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Concrete Waterproofing Glossary

Abrams’ Law

a rule stating that, with given concrete materials and conditions of test, the ratio of the amount of water to the amount of the cement in the mixture determines the strength of the concrete, provided the mixture is of a workable consistency.

Abrasion Damage

wearing away of a surface by rubbing and friction. (See also cavitation damage and erosion.)

Abrasion Resistance

ability of a surface to resist being worn away by rubbing and friction.

Absolute Volume

(1) in the case of solids, the displacement volume of particles themselves, including their permeable and impermeable voids, but excluding space between particles;
(2) in the case of fluids, their volume.

Absorbed Moisture

moisture that has entered the permeable pores of a solid and has physical properties not substantially different from ordinary water at the same temperature and pressure. (See also absorption.)

Abutment

(1) in bridges, the end foundation that is typically constructed with concrete that supports the superstructure of the bridge;
(2) in dams, the side of the gorge or bank of the stream against which a dam abuts.

Accelerating Admixture

an admixture that causes an increase in the rate of hydration of the hydraulic cement and thus shortens the time of setting, increases the rate of strength development, or both.

Acceleration

increase in rate of natural progress of setting or hardening of concrete. (See also accelerating admixture.)

Active Crack

a crack whose width changes with time.

Addition

a material that is interground or blended in limited amounts into a hydraulic cement during manufacture either as a processing addition to aid in manufacturing and handling the cement or as a functional addition to modify the use properties of the finishe

Additive

a substance added to another in relatively small amounts to impart or improve desirable properties or suppress undesirable properties.

Adhesion

the state in which two surfaces are held together by interfacial effects that may consist of molecular forces, interlocking action, or both.

Adhesives

the group of materials used to join or bond similar or dissimilar materials, for example, in concrete work, the epoxy resins.

Adiabatic

a condition in which heat neither enters or leaves a system.

Admixture

a material other than water, aggregates, cementitious materials, and fiber reinforcement, used as an ingredient of a cementitious mixture to modify its freshly mixed, setting, or hardened properties and that is added to the batch before or during its mixi

Adsorbed Water

water held on surfaces of a material by electrochemical forces and having physical properties substantially different from those of absorbed water 1 or chemically combined water at the same temperature and pressure. (See also adsorption.)

Adsorption

(1) development of a higher concentration of a substance at the surface of either a liquid or solid, such as cement, cement paste, or aggregates, than exists in the bulk of the medium;
(2) the process by which a substance is adsorbed. (See also adsorbed

Agent

a general term for a material that may be used either as an addition to cement or an admixture in concrete, for example, an air-entraining agent.

Agglomeration

a gathering into a ball or mass.

Aggregate

granular material, such as sand, gravel, crushed stone, crushed hydraulic- cement concrete, or iron blast-furnace slag, used with a cementing medium to produce either concrete or mortar. (See also heavyweight aggregate and lightweight aggregate.)

Aggregate Blending

the process of intermixing two or more aggregates to produce a combination with improved grading or other properties.

Aggregate Transparency

discoloration of a concrete surface consisting of darkened areas over coarse aggregate particles immediately below the concrete surface.

Aggregate-cement Ratio

the ratio of total aggregate to cement, either by mass or volume.

Agitating Speed

the rate of rotation of the drum of a truck mixer or agitator when used for agitating mixed concrete.

Agitating Truck

a vehicle in which freshly mixed concrete can be conveyed from the site of mixing to the site of placement; while being agitated, the truck body can either be stationary and contain an agitator or it can be a drum rotated continuously so as to agitate the

Agitation

(1) the process of providing motion in mixed concrete just sufficient to prevent segregation or loss of workability;
(2) the mixing and homogenization of slurries or finely ground powders by either mechanical means or injection of air. (See also agitator

Agitator

a device for maintaining workability and preventing segregation of mixed concrete by agitation. (See also agitation.)

Air Content

the volume of air voids in cement paste, mortar, or concrete, exclusiveof pore space in aggregate particles, usually expressed as a percentage of total volume of the paste, mortar, or concrete.

Air Entraining

the capability of a material or process to develop a system of microscopic bubbles of air in cement paste, mortar, or concrete during mixing. (See also air entrainment.)

Air Entrainment

the incorporation of air in the form of microscopic bubbles (typically smaller than 1 mm [0.04 in.]) during the mixing of either concrete or mortar. (See also air entraining and entrained air.)

Air Meter

a device for measuring the air content of concrete and mortar.

Air Ring

perforated manifold in nozzle of wet-mix shotcrete equipment throughwhich high-pressure air is introduced into the material flow.

Air Void

a space in cement paste, mortar, or concrete filled with air. (See alsoentrained air and entrapped air.)

Air-entraining Admixture

an admixture that causes the development of a system of microscopic air bubbles in concrete, mortar, or cement paste during mixing, usually to increase its workability and resistance to freezing and thawing. (See also entrained air.)

Air-permeability Test

a procedure for measuring the fineness of powdered materials such asportland cement. (See also Blaine test.)

Air-water Jet

a high-velocity jet of air and water mixed at the nozzle, used in clean-up of surfaces of rock or concrete, such as horizontal construction joints.

Alkali

salts of alkali metals, principally sodium and potassium; specifically sodium and potassium occurring in constituents of concrete and mortar, usually expressed in chemical analyses as the oxides Na 2 O and K 2 O. (See also low-alkali cement.)

