Construction Terms & Definitions
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Common constrction terms.
macrocell corrosion - process whereby one layer of metallic reinforcement corrodes preferentially to another layer. (See also microcell corrosion.)
magnesium phosphate cement - a rapid-setting cement that can be used at low temperatures.
maintenance - taking periodic actions that will delay damage or deterioration or both. (See also
preservation and protection.)
manifold - see grout header.
map cracking - generally orthogonal cracks that extend below the surface of a hardened material; caused by a restrained decrease in volume of the material near the surface, such as drying shrinkage of cementitious materials, the restraint being provided by the material at greater depths where minimal shrinkage occurs or by a previously existing substrate. (See also checking, crazing, and pattern cracks.)
mastic - a thick adhesive material used to hold waterproofing membranes in place or as a sealant.
mat - a fibrous reinforcing material composed of chopped filaments (for chopped-strand mats) or swirled filaments (for continuous-strand mats) with a binder applied to maintain form; available in blankets of various widths, weights, thicknesses, and lengths.
match - to provide, by selection, formulation, adjustment, or other means, a surface repair that is indistinguishable from or within specified tolerances of the surrounding area.
material hose - see delivery hose.
matrix - (1) in the case of mortar, the cement paste in which the fine aggregate particles are embedded; in the case of concrete, the mortar in which coarse aggregate particles are embedded; (2) in the case of fiber-reinforced composites, the material in which the fiber reinforcements are embedded.
mechanical anchors - see expansion anchors.
mechanical bond - in general concrete construction, the physical interlock between cement paste and aggregate, or between concrete and reinforcement (specifically, the sliding resistance of an embedded bar and not the adhesive resistance).
mechanical properties - those properties of a material that are associated with elastic and inelastic reaction when force is applied, or which involve the relationship between stress and strain.
mechanical shearing - a method for removal of concrete and steel with hydraulically powered jaws; especially applicable for demolition work. (See also jaw crusher.)
membrane - protective surface treatment with a thickness greater than 30 mils (0.75 mm) and less than 250 mils (6 mm) applied to the surface of concrete.
membrane, liquid - a liquid material applied to a surface to form a continuous waterproof film after it cures.
membrane, sheet - any functionally continuous flexible structure of felt, fabric, or mat, or combinations thereof, and plying cement.
membrane curing - a process that involves either liquid sealing compound or nonliquid protectivecoating, both of which function as films to restrict evaporation of mixing water from cementitious repair materials.
metering pump - a device incorporating one or more pumps for pressurizing and delivering fluids such as grout; for multi-component materials, the flow rates of the pumps are synchronized to dispense the components at the desired ratio.
methacrylate - one of a group of resins formed by polymerizing the esters or amides of acrylic acids.
methyl methacrylate - a colorless, volatile liquid derived from acetone cyanohydrin, methanol, and dilute sulfuric acid.
microcell corrosion - localized corrosion in which anodic and cathodic reaction sites are in close proximity to one another. (See also macrocell corrosion.)
microcrack - a crack too small to be seen with the unaided eye.
microsilica - see silica fume.
mil - one thousandth of an inch, 0.001 in. (0.0254 mm); typically used as the unit of measurement for thickness of thin coatings.
mildew - a superficial growth produced by fungi in the presence of moisture that causes surface discoloration and decomposition.
milling - method commonly used for removal of a specified depth of concrete from large areas ofhorizontal or vertical surfaces. (See also scarifier.)
mineral filler - a finely divided mineral product at least 65 percent of which passes the U. S. Standard 75-µm (No. 200) sieve.
minimum-film-forming temperature - the lowest temperature at which latex will coalesce to form a continuous film.
mist - a process in which a very fine spray of water is applied to, (a) a fresh concrete surface to minimize the potential for plastic shrinkage cracking, or (b) a hardened concrete surface for moist curing.
mix - to combine or blend two or more materials into a single mixture; a compound of two or more materials.
mixer - a machine used for blending the constituents of concrete, grout, mortar, cement paste, or other mixture.
mixing speed - rotation rate of a mixer drum or of the paddles in an open-top, pan, or trough mixer, when mixing a batch.
mixing time - the time from completion of mixer charging until the beginning of discharge.
mixture - the assembled and blended ingredients of cementitious repair materials or the proportions for their assembly.
modulus of elasticity - the ratio of normal stress to corresponding strain for tensile or compressive stress below the proportional limit of the material; also referred to as elastic modulus or Young's modulus.
