fabric, welded-wire a series of longitudinal and transverse wires arranged approximately at right angles to each other and welded together at all points of intersection.
fabric, woven-wire a prefabricated steel reinforcement composed of cold-drawn steel wires mechanically twisted together to form hexagonally shaped openings.
face, pilaster the form for the front surface of a pilaster parallel to the wall.
factor, bulking ratio of the volume of moist sand to the volume of the sand when dry.
factor, coarse-aggregate the ratio, expressed as a decimal, of the amount (mass or solid volume) of coarse aggregate in a unit volume of well-proportioned concrete to the amount of dry-rodded coarse aggregate compacted into the same volume (b/b0).
factor, durability (1) a measure of the change in a material property over a period of time as a response to exposure to a treatment that can cause deterioration, usually expressed as percentage of the value of the property before exposure; or
(2) in ASTM C666, a measure of the effects of freezing and thawing action on concrete specimens, in which resonant frequency of vibration is used as the property measured.
factor, flow see cone, flow.
factor, maturity a factor that is a function of the age of the concrete (hours or days) multiplied by the difference between the mean temperature of the concrete (degrees) during curing and a datum temperature below which hydration stops. (See also degree-hour.)
factor, phi (f) see factor, strength-reduction (preferred term).
factor, Philleo a distance, used as an index of the extent to which hardened cement paste is protected from the effects of freezing, so selected that only a small portion of the cement paste (usually 10%) lies farther than that distance from the perimeter of the nearest air void . (See also protected paste volume.)
factor, Powers spacing see factor, spacing (preferred term.)
factor, spacing an index related to the maximum distance of any point in a cement paste or in the cement paste fraction of mortar or concrete from the periphery of an air void; also known as Powers spacing factor. (See also factor, Philleo.)
factor, stiffness a measure of the stiffness of a structural member; for a prismatic member, it is equal to the ratio of the product of the moment of inertia of the cross section and the modulus of elasticity for the material to the length of the member.
factor, strength reduction capacity-reduction factor (in structural design); a number less than 1.0 (usually 0.65 to 0.90) by which the strength of a structural member or element (in terms of load, moment, shear, or stress) is required to be multiplied to determine design strength or capacity; the magnitude of the factor is stipulated in applicable codes and construction specifications for respective types of members and cross sections.
factor of safety the ratio of load, moment, or shear of a structural member at the ultimate to that at the service level.
factored load see load, factored.
failure, fatigue the phenomenon of rupture of a material, when subjected to repeated loadings, at a stress substantially less than the static strength.
fair-face concrete see concrete, fair-face.
false header see header.
false set see set, false.
falsework the temporary structure erected to support work in the process of construction; composed of shoring or vertical posting, formwork for beams and slabs, and lateral bracing. (See also centering.)
fascia a flat member or band at the surface of a building or the edge beam of a bridge; also exposed eave of a building.
fastener a device designed to attach, join, or hold two or more objects one to another in juxtaposition; commonly readily removed.
fatigue the weakening of a material by repeated or alternating loads.
fatigue failure see failure, fatigue.
fatigue strength see strength, fatigue.
faulting differential displacement of a slab or wall along a joint or crack. History
feather edge see edge, feather.
feed, pneumatic shotcrete delivery equipment in which material is conveyed by a pressurized air stream.
feed wheel see wheel, feed.
felite a name used to identify one form of the constituent of portland-cement clinker now know when pure as dicalcium silicate (2CaOΧSiO2). (See also alite, belite, and celite.)
ferrocement a composite structural material comprising thin sections consisting of cement mortar reinforced by a number of very closely spaced layers of steel wire mesh.
fiber a slender and greatly elongated solid material, generally with a length at least 100 times its diameter, that has properties making it desirable for use as reinforcement. History
fiber, equivalent diameter diameter of a circle having an area equal to the average cross-sectional area of a fiber.
fiber, extreme compression farthest fiber from the neutral axis on the compression side of a member subjected to bending.
fiber, extreme tension farthest fiber from the neutral axis on the tension side of a member subjected to bending.
fiber count the number of fibers in a unit volume of fiber-reinforced concrete.
fiber-reinforced concrete see concrete, fiber-reinforced.
fiber-reinforced polymer (FRP) a general term for a composite material comprising a polymer matrix reinforced with fibers in the form of fabric, mat, strands, or any other fiber form. (See composite.) History
fibrous concrete see concrete, fiber-reinforced.
field bending bending of reinforcing bars on the job rather than in a fabricating shop.
field concrete see concrete, field.
field-cured cylinders see cylinders, field-cured.
field-proportioned grout see grout, field-proportioned.
fill, porous see drainage fill.