Alkali Reactivity (of Aggregate)

susceptibility of aggregate to alkali-aggregate reaction.

Alkali-aggregate Reaction

chemical reaction in either mortar or concrete between alkalies (sodium and potassium) from portland cement or other sources and certain constituents of some aggregates.

Alkali-carbonate Rock Reaction

the reaction between the alkalies (sodium and potassium) in portland cement and certain carbonate rocks, particularly calcitic dolomite and dolomitic limestones, present in some aggregates.

Alkali-silica Reaction

the reaction between the alkalies (sodium and potassium) in portland cement and certain siliceous rocks or minerals, such as opaline chert, strained quartz, and acidic volcanic glass, present in some aggregates.

Alkyl Aryl Sulfonate

synthetic detergent used to entrain air in hydraulic-cement mixtures.

Allowable Bearing Capacity

the maximum pressure to which a soil or other material should be subjected to guard against shear failure or excessive settlement.

Allowable Load

see service dead load and service live load.

Allowable Stress

maximum permissible stress used in design of members of a structure and based on a factor of safety against rupture or yielding of any type.

Aluminate Concrete

concrete made with calcium-aluminate cement.

Amount of Mixing

the extent of mixer action employed in combining the ingredients for either concrete or mortar; in the case of stationary mixers, the mixing time; in the case of truck mixers, the number of revolutions of the drumat mixing speed after the intermingling of

Amplitude

the maximum displacement from the mean position in connection with vibration.

Anchor

(1) in prestressed concrete, to lock the stressed tendon in position so that it will retain its stressed condition;
(2) in precast-concrete construction, to attach the precast units to the building frame;
(3) in slabs-on-grade orwalls, to fasten to rock

Anchor Bolt

a metal bolt or stud, headed or threaded, cast in place, grouted in place,or drilled and fastened into existing concrete either by expansion or by chemical adhesives.

Anchorage

(1) in post-tensioning, a device used to anchor the tendon to the concrete member;
(2) in pretensioning, a device used to maintain the elongationof a tendon during the time interval between stressing and release;
(3) in precast-concrete construction, th

Anchorage Zone

(1) in post-tensioning, the region adjacent to the anchorage subjected to secondary stresses resulting from the distribution of the prestressing force;
(2) in pretensioning, the region in which the transfer bond stresses are developed.

Anhydrite

(1) a mineral, anhydrous calcium sulfate (CaSO 4 );
(2) gypsum from which the water of crystallization has been removed, usually by heating above 325°F (160°C).

Anhydrous Calcium Chloride (CaCl 2 )

a solid, usually 94 percent calcium chloride, typically in pellet form.

Anti-washout Admixture

a concrete admixture that reduces the loss of fine material from concretewhen placed in water.

Apparent Specific Gravity

the ratio of the mass of a volume of the impermeable portion of a material at a stated temperature to the mass of an equal volume of distilled water at a stated temperature.

Architect-engineer

architect, engineer, architectural firm, engineering firm, or architectural and engineering firm issuing contract documents, administering the work under contract documents, or both (also called engineer-architect).

Architectural Concrete

concrete that will be permanently exposed to view and therefore requires special care in selection of the concrete materials, forming, placing, and finishing to obtain the desired architectural appearance.

Area of Steel

the cross-sectional area of the steel reinforcement.

Arenaceous

composed primarily of sand; sandy.

Argillaceous

composed primarily of clay or shale; clayey.

Arris

the sharp external corner edge that is formed at the junction of two planes or surfaces.

Arrissing Tool

a tool similar to a float, but having a form suitable for rounding an edge offreshly placed concrete.

Artificial Pozzolan

materials such as fly ash and silica fume. (See also fly ash and silica fume) .

Ashlar Masonry

masonry composed of bonded blocks of concrete, either rectangular or square, always of two or more sizes.

Asphalt

a dark brown to black cementitious material in which the predominatingconstituents are bitumens that occur in nature or are obtained in petroleum processing.

Asphalt Cement

asphalt that is refined to meet specifications for use in the manufacture ofbituminous pavements.

Asphaltic Concrete

a mixture of asphalt cement and aggregate.

Atmospheric-pressure Steam Curing

steam curing of concrete products or cement at atmospheric pressure, usually at maximum ambient temperature between 100 to 200°F (40 to95°C).

Autoclave

a high-pressure steam vessel.

Autoclave Curing

curing of concrete products in an autoclave at maximum ambient temperature generally between 340 and 420°F (170 and 215°C).

Autoclave Cycle

(1) the time interval between the start of the temperature-rise period and the end of the blowdown period;
(2) a schedule of the time and temperature-pressure conditions of periods that make up the cycle.

Autogenous Healing

a natural process of filling and sealing dormant cracks in concrete or inmortar when kept damp.

Autogenous Length Change

length change caused by autogenous volume change. (See alsoautogenous volume change.)

Autogenous Volume Change

change in volume due to the chemical process of hydration of cement, exclusive of effects of applied load and change in either thermal condition or moisture content.

Auxiliary Reinforcement

reinforcement in addition to that required by analysis for strength.

Average Bond Stress

the force in a bar divided by the product of the perimeter and the development length of the bar.

Axle Load

the portion of the gross weight of a vehicle transmitted to a structure or a roadway through wheels supporting a given axle.

Axle-steel Reinforcement

either plain or deformed reinforcing bars rolled from axle steel.