modulus of rupture - a measure of the ultimate load-carrying capacity of a beam tested in flexure. (See also flexural strength.)
moisture content - the ratio, expressed as a percentage, of the mass of absorbed or adsorbed water in a given material to the total mass.
moisture movement - the movement of moisture through a porous medium. (See also shrinkage and swelling.)
monolithic repair - a repair system wherein the individual components react together as a uniform, continuous mass.
monomer - an organic liquid, of relatively low molecular weight, that creates a solid polymer by reacting with itself or other compounds of low molecular weight or both.
mortar - a mixture of cement paste and fine aggregate.
mortar, polymer - a composite material of fine aggregates bound together by an organic polymer.
mottled - adjacent spots of different tones and colors in a coating film that create a blotchy effect.
mudcracking - a coating defect characterized by a broken network of cracks in the surface film.
mudjacking - see slabjacking.
neat cement grout - a mixture of hydraulic cement and water.
neat cement paste - a mixture of hydraulic cement and water.
necking - the change in cross-sectional area of a material as it elongates.
needle scaling - a surface preparation method in which the surface is impacted with the pointed tips of a bundle of steel rods contained by a steel tube and pulsed by compressed air.
negative side waterproofing - applying waterproofing to the side of a structural element opposite the one subjected to hydrostatic pressure.
neoprene - an elastomer, polychloroprene, formed by adding hydrogen chloride to monovinylacetylene.
nondestructive testing - examination of materials and structures in ways that do not impair futureusefulness and serviceability in order to detect, locate, and measure discontinuities, defects, and other imperfections to assess integrity, properties, and uniformity, and to measure geometrical characteristics.
non-evaporable water - the water that is chemically combined during cement hydration; not removable by specified drying. (See also evaporable water.)
nozzle - an open-ended metal or rubber tip attached to the discharge end of a shotcrete nozzle body.
nozzle body - a device at the end of a shotcrete delivery hose that contains a regulating valve and amanifold for adding water or air to the shotcrete mixture.
nozzle liner - a rubber lining placed inside the nozzle tip to provide abrasion protection.
nozzleman - the operator who manipulates the nozzle and controls placement of the shotcrete; in the case of dry-mix shotcrete, the operator also controls the water content of the shotcrete.
nozzle velocity - the rate at which shotcrete is ejected from the nozzle.
opacity - the ability of a surface-applied coating to obliterate or hide the color of the surface to which it is applied.
open-circuit grouting - a grouting system with no provision for recirculation of grout to the pump.
orange peel - the dimpled appearance of a dried surface-applied coating that resembles the peel of an orange.
osmosis - the diffusion of a solvent or of a dilute liquid through a skin (permeable in only one direction) into the more concentrated solution.
outgassing - the upward and outward emission of air or moisture vapor from concrete or mortar.
overbreak - the quantity of material that is excavated or breaks out beyond the perimeter of a specific removal area.
overlay - a bonded or unbonded layer of material placed on a concrete surface to either restore or improve the function of the previous surface.
overspray - (1) in protective coatings, any material not deposited within the surface area specified for coating. (2) in shotcreting, material deposited away from the intended receiving surface.
oxidize - to unite with oxygen; cause the oxidation of; rust.
pachometer - nondestructive testing device commonly used to detect and locate embedded reinforcing steel; the device emits an electromagnetic field and detects disturbances in the field caused by embedded metals.
packer - an expandable device inserted into a hole to be grouted that prevents the grout from flowing back around the injection pipe.
paddle mixer - a mixer consisting essentially of a trough within which mixing paddles revolve about the horizontal axis, or a pan within which mixing blades revolve about the vertical axis.
pargeting - to cover with plaster.
partial-depth repair - removal and replacement of damaged or deteriorated near-surface concrete that constitutes only a portion of the depth of a member or element.
particle size - the controlling lineal dimension of individual particles.
particulate grout - any grouting material characterized by undissolved (insoluble) particles in the mix. (See also chemical grout.)
pass - one movement over an area; a layer of material placed in one movement over an area.
passivation - the process in metal corrosion by which metals become passive. (See also passive.)
passive - the state of a metal surface characterized by low corrosion rates in a potential region that is strongly oxidizing for the metal.
pattern cracks - see craze cracks, map cracking.
pea gravel - screened gravel, most of the particles of which pass a 9.5-mm (_ in.) sieve and are retained on a 4.75-mm (No. 4) sieve.
