Concrete Terminology » E
early ages (of concrete)—the period following the time of final setting during which properties are changing rapidly and heat evolution is important; for concrete made with Type I cement stored moist at 73 F (23 C), it is the first 72 h.
early stiffening—see stiffening, early.
earth pigments—the class of pigments that are produced by physical processing of materials mined directly from the earth; also frequently termed natural or mineral pigments or colors.
eccentric tendon—see tendon, eccentric.
edge, feather—a wood or metal tool having a beveled edge and used to straighten re-entrant angles in finish plaster coat; also the edge of a concrete or mortar patch or topping that is beveled at an acute angle.
edge, pressed—edge of a footing along which the greatest soil pressure occurs under conditions of overturning.
edge-bar reinforcement—see reinforcement, edge-bar.
edge beam—see beam, edge.
edge form—see form, edge.
edger—a finishing tool used on the edges of fresh concrete to provide a rounded edge.
edging—the operation of tooling the edges of a fresh concrete slab to provide a rounded corner.
effective area of concrete—area of a concrete section assumed to resist shear or flexural stresses.
effective area of reinforcement—the area obtained by multiplying the right cross-sectional area of the metal reinforcement by the cosine of the angle between its centroidal axis and the direction for which its effectiveness is considered.
effective depth—see depth, effective.
effective flange width—see width, effective flange.
effective prestress—see prestress, effective.
effective span—see span, effective.
effective width of slab—that part of the width of a slab taken into account when designing T- or L-beams.
efflorescence—a deposit of salts, usually white, formed on a surface, the substance having emerged in solution from within either concrete or masonry and subsequently been precipitated by reaction, such as carbonation, or evaporation.
efflux time—time required for all grout to escape from a flow cone. (See also flow cone.)
elastic deformation—see deformation, elastic.
elastic design—see design, elastic.
elastic limit—see limit, elastic.
elastic loss—see loss, elastic.
elastic modulus—see modulus of elasticity (preferred term).
elasticity—that property of a material that enables it to return to its original size and shape after deformation.
elastomer—a macromolecular material that at room temperature returns rapidly to approximately its initial dimensions and shape after substantial deformation by a weak stress and removal of the stress; a term often used for rubber and polymers that have properties similar to those of rubber.
elastomeric—having the characteristics of an elastomer.
electrical curing—see curing, electrical.
electrical resistivity—a measure of the resistance of a material to flow of electric current.
electric log—a record or log of a borehole obtained by lowering electrodes into the hole and measuring any of the various electrical properties of the materials traversed.
electrochemical chloride extraction—corrosion passivation by removal of chlorides from concrete as a result of the application of a direct current that causes chlorides to migrate away from the reinforcing steel and out of the concrete.
electrochemical compatibility—see compatibility, electrochemical.
electrolysis—production of chemical changes by the passage of current through an electrolyte.
electrolyte—an ionically conducting medium in which the flow of charge is accompanied by movement of ions; usually an aqueous solution.
electrolytic cell—a unit apparatus in which electrochemical reactions are produced by applying electrical energy, or that supplies electrical energy as a result of chemical reactions and that includes two or more electrodes and one or more electrolytes contained in a suitable vessel.
elephant trunk—an articulated tube or chute used in concrete placement. (See also dropchute and tremie.)
elongated piece (of aggregate)—particle of aggregate for which the ratio of the length to the width of its circumscribing rectangular prism is greater than a specified value. (See also flat piece [of aggregate.])
elongation—increase in length. (See also expansion, shortening, and swelling.)
embedment length—see length, embedment.
embedment-length equivalent—the length of embedded reinforcement which can develop the same stress as that which can be developed by a hook or mechanical anchorage.
emery—a rock consisting essentially of an intercrystalline mixture of corundum and either magnetite or hematite; also manufactured aggregate composed of emery used to produce a wear-and slip-resistant concrete floor surface. (See also dry-shake.)
emulsion—a two-phase liquid system in which one liquid is immiscible in and uniformly dispersed throughout another liquid.
encastré—the end fixing of a built-in beam.
enclosure wall—see wall, enclosure.
encrustation—see incrustation (preferred term).
end anchorage—see anchorage, end.
end-bearing sleeve—device fitting over the abutting ends of two reinforcing bars for the purpose of assuring transfer of only axial compression from one bar to the other. (See also coupler; coupling sleeve; and mechanical connection.)
end block—see block, end.
endothermic reaction—see reaction, endothermic.