(1) a finely divided, relatively inert material, such as pulverized limestone, silica, or colloidal substances, added to portland-cement, paint, resin, or other materials to reduce shrinkage, improve workability, reduce cost, or reduce density; or
(2) material used to fill an opening in a form. History
filler, joint compressible material used to fill a joint to prevent the infiltration of debris and provide support for sealants applied to the exposed surface.
fillet see strip, chamfer.
fin a narrow linear projection on a formed concrete surface, resulting from mortar flowing into spaces in the formwork; also a type of blade in a concrete mixer drum.
final curing see curing, final.
final prestress see stress, final.
final set see set, final.
final setting time see time, final setting.
final stress see stress, final.
fine aggregate see aggregate, fine.
fine-grained soil see soil, fine-grained.
fineness a measure of particle size.
fineness modulus see modulus, fineness.
finish the texture of a surface after consolidating and finishing operations have been performed.
finish, bush-hammer the finish on concrete surface obtained by means of a bush-hammer.
finish, broom the surface texture obtained by stroking a broom over freshly placed concrete. (See also surface, brushed.)
finish, exposed-aggregate a decorative finish for concrete work achieved by removing, generally before the concrete has fully hardened, the outer skin of mortar and exposing the coarse aggregate.
finish, float a rather rough, granular concrete surface texture obtained by finishing with a float.
finish, granolithic a surface layer of granolithic concrete which may be laid on a base of either fresh or hardened concrete.
finish, gun undisturbed final layer of shotcrete as applied from nozzle, without hand finishing.
finish, rubbed a finish obtained by using an abrasive to remove surface irregularities from concrete. (See also sack rub.)
finish, rustic or washed a type of terrazzo topping in which the matrix is recessed by washing before setting so as to expose the chips without destroying the bond between chip and matrix; a retarder is sometimes applied to the surface to facilitate this operation. (See also finish, exposed-aggregate.)
finish, swirl a nonskid texture imparted to a concrete surface during final troweling by keeping the trowel flat and using a rotary motion.
finish, trowel the smooth or textured finish of an unformed concrete surface obtained by troweling.
finish coat see coat, finish.
finish grinding see grinding, finish.
finish screens see screens, finish.
finishing leveling, smoothing, consolidating, and otherwise treating surfaces of fresh or recently placed concrete or mortar to produce desired appearance and service. (See also float and trowel.)
finishing machine see machine, finishing.
fire clay see clay, fire.
fire resistance see resistance, fire.
fired strength see strength, fired.
fired density see density, fired.
fishtail a wedge-shaped piece of wood used as part of the support form between tapered pans in concrete joist construction.
flange, compression the widened portion of an I, T, or similar cross-section beam that is shortened or compressed by bending under normal loads, such as the horizontal portion of the cross section of a simple span T-beam.
flame photometer see photometer, flame.
flash coat see coat, flash.
flash set see set, flash.
flashing a thin impermeable sheet, narrow in comparison with its length, installed as a cover to exclude water from exposed joints, at roof valleys, hips, roof parapets, or intersections of roof and chimney.
flat jack see jack, flat.
flat piece (of aggregate) one in which the ratio of the width to thickness of its circumscribing rectangular prism is greater than a specified value. [See also elongated piece (of aggregate).]
flat plate see plate, flat.
flat slab see slab, flat.
flatwork, concrete a general term applicable to concrete floors and slabs that require finishing operations.
flexible joint see joint; hinge, Mesnager, and joint, semiflexible.
flexible pavement see pavement, flexible.
