Concrete Terminology » T

T & G—see tongue and groove.

table, flow—a flat, circular jigging device used in making flow tests for consistency of cement paste, mortar, or concrete. (See also flow, [2]).

tacky—the sticky condition of an adhesive prior to hardening.

talc—a mineral with a greasy or soapy feel, very soft, having the composition Mg3Si4O10(OH)2. (See also cement, masonry and Mohs scale.)

tamp process—see process, tamp.

tamper—(1) an implement used to consolidate concrete or mortar in molds, forms, or repair cavities. (2) a hand-operated device for consolidating floor topping or other unformed repair materials by impact from the dropped device in preparation for strikeoff and finishing; contact surface often consists of a screen or a grid of bars to force coarse aggregates below the surface to prevent interference with floating or troweling. (See also jitterbug.)

tamping—the operation of consolidating freshly placed concrete or other repair materials by repeated blows or penetrations with a tamper. (See also consolidation and rodding.)

tamping rod—see rod, tamping.

tangent modulus—see modulus of elasticity.

T-beam—a beam composed of a stem and a flange in the form of a T.

telltale—any device designed to indicate movement of formwork or of a point on the longitudinal surface of a pile under load.

temper—to add water to a cementitious mixture as necessary to initially bring the mixture to the desired workability. (See also retemper.)


temperature, glass-transition—the midpoint of the temperature range over which an amorphous material (such as glass or a high polymer) changes from (or to) a brittle, vitreous state to (or from) a plastic state.

temperature, heat-deflection—the temperature at which a plastic material has an arbitrary deflection when subjected to an arbitrary load and test condition; this is an indication of the glass-transition temperature.

temperature, steel—see reinforcement, temperature.

temperature cracking—see cracking, temperature.

temperature reinforcement—see reinforcement, temperature.

temperature rise—the increase of temperature caused by either absorption of heat or internal generation of heat, e.g., hydration of cement in concrete.

temperature stress—see stress, temperature.

template—a thin plate or board frame used as a guide in positioning or spacing form parts, reinforcement, or anchors; also a full-size mold, pattern, or frame, shaped to serve as a guide in forming or testing contour or shape.

temporary bracing––temporary supplemental members added to an existing structure to prevent local or global instability during evaluation and repair construction.

temporary stress—see stress, temporary.

tendon—a steel element, such as wire, cable, bar, rod, strand, or a bundle of such elements, primarily used in tension to impart compressive stress to concrete and as external strengthening to increase structural capacity.

tendon, bonded—a prestressing tendon that is bonded to the concrete through grouting or other approved means and; therefore, not free to move relative to the concrete.

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

tendon, unbonded—a tendon that is permanently free to move relative to the concrete being stressed.


tendons, concentric— tendons following a line coincident with the gravity axis of the prestressed-concrete member.

tendons, concordant—tendons, in statically indeterminate structures, that are coincident with the pressure line produced by the tendons; such tendons do not produce secondary moments.

tendons, deflected—tendons that have a trajectory that is curved or bent with respect to the gravity axis of the concrete member.

tendons, draped—see tendons, deflected.

tendons, harped—see tendons, deflected.

tendons, nonconcordant—in statically indeterminate structures, tendons, the center of gravity of which is not coincident with the pressure line due to prestressing alone. (See also cap cables.)

tendon profile—the path or trajectory of the prestressing tendon.

tensile bond strength—see strength, tensile bond.

tensile pull-off test—see test, tensile pull-off.

tensile strength—see strength, tensile.

tensile strength, splitting—tensile strength of concrete determined by a splitting tensile test.

tensile stress—see stress.

tension, diagonal—the principal tensile stress resulting from the combination of normal and shear stresses acting upon a structural element.

tension reinforcement—see reinforcement, tension.

terrazzo concrete—see concrete, terrazzo.

tesserae—small pieces of glass or marble tile used in mosaics.

test—a trial, examination, observation, or evaluation used as a means of measuring either a physical or a chemical characteristic of a material, or a physical characteristic of either a structural element or a structure.