peeling - a process in which thin flakes of mortar are broken away from a concrete surface, such as by deterioration or by adherence of surface mortar to forms as forms are removed.
penetrability - a grout property descriptive of its ability to fill a porous mass; primarily a function of lubricity and viscosity.
penetration grouting - filling joints or fractures in rock or pore spaces in soil with a grout without disturbing the formation; this grouting method does not modify the solid formation structure. (See also
penetration probe - a device for obtaining a measure of the resistance of concrete to penetration;customarily determined by the distance that a steel pin is driven into the concrete from a special gun by a precisely measured explosive charge.
penetrating sealer - material that has the ability to penetrate and seal the surface to which it is applied. (See also sealing compound.)
percussion drilling - a drilling process in which a hole is advanced by using a series of impacts to the drill steel and attached bit; the bit is normally rotated during drilling. (See also rotary drilling.)
perimeter grouting - injection of grout, usually at relatively low pressure, around the periphery of an area which is subsequently to be grouted at greater pressure; intended to confine subsequent grout injection within the perimeter.
perm - the mass rate of water vapor flow through one square foot of a material or construction of one grain per hour induced by a vapor pressure gradient between two surfaces of one inch of mercury or in units that equal that flow rate.
permanent set - inelastic elongation or shortening.
permeability - the property of porous material that permits a fluid (or gas) to pass through it; in construction, commonly refers to water vapor permeability of a sheet material or assembly and is defined as water vapor permeance per unit thickness. (See also water vapor transmission, perm, and permeance.)
permeability to water, coefficient of - the rate of discharge of water under laminar flow conditions through a unit cross-sectional area of a porous medium under a unit hydraulic gradient and standard temperature conditions, usually 20 C.
permeance (water vapor) - the ratio of the rate of water vapor transmission through a material orassembly between its two parallel surfaces to the vapor pressure differential between the surfaces.
permeation grouting - filling joints or fractures in rock or pore spaces in soil with a grout, without disturbing the formation.
petrographic examination - methods of examining nonmetallic matter under suitable microscopes to determine structural relationships and to identify the phases or minerals present; with opaque materials, the color, hardness, reflectivity, shape, and etching behavior in polished sections serve as means of identification.
pH - a measure of the dity or alkalinity of a solution, with neutrality represented by a value of 7, with increasing acidity represented by increasingly smaller values and with increasing alkalinity represented by increasingly larger values.
pigment - an insoluble fine powder mixed with water, oil, or other base that creates color.
pinhole - a coating defect characterized by minute holes through a coating that exposes the underlying substrate.
pitting - development of relatively small surface cavities, such as popouts in concrete or corrosion of steel.
plng - the deposition, distribution, and consolidation of a freshly mixed concrete repair material in the place where it is to harden.
plane of weakness - the plane along which a composite repair system tends to fracture.
plastic shrinkage - shrinkage that occurs prior to setting of a cementitious repair material.
plastic shrinkage cracks - cracking that occurs in the surface of a fresh cementitious repair material soon after it is placed and while it is still plastic.
plasticizer - (1) a material that increases the plasticity of a fresh cementitious repair material. (2) asubstance added to an adhesive to increase softness, flexibility, and extensibility. (3) a substance added to polymer or copolymer to reduce its minimum film forming temperature or its glass transition temperature.
pneumatic feed - equipment that uses compressed air to deliver shotcrete.
pneumatically applied mortar - see shotcrete.
polishing - (1) abrasion of wearing course aggregates caused by traffic loads and the environment. (2) the use of abrasives to smooth a surface.
polyester - one of a group of resins, mainly produced by reaction of dibasic acids with dihydroxy alcohols; commonly dissolved in a vinyl group monomer such as styrene; used as binders for resinmortars and concretes, fiber laminates (mainly glass), adhesives, and the like. (See also concrete, polymer.)
polyethylene - a thermoplastic high-molecular-weight organic compound used in formulating protective coatings or, in sheet form, as a protective cover for concrete repairs during the curing period.
polymer - the product of polymerization; more commonly a rubber or resin consisting of large molecules formed by polymerization.
polymer-modified concrete - see concrete, polymer-modified.
polymer concrete - see concrete, polymer.
polymer mortar - see mortar, polymer.
polymer mortar, conductive - see conductive-polymer mortar.
polymerization - a chemical reaction in which monomers are linked together to form polymers.