flexural bond stress see bond, flexural stress.
flexural rigidity see rigidity, flexural.
flexural strength see strength, flexural.
flint a variety of chert. (See also chert.)
float (1) a circular shallow-pan attachment, often of 48 in. (1.2 m) diameter with a 3/4 in. (19 mm) high rim, for powered finishing equipment, typically used to impart a relatively smooth final finish to floors; (2) a shallow horizontal tray suspended behind paving equipment, dragged across the freshly placed concrete surface to improve closure, or smoothness, or both.
float, angle a finishing tool having a surface bent to form a right angle; used to finish reentrant angles.
float, bull a tool comprising a large, flat, rectangular piece of wood, aluminum, or magnesium usually 8 in. (200 mm) wide and 42 to 60 in. (1 to 1.50 m) long, and a handle 4 to 16 ft (1 to 5 m) in length used to smooth unformed surfaces of freshly placed concrete.
float, devils a wooden float with two nails protruding from the toe, used to roughen the surface of a brown plaster coat. (See also texturing.)
float, power see float, rotary (preferred term).
float, rotary a motor-driven revolving disc that smooths, flattens, and compacts the surface of concrete floors and floor toppings.
float finish see finish, float.
floating the operation of finishing a fresh concrete or mortar surface by use of a float, preceding troweling when that is to be the final finish.
(1) time-dependent irrecoverable deformation (see also creep and rheology);
(2) a measure of the consistency of freshly mixed concrete, mortar, or cement paste expressed in terms of the increase in diameter of a molded truncated cone specimen after jigging a specified number of times; or
(3) movement of uncured resin under gravity loads or differential pressure. History
flow, capillary flow of moisture through a capillary pore system, such as in concrete.
flow, plastic increase in concrete strain of members subject to constant stress and for decrease in concrete stress of members subject to constant strain; an obsolete term (see creep and stress relaxation.)
flow cone see cone, flow.
flow factor see cone, flow.
flow line detectable line on a concrete wall or column usually departing somewhat from horizontal, that shows where the concrete in one placement has flowed horizontally before succeeding placement has been made.
flow promoter see promoter, flow.
flow table see table, flow.
flow trough see trough, flow.
flowable consistency see consistency, flowable.
flowing concrete see concrete, flowing.
fluid consistency see consistency, fluid.
fluidifier an admixture employed in grout to decrease the flow factor without changing water content. (See also admixture, water-reducing.)
fluosilicate magnesium or zinc silico-fluoride used to prepare aqueous solutions sometimes applied to concrete as surface-hardening agents.
flush water see wash (or flush) water.
fly ash the finely divided residue that results from the combustion of ground or powdered coal and that is transported by flue gases from the combustion zone to the particle removal system.
flying forms see forms, flying.
foam, preformed foam produced in a foam generator prior to introduction of the foam into a mixer with other ingredients to produce cellular concrete. (See also concrete, cellular.)
foamed blast-furnace slag see blast-furnace slag (2).
foamed concrete see concrete, foamed.
fog curing see curing, fog.
fog room see moist room.
folded plate see plate, folded.
footing a structural element of a foundation that transmits loads directly to the soil. History
footing, combined a structural unit or assembly of units supporting more than one column.
footing, continuous a combined footing of prismatic or truncated shape, supporting two or more columns in a row.
footing, sloped a footing having sloping top or side faces.
footing, stepped a step-like support consisting of prisms of concrete of progressively diminishing lateral dimensions superimposed on each other to distribute the load of a column or wall to the subgrade.
footing, strip see footing, continuous.
force, jacking in prestressed concrete, the temporary force exerted by the device which introduces tension into the tendons.
form a temporary structure or mold for the support of concrete while it is setting and gaining sufficient strength to be self-supporting. (See also formwork.)
form, climbing a form which is raised vertically for succeeding lifts of concrete in a given structure.
form, drop-panel a retainer or mold so erected as to give the necessary shape, support, and finish to a drop panel.
form, edge formwork used to limit the horizontal spread of fresh concrete on flat surfaces such as pavements or floors.