test, air-permeability—a procedure for measuring the fineness of powdered materials such as portland cement.

test, Atterberg—a method for determining the plasticity of soils.

test, ball—a test to determine the consistency of freshly mixed concrete by measuring the depth of penetration of a cylindrical metal weight with a hemispherical bottom. (See also kelly ball.)

test, Blaine—a method for determining the fineness of cement or other fine material on the basis of the permeability to air of a sample prepared under specified conditions.

test, compression—test made on a test specimen of mortar or concrete to determine the compressive strength; in the United States, unless otherwise specified, compression tests of mortars are made on 2 in. (50 mm) cubes and compression tests of concrete are made on cylinders 6 in. (152 mm) in diameter and 12 in. (305 mm) high.

test, hot-load—a test for determining the resistance to deformation or shear of a refractory material when subjected to a specified compressive load at a specified temperature for a specified time.

test, Los Angeles abrasion—test for abrasion resistance of concrete aggregates.

test, remolding—a test to measure remoldability.

test, slump—the procedure for measuring slump.

test, tensile pull-off—a test to determine the unit stress, applied in direct tension, required to separate a hardened repair material from the existing concrete substrate. The test may also be used to determine the maximum unit stress that the existing concrete substrate is capable of resisting under axial tensile loading and the near-surface tensile strength of a prepared surface.

testing machine—a device for applying test conditions and accurately measuring results.

tetracalcium aluminoferrite—a compound in the calcium aluminoferrite series, having the composition 4CaO.Al2O3.Fe2O3, abbreviated C4AF, that is usually assumed to be the aluminoferrite present when compound calculations are made from the results of chemical analysis of portland cement.

texture—the pattern or configuration apparent in an exposed surface, as in concrete and mortar, including roughness, streaking, striation, or departure from flatness.

texturing—the process of producing a special texture on either unhardened or hardened concrete.

T-head—in precast framing, a segment of girder crossing the top of an interior column; also the top of a shore formed with a braced horizontal member projecting on two sides forming a T-shaped assembly.

thermal compatibility—see compatibility, thermal.

thermal conductance—see conductance, thermal.

thermal conductivity—see conductivity, thermal.

thermal contraction—contraction caused by decrease in temperature.

thermal cutting—procedure for removal of concrete with thermal or powder lances that employ intense heat generated by the reaction between oxygen and powdered metals to melt a slot into concrete. (See also thermal lance.)

thermal diffusivity—see diffusivity, thermal.

thermal expansion—expansion caused by increase in temperature.

thermal shock—the subjection of a material or body to a rapid change in temperature that may be expected to have a potentially deleterious effect.

thermal lance—equipment for cutting concrete with intense heat generated by the reaction between oxygen and powdered metals. (See also thermal cutting.)

thermal movement—change of dimension of concrete or masonry resulting from change of temperatures. (See also contraction and expansion.)

thermal resistance—see resistance, thermal.

thermal shock—see shock, thermal.

thermal stress—see stress, temperature.

thermal volume change—see volume change, thermal.

thermocouple—two conductors of different metals joined together at both ends, producing a loop in which an electric current will flow when there is a difference in temperature between the two junctions.

thermography, infrared—see infrared thermography.

thermoplastic—a material that can be repeatedly softened by heating and hardened by cooling.

thermosetting—capable of assuming a rigid, fixed shape when cured by heat or other means.

thin-shell precast—precast concrete characterized by thin slabs and web sections. (See also construction, shell.)

thixotropy—the property of a material that enables it to acquire a lower viscosity when mechanically agitated and rapidly stiffen upon subsequent rest; a material having this property is termed thixotropic and can be placed vertically or horizontally without sagging during the curing process. (See also rheology.)

threaded anchorage—see anchorage, threaded.

tie— (1) loop of reinforcing bars encircling the longitudinal steel in columns; and(2)  a tensile unit adapted to holding concrete forms secure against the lateral pressure of unhardened concrete.

tie, form—a mechanical connection in tension used to prevent concrete forms from spreading due to the fluid pressure of fresh concrete.

tie bar—see bar, tie.

