Concrete Waterproofing Glossary

Early Age (of Concrete)

the period after final setting during which properties are changing rapidly.

the early development of an abnormal reduction in the working characteristics of a hydraulic-cement paste, mortar, or concrete, which may be further described as false setting, quick setting, or flash setting.

Early Strength

strength of concrete or mortar usually as developed at various times duringthe first 72 hours after placement.

Early-entry Dry Cut Saw

a tool designed to cut joints in concrete commencing 1 to 4 hours afterfinishing and without raveling the cut edges.

Eccentric Tendon

a prestressing tendon that follows a trajectory not coincident with the gravity axis of the concrete member.

Edge Beam

a stiffening beam at the edge of a slab.

Edge Form

formwork used to limit the horizontal spread of fresh concrete on flat surfaces such as pavements or floors.

Edge Reinforcement

tensile reinforcement sometimes used to strengthen otherwise inadequate edges in a slab without resorting to edge thickening.

Effective Area of Concrete

area of a concrete section assumed to resist shear or flexural stresses.

Effective Depth

depth of a beam or slab section measured from the compression face to the centroid of the tensile reinforcement.

Effective Flange Width

width of slab adjoining a beam stem where the slab is assumed to functionas the flange element of a T-beam section.

Effective Prestress

stress remaining in prestressing steel after all losses have occurred (alsocalled final prestress or final stress).

Effective Span

the lesser of the two following distances: (a) the distance between supports; (b) the clear distance between supports plus the effective depth of the beam or slab.

Efflorescence

a generally white deposit formed when water-soluble compounds emerge in solution from concrete, masonry, or plaster substrates and precipitate by reaction such as carbonation or crystallize by evaporation.

Elastic Design

design based on a linear distribution of flexural stresses and strains andcorresponding limiting elastic properties of the material.

Elastic Limit

the limit of stress beyond which the strain is not wholly recoverable.

Elastic Loss

in prestressed concrete, the reduction in prestressing load resulting from the elastic shortening of the member.

Elastic Shortening

in prestressed concrete, the shortening of a member that occurs immediately on the application of forces induced by prestressing.

Elasticity

that property of a material by virtue of which it tends to recover its original size and shape after deformation.

Electrical Curing

a system in which a favorable temperature is maintained in freshly placed concrete by supplying heat generated by electrical resistance.

Elephant Trunk

an articulated tube or chute used in concrete placement. (See alsodropchute 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, elastic shortening, and swelling.)

Embedment Length

the length of embedded reinforcement provided beyond a critical section.

Emery

a rock consisting essentially of an intercrystalline mixture of corundum and either magnetite or hematite. (See also dry-shake.)

Emulation

designing precast elements and their structural connections to perform as if the structure was a conventional cast-in-place concrete structure.

End Anchorage

(1) length of reinforcement, mechanical anchor, hook, or combination thereof, beyond the point of nominal zero stress in the reinforcement ofcast-in-place concrete;
(2) mechanical device to transmit prestressing force to the concrete in a post-tensioned

End Block

an enlarged end section of a member intended to reduce anchorage stresses to allowable values and provide space needed for post-tensioning anchorages.

Endothermic Reaction

a chemical reaction that occurs with the absorption of heat.

Engineer-architect

see architect-engineer.

Entrained Air

microscopic air bubbles intentionally incorporated in mortar or concrete during mixing, usually by use of a surface-active agent; typically between10 m m (0.004 in.) and 1 mm (0.04 in.) in diameter and spherical or nearlyso. (See also air entrainment.)

Entrapped Air

air voids incorporated into concrete during mixing that are mainly irregular in shape and usually 1 mm (0.04 in.) or larger in size.

Epoxy

a thermosetting polymer that is the reaction product of epoxy resin and an amino hardener. (See also epoxy resin.)

Epoxy Concrete

a mixture of epoxy resin and hardener, fine aggregate, and coarseaggregate. (See also polymer concrete, mortar, epoxy, and epoxy resin.)

Epoxy Grout

a grout consisting of an epoxy bonding system, aggregate or fillers, andpossibly other materials.

Epoxy Mortar

a mixture of epoxy resin, hardener, and fine aggregate. (See also epoxyresin. )

Epoxy-coated Bar

a reinforcing bar coated with an epoxy resin.

Equilibrium Density

the density reached by structural lightweight concrete after exposure to relative humidity of 50 Â± 5 percent and a temperature of 73.5 Â± 3.5°F (23Â± 2°C) for a period of time sufficient to reach a density that changes lessthan 0.5 percent in a period of

Equivalent Fiber Diameter

diameter of a circle having an area equal to the average cross-sectionalarea of a fiber.

Equivalent Rectangular Stress Distribution

an assumption of uniform stress on the compression side of the neutralaxis in the strength design method to determine flexural capacity.

Erosion

progressive loss of material from a solid surface due to a mechanicalinteraction between that surface and a fluid, a multi-component fluid,or solid particles carried with the fluid. (See also abrasion damage andcavitation damage.)

Ettringite

(1) a mineral, high-sulfate calcium sulfoaluminate(3CaO – Al 2 O 3 – 3CaSO 4 – 30-32H 2 O), occurring in nature or formed by sulfate attack on mortar and concrete;
(2) the product of the principal expansion- producing reaction in expansive cements.

Evaporable Water

water in set cement paste present in capillaries or held by surface forces; measured as that removable by drying under specified conditions. (See also nonevaporable water.)

Evaporation Retardant

a material applied to the surface of concrete before initial setting to reduce the evaporation rate of water without interfering with finishing operations (also called evaporation reducer). (See also monomolecular.)

Exfoliation

disintegration occurring by peeling off in successive layers, swelling up and opening into leaves or plates like a partly opened book.

Exothermic Reaction

a chemical reaction that occurs with the evolution of heat.

Expanded Shale (clay Or Slate)

lightweight vesicular aggregate obtained by firing suitable raw materials ina rotary kiln or on a sintering grate under controlled conditions.

Expanded-metal Lath

a metal network, often used as reinforcement in construction, formed by suitably stamping or cutting sheet metal and stretching it to form open meshes, either of diamond-shaped or rhomboidal-shaped openings. (See also diamond mesh.)

Expansion

increase in either length or volume. (See also shrinkage, volume change, and autogenous volume change.)

Expansion Joint

(1) a separation provided between adjacent sections of a concrete structure to allow movement due to dimensional increases and reductions of the adjacent sections and through which some or all of the bonded reinforcement is interrupted;
(2) a separation

Expansion Sleeve

a tubular metal covering for a dowel bar to allow its free longitudinal movement at a joint.

Expansive Cement

a cement that when mixed with water produces a paste that after setting increases in volume to a greater degree than does portland-cement paste.
(1) Type K expansive cement – a mixture of portland cement, anhydrous tetracalcium trialuminate sulfate (C4A3S