form, permanent any form that remains in place after the concrete has developed its design strength; it may or may not become an integral part of the structure.
form, sliding see slipform.
form, top form required on the upper or outer surface of a sloping slab or thin shell.
form, vented a form so constructed as to retain the solid constituents of concrete and permit the escape of water and air.
form, wall a retainer or mold so erected as to give the necessary shape, support, and finish to a concrete wall.
form anchor see anchor, form.
form coating see coating, form.
form hanger see hanger, form.
form insulation see insulation, form.
form lining materials used to line the concreting face of formwork either to impart a smooth or patterned finish to the concrete surface, to absorb moisture from the concrete, or to apply a set-retarding chemical to the formed surface. (See also sheathing.)
form oil see oil, form.
form pressure see pressure, form.
form release agent see agent, release.
form scabbing inadvertent removal of the surface of concrete because of adhesion to the form.
form sealer coating applied to the surface of a form to reduce or prevent absorption of water from the concrete.
form spacer see spacer, see also spreader.
form spreader see spreader.
form tie see tie, form.
forms, flying large prefabricated units of formwork incorporating support, and designed to be moved from place to place.
forms, ganged prefabricated panels joined to make a much larger unit (up to 30 by 50 ft) (9 by 15 m) for convenience in erecting, stripping, and reusing; usually braced with wales, strongbacks, or special lifting hardware.
forms, moving large prefabricated units of formwork incorporating supports, and designed to be moved horizontally on rollers or similar devices, with a minimum amount of dismantling between successive uses.
formwork total system of support for freshly placed concrete including the mold or sheathing that contacts the concrete as well as supporting members, hardware, and necessary bracing; sometimes called shuttering in the United Kingdom. (See also falsework and centering.)
foundation a system of structural elements that transmit loads from the structure above to the earth. History
foundation, grid a combined footing formed by intersecting continuous footings, loaded at the intersection points, and covering much of the total area within the outer limits of the assembly.
foundation, mat a foundation consisting of a continuous concrete slab extending in both directions that is usually reinforced and supports an array of columns and/or walls. Also referred to as foundation, raft. History
foundation, raft see foundation, mat. History
foundation, strip a continuous foundation wherein the length considerably exceeds the breadth.
foundation bolt see bolt, anchor (preferred term).
four-way reinforcement see reinforcement, four-way.
fracture a crack or break, as of concrete or masonry; the configuration of a broken surface; also the action of cracking or breaking. (See also crack.)
frame, rigid a frame depending on moment in joints for stability.
free fall descent of freshly mixed concrete into forms without dropchutes or other means of confinement; also the distance through which such descent occurs; also uncontrolled fall of aggregate.
free lime see lime, free.
free moisture see moisture, free.
free water see moisture, free. (See also moisture, surface.)
fresh concrete see concrete, fresh.
fresno trowel a thin steel trowel that is rectangular or rectangular with rounded corners, usually 4 in. to 10 in. (100 to 250 mm) wide and 20 in. to 36 in. (420 to 900 mm) long, having 4 ft to 16 ft (1 to 5 m) long handle, and used to smooth surfaces of nonbleeding concrete and shotcrete.
friction loss see loss, friction.
friction pile see pile, friction.
friction, wobble in prestressed concrete, the friction caused by the unintended deviation of the prestressing sheath or duct from its specified profile.
frog a depression in the bed surface of a masonry unit; sometimes called a panel.
fugitive dye a dye whose color fades in a few days to neutral on exposure, usually to ultraviolet rays in sunlight; used to temporarily color membrane-curing compounds so that coverage of the concrete surface can be observed.
Fuller-Thompson ideal grading curve see Fullers curve (preferred term).
Fullers curve an empirical curve for gradation of aggregates; also known as the Fuller-Thompson ideal gradation curve; the curve is designed by fitting either a parabola or an ellipse to a tangent at the point where the aggregate fraction is one-tenth of the maximum size fraction. (See also grading curve.)
furring strips of wood or metal fastened to a wall or other surface to even it, to form an air space, to give appearance of greater thickness, or for the application of an interior finish such as plaster.
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