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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.
strength of concrete or mortar usually as developed at various times duringthe first 72 hours after placement.
a tool designed to cut joints in concrete commencing 1 to 4 hours afterfinishing and without raveling the cut edges.
a prestressing tendon that follows a trajectory not coincident with the gravity axis of the concrete member.
a stiffening beam at the edge of a slab.
formwork used to limit the horizontal spread of fresh concrete on flat surfaces such as pavements or floors.
tensile reinforcement sometimes used to strengthen otherwise inadequate edges in a slab without resorting to edge thickening.
area of a concrete section assumed to resist shear or flexural stresses.
depth of a beam or slab section measured from the compression face to the centroid of the tensile reinforcement.
width of slab adjoining a beam stem where the slab is assumed to functionas the flange element of a T-beam section.
stress remaining in prestressing steel after all losses have occurred (alsocalled final prestress or final stress).
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.
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.
design based on a linear distribution of flexural stresses and strains andcorresponding limiting elastic properties of the material.
the limit of stress beyond which the strain is not wholly recoverable.
in prestressed concrete, the reduction in prestressing load resulting from the elastic shortening of the member.
in prestressed concrete, the shortening of a member that occurs immediately on the application of forces induced by prestressing.
that property of a material by virtue of which it tends to recover its original size and shape after deformation.
a system in which a favorable temperature is maintained in freshly placed concrete by supplying heat generated by electrical resistance.
an articulated tube or chute used in concrete placement. (See alsodropchute and tremie.)
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].)
increase in length. (See also expansion, elastic shortening, and swelling.)
the length of embedded reinforcement provided beyond a critical section.
a rock consisting essentially of an intercrystalline mixture of corundum and either magnetite or hematite. (See also dry-shake.)
designing precast elements and their structural connections to perform as if the structure was a conventional cast-in-place concrete structure.
(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
an enlarged end section of a member intended to reduce anchorage stresses to allowable values and provide space needed for post-tensioning anchorages.
a chemical reaction that occurs with the absorption of heat.
see architect-engineer.
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.)
air voids incorporated into concrete during mixing that are mainly irregular in shape and usually 1 mm (0.04 in.) or larger in size.
a thermosetting polymer that is the reaction product of epoxy resin and an amino hardener. (See also epoxy resin.)
a mixture of epoxy resin and hardener, fine aggregate, and coarseaggregate. (See also polymer concrete, mortar, epoxy, and epoxy resin.)
a grout consisting of an epoxy bonding system, aggregate or fillers, andpossibly other materials.
a mixture of epoxy resin, hardener, and fine aggregate. (See also epoxyresin. )
a reinforcing bar coated with an epoxy resin.
the density reached by structural lightweight concrete after exposure to relative humidity of 50 ± 5 percent and a temperature of 73.5 ± 3.5°F (23± 2°C) for a period of time sufficient to reach a density that changes lessthan 0.5 percent in a period of
diameter of a circle having an area equal to the average cross-sectionalarea of a fiber.
an assumption of uniform stress on the compression side of the neutralaxis in the strength design method to determine flexural capacity.
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.)
(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.
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.)
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.)
disintegration occurring by peeling off in successive layers, swelling up and opening into leaves or plates like a partly opened book.
a chemical reaction that occurs with the evolution of heat.
lightweight vesicular aggregate obtained by firing suitable raw materials ina rotary kiln or on a sintering grate under controlled conditions.
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.)
increase in either length or volume. (See also shrinkage, volume change, and autogenous volume change.)
(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
a tubular metal covering for a dowel bar to allow its free longitudinal movement at a joint.
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
the portion of an expansive cement that is responsible for the expansion, generally one of several anhydrous calcium aluminate or sulfoaluminate compounds and a source of sulfate, with or without free lime (CaO).
a decorative finish for concrete work achieved by removing, generally before the concrete has hardened, the outer skin of mortar and exposing the coarse aggregate.
designation used to describe environmental conditions to which concrete will be exposed.
that property by virtue of which a material can undergo extension or elongation following the application of force.
in a flat slab, a panel having at least one edge that is not in common withanother panel.
farthest fiber from the neutral axis on the compression side of a membersubjected to bending.
farthest fiber from the neutral axis on the tension side of a membersubjected to bending.
a liquid or viscous gel-like material discharged through a pore, crack, or opening in the surface of concrete.