polyolefin fiber - a manufactured fiber in which the fiber-forming substance is any long-chain synthetic polymer composed of at least 85 percent by weight of ethylene, propylene, or other olefin units, except amorphous (noncrystalline) polyolefins.
polypropylene - highly chemically inert, long-chain synthetic polymer; fibrillated and monofilament fibers for concrete reinforcement.
polysulfide - synthetic polymers obtained by the reaction of sodium polysulfide with organic dichlorides.
polyurethane - reaction product of an isocyanate with any of a wide variety of other componentscontaining an active hydrogen group; used to formulate tough, abrasion-resistant coatings.
polyvinyl acetate - colorless, permanently thermoplastic resin; usually supplied as an emulsion or water-dispersible powder characterized by flexibility, stability towards light, transparency to ultraviolet rays, high dielectric strength, toughness, and hardness.
popout - the breaking away of small portions of a concrete surface due to localized internal pressure which leaves a shallow, typically conical, depression; small popouts leave holes up to 10 mm in diameter, medium popouts leave holes 10 to 50 mm in diameter, large popouts leave holes greater than 50 mm in diameter.
pore - a discontinuity, essentially circular in cross section, in a coating extending through to theunderlying coating or the basis material.
porosity - the ratio the volume of all voids in a material to the volume of the whole.
port - see injection port.
port adapter - device used to connect an injection hose to a crack or void; may be attached to theconcrete surface along a crack or inserted in holes drilled into the concrete.
portland cement - see cement, portland.
positive displacement - equipment that uses a piston or auger to push a solid mass of wet-mix shotcrete through the delivery hose.
positive side waterproofing - applying waterproofing material to the side of a structural element subjected to hydrostatic pressure.
potable water - water that is safe for drinking.
pot life - time interval after mixing, during which a liquid material can be applied without difficulty.
powder lance - equipment for cutting concrete with intense heat generated by the reaction betweenoxygen and powdered metals.
pozzolan - a siliceous or siliceous and aluminous material, which in itself possesses little or no cementitious value but will, in finely divided form and in the presence of moisture, chemically react with calcium hydroxide at ordinary temperatures to form compounds possessing cementitious properties.
practical coverage - the spreading rate of a coating calculated at the recommended dry film thickness and assuming 15 percent material loss.
preconditioning - any preliminary exposure of a material to the influence of specified atmosphericconditions for the purpose of favorably approaching equilibrium with a prescribed atmosphere.
predampening - adding water to aggregate that will be used in dry-mix shotcrete to bring the moisture content of the aggregate to a specified amount, usually 3 to 6 percent.
prepackaged - dry ingredients of grout, mortar, and concrete mixtures in packages, requiring only the addition of water to produce grout, mortar, or concrete.
prepacked concrete - see concrete, preplaced-aggregate.
preplaced-aggregate concrete - see concrete, preplaced-aggregate and concrete, colloidal.
preservation - the process of maintaining a structure in its present condition and arresting further deterioration. (See also maintenance and protection).
presplitting - a procedure in which hydraulic splitters, water pressure pulses, or expansive chemicals are ued in bore holes drilled at points along a predetermined line to induce a crack plane for the removal of concrete.
prewetting - adding a portion of the mixing water to dry-mix shotcrete materials in the delivery hose at some distance from the nozzle.
primer - the first coat of a material applied following surface preparation; serves to improve the bond of subsequent coats and may have corrosion inhibitive properties for use on metals.
production lot - that part of one manufacturerÕs production made from the same nominal raw material under essentially the same conditions and designed to meet the same specifications.
profile - the topographic contour of the exposed surface of a material or substrate.
profilometer - equipment used to measure profile of traveled surface roughness.
promoter - substance that activates catalysts and promotes polymerization.
proportioning - selection of proportions of ingredients to make the most economical use of available materials to produce cementitious repair materials with the required properties. (See also mixture.)
proprietary - made and marketed by one having the exclusive right to manufacture and distribute.
protection - the process of maintaining a concrete structure in its present or restored condition by minimizing the potential for deterioration or damage in the future. (See also maintenance and preservation.)
pullout test - a test that measures the force required to extract an embedded insert from a concrete mass; the measured ultimate pullout load is used to estimate the in-place compressive strength of the concrete.
pulse-echo method - a nondestructive testing method based on stress wave propagation; the presence and position of a reflector, such as a crack or void, are indicated by the echo amplitude and time.
pulse velocity - the velocity at which compressional or other waves are propagated through a medium.