Engineer of record––an Engineer that is in responsible charge of the engineering evaluation, design, or other engineering responsibilities of a project.
entrained air—see air, entrained.
entrapped air—see air, entrapped.
epoxy—a thermosetting polymer that is the reaction product of epoxy resin and an amino hardener. (See also epoxy resin.)
epoxy-coated bar—see bar, epoxy-coated.
epoxy concrete—see concrete, epoxy.
envelope grouting—see grouting, envelope.
epoxy injection—a method for sealing or repairing cracks in concrete by injecting epoxy adhesives.
epoxy resins—see resins, epoxy.
equivalent alkalies, Na2Oeq—in hydraulic cement, the total of sodium and potassium oxides as calculated from the chemical analysis, and using the formula: Na2Oeq = % Na2O + 0.658 × % K2O.
equivalent rectangular stress-distribution—an assumption of uniform stress on the compression side of the neutral axis in the strength method of design to determine flexural capacity.
erosion—progressive disintegration of a solid by the abrasive or cavitation action of gases, fluids, or solids in motion. (See also abrasion damage and cavitation damage.)
ester—a class of compounds formed by the reaction of alcohols and organic acids.
ettringite—a mineral, high-sulfate calcium sulphoaluminate, occurring in nature or formed by sulfate attack on mortar or concrete.
evaluation—the process of assessing the need for maintenance, repair, or rehabilitation of concrete and concrete structures by determining in-situ condition and identifying the cause and extent of distress or deterioration; the process may include field and laboratory testing and engineering calculations. (See also condition assessment; condition survey; and visual inspection.)
evaporable water—see water, evaporable. (See also water, non-evaporable.)
evaporation retardant—a long-chain organic material such as cetyl alcohol which when spread on a water film on the surface of concrete retards the evaporation of bleed water. (See also monomolecular.)
exfoliation—disintegration occurring by scaling or peeling off in successive layers, swelling up and opening into leaves or plates like a partly opened book.
exotherm—heat released during a chemical reaction.
exothermic reaction—see reaction, exothermic.
expanded blast-furnace slag—see blast-furnace slag.
expanded-metal fabric reinforcement—see lath, expanded-metal.
expanded-metal lath—see lath, expanded-metal.
expanded shale (clay or slate)—see shale, expanded.
expanding cement—see cement, expansive.
expansion—increase in either length of volume. (See also contraction; moisture movement; shrinkage; volume change; and volume change, autogenous.)
expansion anchors—see anchor, expansion.
expansive cement—see cement, expansive.
expansive-cement concrete (mortar or grout)—see concrete (mortar or grout) and expansive cement.
expansive-cement mortar—see concrete (mortar or grout) and expansive cement.
expansive hydraulic cement—a hydraulic cement that forms a paste when mixed with water, and increases in volume a controlled amount during the early hardening period occurring after setting.
expansive component—see component, expansive.
explosive blasting—a method for fracturing and removing concrete with rapidly expanding gas confined within a series of bore holes; a cost effective and expedient means for removing large quantities of concrete.
exposed-aggregate finish—see finish, exposed-aggregate.
extender—a finely divided inert mineral or coarse aggregate added to provide economical bulk in synthetic resins and adhesives or cementitious mortars.
extensibility—the maximum tensile strain that hardened cement paste, mortar, or concrete can sustain without formation of a continuous crack.
extensometer points—an arrangement of three embedded plugs or surface-mounted discs, two on one side of a crack and the third on the other, which, when used in combination with a mechanical strain gage, provides a technique for monitoring crack width.
external strengthening—see strengthening, external.
external vibrator—see vibrator.
exudation—a liquid or viscous gel-like material discharged through a pore, crack, or opening in the surface of concrete.