tie bar, deformed—see bar, tie.

tie rod—see tie, form and tieback.

tieback—a rod fastened to a deadman, a rigid foundation, or either a rock or soil anchor to prevent lateral movement of formwork, sheet pile walls, retaining walls, bulkheads, etc.

tied column—see column, tied.

tiers—see lifts (preferred term).

tilting mixer—see mixer, tilting.

tilt-up—a construction technique for casting concrete elements in a horizontal position at the jobsite and then tilting them to their final position in a structure.

time-dependent deformation—see deformation, time-dependent.

time, final setting—the time required for a freshly mixed cement paste, mortar, or concrete to achieve final set. (See also time, initial setting.)

time, initial setting—the time required for a freshly mixed cement paste, mortar, or concrete to achieve initial set. (See also time, final setting.)

time of haul—in production of ready-mixed concrete, the period from first contact between mixing water and cement until completion of discharge of the freshly mixed concrete.

time of set—see time of setting.

time of setting—(1) the time required for a freshly mixed cement paste, mortar, or concrete to achieve initial set (see set, initial) or; (2) the time required for a freshly mixed cement paste, mortar, or concrete to achieve final set (see set, final).

tobermorite—a mineral found in Northern Ireland and elsewhere, having the approximate formula Ca5Si6O16(OH)2.4H2O, identified approximately with the artificial product tobermorite (G) of Brunauer, a hydrated calcium silicate having a CaO:SiO2 ratio in the range 1.39 to 1.75 and forming minute layered crystals that constitute the principal cementing medium in portland-cement concrete; a mineral with 5 mols of lime to 6 mols of silica, usually occurring in plate-like crystals, which is easily synthesized at steam pressures of about 100 psi and higher; the binder in several properly autoclaved products.

tobermorite gel—see gel, tobermorite.

toenail—(1) an obliquely driven nail; and (2) to drive a nail at an angle.

tolerance—(1) the permitted variation from a given dimension or quantity; (2) the range of variation permitted in maintaining a specified dimension; and (3) a permitted variation from location or alignment.

tom—see shore (preferred term).

tongue and groove—a joint in which a protruding rib on the edge of one side fits into a groove in the edge of the other side; abbreviated “T & G.” (See also keyway.)

tolerance—the permissible deviation from a specified dimension, quantity, location or alignment.

tool, arrissing—a tool similar to a float, but having a form suitable for rounding an edge of freshly placed concrete.

tool, gutter—a tool used to give the desired shape and finish to concrete gutters.

tooling—the act of compacting and contouring a material in a joint.

top form—see form, top.

topping—(1) a layer of concrete, mortar, or other material placed to form a floor or surface on a concrete base; (2) a structural, cast-in-place surface for precast floor and roof systems; and (3) the mixture of marble chips and matrix that, when properly processed, produces a terrazzo surface.

topping, dry—see dry-shake (preferred term).

topping, monolithic—on flatwork: a higher quality, more serviceable topping course placed promptly after the base course has lost all slump and bleed water.

torque viscometer—see viscometer, torque.

torsional stress—see stress, torsional.

toughness—the property of matter that resists fracture by impact or shock.

tower—a composite structure of frames, braces, and accessories.


trajectory of prestressing force—see path of prestressing force.

transfer—the act of transferring the stress in prestressing tendons from the jacks or pretensioning bed to the concrete member.

transfer bond—see bond, transfer.

transfer length—see length, transfer (preferred term).

transfer strength—see strength, transfer.

transformed section—see section, transformed.

transit-mixed concrete—see concrete, transit-mixed.

transit-mixer—see mixer, truck.

translucent concrete—see concrete, translucent.

transmission length—see length, transfer.

transverse crack—see crack, transverse.

transverse joint—see joint, transverse.

transverse prestress—see prestress, transverse.

transverse reinforcement—see reinforcement, transverse.

transverse strength—see strength, flexural and modulus of rupture.

traprock—any of various fine-grained, dense, dark colored igneous rocks, typically basalt or diabase; also called q-“trap.”