pultrusion - a manufacturing process for resin-impregnated reinforcements such as rods, tubes, sheets, and shapes of uniform cross section, in which the reinforcement, after being wet-out by the resinapplication system, is drawn through a die to form the desired cross section; the reverse of the extrusion manufacturing process.
pumpability - a measure of the properties of a particular grout mix to be pumped as controlled by the equipment being used, the formation being injected, and the engineering objective limitations.
pumped concrete - see concrete, pumped.
pumping test - a field procedure used to determine in situ permeability or the ability of a formation to accept grout.
quality assurance - steps taken by or for the owner to assure the quality of the work.
quality control - steps taken by the contractor to control quality of the work.
radar - a nondestructive testing method for locating metal embedments, voids beneath pavements, or determining thickness of members; interface between materials with different dielectric properties results in reflection of a portion of incident electromagnetic pulse.
radiography - a nondestructive testing method for locating reinforcing and prestressing steel, conduits, pipes, voids, and honeycomb; the intensity of high-energy electromagnetic radiation which passes through a member is recorded on photographic film.
ramming - using a heavy blunt tool to tamp concrete. (See also dry pack, and tamping.)
rapid chloride test - a method for on-site determinations of d-soluble and water-soluble chloride ion contents of concrete powder samples with proprietary chloride extraction liquids and calibratedinstrument probes.
rapid-setting cement - see cement, rapid setting.
reactant - a material that reacts chemically with the base component of a grout system.
reactive aggregate - see aggregate, reactive.
rebound - aggregate and cement, or wet shotcrete, that bounces away from the surface against which shotcrete is being projected.
rebound hammer - a nondestructive testing apparatus that provides a rapid indication of the near-surface mechanical properties of hardened cementitious materials based on the distance of rebound of a springdriven plunger.
reflection cracking - the occurrence of cracks in overlays and toppings that coincide with the location of previously existing cracks in the substrate.
refusal - when the rate of grout take is low, or zero, at a given pressure.
rehabilitation - the process of repairing or modifying a structure to a desired useful condition. (See also repair, and restoration.)
reinforcement - (1) bars, wires, strands, fibers, or other slender members which are embedded inconcrete primarily to improve tensile strength; (2) fibers and fillers that improve the physical strength of coating systems.
reinforcement continuity - a condition in reinforced concrete in which the reinforcing steel is sufficiently interconnected to provide a path for electrical current.
relative humidity - the ratio of the quantity of water vapor in the air to the maximum amount the air would hold at the same temperature, expressed as a percentage.
release agent - material used to prevent bonding of concrete to a surface. (See also bond breaker.)
render - to apply a coat of mortar by a trowel or float.
repair - to replace or correct deteriorated, damaged, or faulty materials, components, or elements of a structure. (See also rehabilitation, and restoration.)
repair systems - the materials and techniques used for repair.
resin - a natural or synthetic, solid or semisolid, organic material of indefinite and often high molecular weight having a tendency to flow under stress; usually has a softening or melting range, and usually fractures conchoidally.
resin concrete - see concrete, polymer.
restoration - the process of re-establishing the materials, form, and appearance of a structure to those of a particular era of the structure. (See also rehabilitation, and repair.)
restraint - internal or external restriction of free movement of fresh or hardened concrete, mortar, or grout.
retarder - an admixture that delays the setting of cement paste, and hence of mixtures such as grout, mortar, or concrete containing cement.
retempering - addition of water and remixing of concrete or mortar that has lost enough workability to become unplaceable or unusable. (See also tempering.)
rheology - the flow characteristics of a material, including viscosity.
rock pocket - a porous, mortar-deficient portion of hardened concrete consisting primarily of coarse aggregate and open voids; caused by leakage of mortar from the form, separation (segregation) during placement, or insufficient consolidation. (See also honeycomb.)
rod - sharp-edged cutting screed used to trim shotcrete to forms or ground wires. (See also screed.)
rodding - consolidating concrete with a tamping rod. (See also rod, and tamping.)
roller-compacted concrete - see concrete, roller-compacted.
roller compaction - use of a vibratory, or other type roller, to compact concrete.
rolling - an uneven, wavy, textured surface at the outer edge of a spray pattern resulting from theapplication of shotcrete at angles less than 90 deg to the receiving surface.
rotary drilling - a process for drilling a hole with a rotating drill bit under constant pressure. (See also percussion drilling.)
