.

Reactive Aggregate Aggregate containing substances capable of reacting chemically with the products of solution or hydration of the Portland cement in concrete or mortar, under ordinary conditions of exposure, resulting in harmful expansion, cracking, or staining.

Ready-Mixed Concrete Concrete that is batched or mixed at a central plant before it is delivered to a construction site and delivered ready for placement. It is also known as transit-mixed concrete since it is often transported in an agitator truck.

Rebar The ribbed steel bars installed in foundation concrete walls, footers, and poured in place concrete structures designed to strengthen concrete. Rebar comes in various thickness' and strength grade. The term rebar is short for reinforcing bar.

Refractory Concrete Concrete suitable for use at high temperatures, as in wood burning ovens for pizza. Calcium-aluminate cement and refractory aggregates are normally used for the manufacture of this product.

Reinforced Concrete Concrete reinforced by the addition of steel bars making it more able to tolerate tension and stress.

Release Agent Material used to prevent bonding of concrete to a surface, such as to forms.

Retardation Delaying the hardening or strength gain of fresh concrete, mortar or grout.

Retarder An admixture which extends the setting time of cement paste, and therefore of mixtures such as concrete, mortar, or grout.

Retempering The addition of water and remixing of concrete which has started to stiffen: usually not acceptable as it may affect the ultimate strength.

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.

Road Forms Heavy duty 3/16" or 1/4" metal paving forms capable of supporting large screed machines. The screed machines ride on the top rails of the paving forms to level the concrete.

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

Rod (tamping) (ASTM C24l) 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'.

Rodding Compaction of concrete or the like by means of a tamping rod.

Rotary Float (Power Float) Motor-driven revolving blades that smooth, flatten, and compact the surface of concrete slabs or floor toppings.

Sacking/Sack Rub/Sack Finish 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.

Sand (ASTM C125) That portion of an aggregate passing the No. 4 (4.76 mm) sieve and predominantly retained on the No. 200 (74 micron) sieve.

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

Scaling T he local flaking or peeling of a hardened concrete surface , usually less than 1/8 th inch, caused primarily by hydraulic pressures from freeze-thaw cycles affecting the concrete at the surface.

Screed To level off concrete to the correct elevation during a concrete pour. To strike off concrete lying above the desired plane or shape. A screed is also a tool for striking off the concrete surface, sometimes referred to as a strike off.

Screed Guide/Screed Rail Firmly established grade strips or side forms for unformed concrete that will guide the strike off in producing the desired plane or shape.

Screen(or Sieve) 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.

Segregation The tendency for the coarse particles to separate from the finer particles caused by excessive handling or vibration. 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.

Separation The tendency of coarse aggregate to separate from the concrete and accumulate at one side as concrete passes from the unconfined ends of chutes, conveyor belts, or similar arrangements.

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.)

Set Retarders Agents used to delay or slow down the setting of concrete.

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.

Settlement Sinking of solid particles in grout, mortar, or fresh concrete, after placement and before initial set.

Shake-On Hardener A dry powder that is dusted onto the surface of a concrete slab before troweling to react with the concrete and produce a hard-wearing surface for industrial uses.

Shotcrete Mortar or concrete conveyed through a hose and projected pneumatically at high velocity onto a surface.

Shrinkage A reduction in volume of concrete prior to the final set of cement, caused by settling of the solids and by the decrease in volume due to the chemical combination of water with cement.

Site-Cast Concrete Concrete that is poured and cured in its final position at a construction project.

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

Slab (concrete) Concrete pavement that would be found in driveways, garages, and basement floors.

Slab on Grade A type of foundation with a concrete floor that is placed directly on the soil. The edge of the slab is usually thicker and acts as the footing for the walls.

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.

Slip Form A form which is raised or pulled as concrete is placed. Slip forms may move vertically to form walls, 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.

Slip Forming The process of simultaneously extruding and finishing concrete pavement, curb and gutter combinations, median barriers, and like applications using a paving machine.

Slope The incline angle of a sidewalk or road surface, given as a ratio of the rise (in inches) to the run (in feet).

Slump The "wetness" of concrete. A measure of the consistency of plastic concrete relative to the amount it falls when a slump cone filled with concrete is lifted vertically. A 3 inch slump is dryer and stiffer than a 5 inch slump.

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 Loss The amount by which the slump of freshly mixed concrete changes during a period of time after an initial slump test was made on a sample.

Slump Test A test to determine the plasticity of concrete. A sample of wet concrete is placed in a cone-shaped container 12" high. The cone is removed by slowly pulling it upward. 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 specimen of concrete is the slump (see ASTM C143). If the concrete flattens out into a pile 4" high, it is said to have an 8" slump. This test is done on the job site. If more water is added to the concrete mix, the strength of the concrete decreases and the slump increases.

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.

Spalling The chipping or flaking of concrete, bricks, or other masonry This condition due to the over use of salt, numerous freeze/thaw cycles, improper drainage or venting or an inferior concrete mix.

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.

Specifications or Specs A narrative list of materials, methods, model numbers, colors, allowances, and other details which supplement the information contained in the blue prints. Written elaboration in specific detail about construction materials and methods. Specs are written to supplement working drawings.