trass—a natural pozzolan of volcanic origin found in Germany, namely, trachytic tuffs that are intensely altered by geologic processes.

traveler—an inverted-U-shaped structure usually mounted on tracks that permit it to move from one location to another to facilitate the construction of an arch, bridge, or building.

travertine—dense to irregularly porous, commonly stratified or banded calcium carbonate, either aragonite or calcite, formed by deposition from hot spring waters.

tremie—a pipe or tube through which concrete is deposited under water, having at its upper end a hopper for filling and a bail for moving the assemblage.

tremie concrete—see concrete, tremie.

tremie seal—the depth to which the discharge end of the tremie pipe is kept embedded in the fresh concrete that is being placed; a layer of tremie concrete placed in a cofferdam for the purpose of preventing the intrusion of water when the cofferdam is dewatered.

trench form (for cast-in-place concrete pipe)—the vertical sides and semicircular bottom of the trench shaped to provide full, firm, and uniform support for the lower 210 degrees of the pipe.

trial batch—see batch, trial.

triaxial compression test—a test in which a specimen is subjected to a confining hydrostatic pressure and then loaded axially to failure.

triaxial test—a test in which a specimen is subjected simultaneously to lateral and axial loads.

tricalcium aluminate—a compound having the composition 3CaOAl2O3, abbreviated C3A.

tricalcium silicate—a compound having the composition 3CaOSiO2, abbreviated C3S, an impure form of which (alite) is a main constituent of portland cement. (See also alite.)

trough, flow—a sloping trough used to convey concrete by gravity flow from either a truck mixer or a receiving hopper to the point of placement. (See also chute.)

trough mixer—see mixer, open-top.

trowel—a flat, broad-blade steel hand tool used in the final stages of finishing operations to impart a relatively smooth surface to concrete floors and other unformed concrete surfaces; also a flat triangular-blade tool used for applying mortar to masonry. (See also fresno trowel.)

trowel-applied—the placement of a repair where the material is transported and pressed into the prepared substrate using a trowel or similar tool.

trowel finish—see finish, trowel.

troweling—smoothing and compacting the unformed surface of materials by strokes of a trowel.

troweling machine—a motor driven device that operates orbiting steel trowels on radial arms from a vertical shaft.

truck, agitating—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 contents; designated “agitating lorry” in the UK.

truck-mixed concrete—see concrete, transit-mixed.

truck mixer—see mixer, truck.

true solution—one in which the components are 100% dissolved in the base solvent.

T-shore—a shore with a T-head.

tub mixer—see mixer, open-top (preferred term).

tube a manchette—a grout pipe perforated with rings of small holes at intervals of about 12 in. (305 mm). Each ring of perforations is enclosed by a rubber sleeve that fits tightly around the pipe to act as a one-way valve when used with an inner pipe containing two packer elements that isolate a stage for injection of grout.

tube-and-coupler shoring—a load-carrying assembly of tubing or pipe which serves as posts, braces, ties, a base supporting the posts, and special couplers that connect the uprights and join the various members.

tunnel lining—a structural system of concrete, steel, or other materials to provide support for a tunnel for exterior loads, to reduce water seepage, or to increase flow capacity.

turbidimeter—a device for measuring the particle-size distribution of a finely divided material by taking successive measurements of the turbidity of a suspension in a fluid.

turbidimeter fineness—the fineness of a material such as portland cement, usually expressed as total surface area in square centimeters per gram, as determined with a turbidimeter. (See also Wagner fineness.)

turbine mixer—see mixer, open-top (preferred term).

twin-twisted bar reinforcement—see reinforcement, twin-twisted bar.

two-stage curing—see curing, two-stage.

two-way reinforced footing—a footing having reinforcement in two directions generally perpendicular to each other.

two-way reinforcement—see reinforcement, two-way.

two-way system—see system, two-way.

Type I cement—see cement, normal (preferred term).

Type II cement—see cement, modified (preferred term).

Type III cement—see cement, high-early strength (preferred term).

Type IV cement—see cement, low-heat (preferred term).

Type V cement—see cement, sulfate-resistant (preferred term).