Spring Steel A high alloy metal that will spring back to its original shape after being formed or bent into another shape. It is often used to manufacture flexible forms.

Steam Curing Curing of concrete or mortar in water vapor at atmospheric or higher pressures and at temperatures between about 100° and 420° F (40° and 215° C). Usually used in pre-cast concrete operations.

Steel Trowel A steel hand tool or machine used to create a dense, smooth finish on a concrete surface.

Straight Forms Formed metal channels, typically 10 feet long, with a height that varies from 4" to 24" and used for straight concrete forming and pours. The width of the base can vary between 2" and 4" dependent on form height and application. The top rail of the form is typically 2" wide. Applications for straight forms include, front and back form for curb and gutter setups, sidewalks, patios, retaining walls, foundation footers, and similar applications.

Straightedge A rigid and straight, piece of wood or metal used to strike off or screed a concrete surface to the proper grade, or to check the flatness of a finished grade.

Strike Off To remove excess concrete evenly from a form or bring the surface to grade. Usually performed with a straight-edged piece of wood or metal by means of a forward sawing movement or by a power-operated tool.

Stripping Removing the formwork from concrete.

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.

Sub-Base Clay or soil material used underneath a stone base.

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.

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

Super Flat Floor A concrete slab finished to a high degree of flatness according to recognized systems of measurement.

Superplasticizer A concrete admixture that makes wet concrete extremely fluid without additional water. These agents perform the same function as a plasticizer, but are composed of different materials.

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

Swirl Finish A nonskid texture imparted to a concrete surface during final troweling by keeping the trowel flat and using a rotary motion.

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Tamper An implement used to consolidate concrete or mortar in molds or forms. A hand-operated device for compacting floor topping or other unformed concrete by impact from the dropped device in preparation for strike off and finishing. Contact surface often consists of a screen or a grid of bars to force coarse aggregates below the surface that prevents interference with floating or troweling. It is also known as a jitterbug.

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.

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

Tendon A steel element such as a wire, cable, bar, rod, or strand used to impart pre-stress to concrete when the element is tensioned.

Tensile Strength Maximum unit stress which a material is capable of resisting under axial tensile loading, based on the cross sectional area of the specimen before loading.

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

Tilt-Up Reversible Forms Specially engineered forms with two-sided formed metal channels used to pour horizontal concrete slabs that will later be tilted up to vertical and fastened in place and used as walls. Each side of the tilt-up form will have a different height so that two different wall thickness depths can be poured using the same set of forms.

Tilt-Up Wall Cast concrete units which are preformed which, when cured, are tilted to their vertical position and secured by mechanical fasteners to prior erected structural steel. Tilt-up wall units may be pre-cast.

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.

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. The bottom is kept beneath the surface of the concrete and raised as the form is filled.

Trowel A thin, flat steel tool, either pointed or rectangular, provided with a handle and held in the hand, used to manipulate concrete, mastic, or mortar to create a dense, smooth finish on a concrete surface. It is also a machine whose rotating blades are used to finish concrete slabs.

Trowel Finish The smooth finish surface produced by troweling.

Troweling Smoothing and compacting the unformed surface of fresh concrete by strokes of a trowel.

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

Truckload or Trailerload A quantity of commodities weighing as much as 44,000 pounds, which is the standard weight limit on U.S. highways.

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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.

Unbonded Construction Posttensioned concrete construction in which the tendons are not grouted to the surrounding concrete.

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

Unreinforced Concrete Concrete made without steel reinforcing bars.

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.

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.

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.

Vermiculite An aggregate similar to perlite that is used in lightweight roof decks and deck fills. It is formed from mica, a hydrous silicate with the ability of expanding on heating to form lightweight material with insulation quality. Used as bulk insulation and also as aggregate in insulating and acoustical plaster and in insulating concrete.

Vibrating Screed A machine designed to act as a vibrator while leveling freshly placed concrete.

Vibration Energetic agitation of freshly mixed concrete during placement by mechanical devices, either pneumatic or electric, that create vibratory impulses of moderately high frequency that assist in evenly distributing and consolidating the concrete in the formwork. External vibration employs a device attached to the forms and is particularly applicable to the manufacture of precast items and for the vibration of tunnel lining forms. Internal vibration employs an element which can be inserted into the concrete; and is more generally used for cast-in-place construction.

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

Visqueen A 4 mil or 6 mil plastic sheeting often used for construction coverings.

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.

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-Reducing Agents A material that either increases workability of freshly mixed mortar or concrete without increasing water content, or maintains workability with a reduced amount of water; the effect being due to factors other than air entrainment.

Water Stop A synthetic rubber strip used to seal joints in concrete foundations walls.

Weep Screed A tool used to drain moisture from concrete.

Wet Screeds Concrete strips placed beforehand at the proper elevation to act as height guides when pouring a concrete slab.

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 uniformity.

Yard (of concrete) One cubic yard of concrete is 3' x 3' x 3' in volume, or 27 cubic feet. One cubic yard of concrete will pour 80 square feet of 3.5' sidewalk or basement/garage floor.

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.

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