rout - to deepen and widen a crack to prepare it for patching or sealing.
roving - a collection of bundles of continuous glass fiber filaments, either as untwisted strands or as twisted yarns.
runs - sagging and curtaining of a coating usually caused by improper mixing or poor applicationtechniques.
rust - a corrosion product consisting primarily of hydrated iron oxide.
rustication - a strip of wood or other material attached to a form surface to produce a groove in the repair.
rutting - the formation of depressions in a concrete surface caused by the excessive loading and abrasive wearing action of traffic.
sacrificial anodes - chemically active metals such as zinc, aluminum, and magnesium which, whenelectrically connected to the reinforcing bar, will provide the energy needed to cathodically protect the reinforcing bar; sacrificial anodes deteriorate in service at a rate proportional to the energy neede to protect the reinforcing bar plus whatever may deteriorate by local-action corrosion.
sagging - nonuniform downward flow of a material that occurs between the time of application and setting. (See also sloughing).
sample - a portion of material taken from a larger quantity of material which serves to provide information that can be used as a basis for action on the larger quantity.
sandblasting - a method of cutting or abrading a surface with a stream of sand ejected from a nozzle at high speed by compressed air. (See also abrasive blasting.)
sand pocket - a zone in concrete, mortar, or shotcrete containing fine aggregate with little or no cement.
sand streak - a streak of exposed fine aggregate in the surface formed concrete, caused by bleeding.
sanded grout - a grout mixture that contains fine aggregates.
saponification - alkaline hydrolysis of esters to produce the component soaps and alcohols.
saturated surface-dry - condition of an aggregate particle or other porous solid when the permeable voids are filled with water and no water is on the exposed surfaces.
saturation, critical - see critical saturation.
saw cut - a cut in hardened concrete made by abrasive blades, discs, or diamond wires.
scabbler - equipment for removal of concrete and coatings by chipping with piston-driven cutting heads placed at a right angle to the surface.
scaling - local flaking or peeling away of the near-surface portion of hardened concrete or mortar. (See also peeling, and spalling.) Note: light scaling of concrete does not expose coarse aggregate; medium scaling involves loss of surface mortar to 5 to 10 mm in depth and exposure of coarse aggregate; severe scaling involves loss of surface mortar to 5 to 10 mm in depth with some loss of mortar surrounding aggregate particles 10 to 20 mm in depth; very severe scaling involves loss of coarse aggregate particles as well as mortar generally to a depth greater than 20 mm.
scarifier - milling equipment for removal of concrete or brittle coatings by fracturing and pulverizing with rotary impact cutters held at a right angle to the surface.
scarification - the process of scratching, cutting, or chipping a substrate to clean and texture the surface.
Schmidt hammer - see rebound hammer.
scour - erosion of a concrete surface, exposing the aggregate.
screed - (1) to strike off concrete lying above the desired plane or shape. (2) a tool for striking off the concrete surface, sometimes referred to as a strikeoff.
screed wire - see ground wire.
screeding - the operation of forming a surface by the use of screed guides and a strikeoff. (See also
seal - a barrier against the passage of liquids, solids, or gases.
sealant - a material that has adhesive and cohesive properties to form a seal.
sealing compound - a liquid that is applied as a coating to the surface of hardened concrete to minimize ingress of liquid or gaseous media during service exposure.
seepage - the infiltration or percolation of water through a material to or from the surface.
segregation - the differential concentration of the components of mixed concrete, aggregate, or the like, resulting in nonuniform proportions in the mass. (See also bleeding and separation.)
self-leveling - the process whereby a material exhibits flow sufficient to seek gravitational leveling.
series grouting - similar to stage grouting, except each successively deeper zone is grouted by means of a newly drilled hole, eliminating the need for washing grout out before drilling the hole deeper.
service life - an estimate of the remaining useful life of a structure based on the current rate of deterioration or distress, assuming continued exposure to given service conditions without repairs.
set - the condition reached by a cement paste, mortar, or concrete when it has lost plasticity to an arbitrary degree, usually measured in terms of resistance to penetration or deformation.
settlement - (1) downward movement of a structure, part of a structure, or underpinning. (2) sinking of solid particles in grout, mortar, or fresh concrete, after placement and before initial set.
settlement shrinkage - a reduction in volume of concrete prior to the final set of cementitious mixtures, caused by settling of the solids. (See also shrinkage, plastic, and volume change, autogenous.)
shear - an internal force tangential to the plane on which it acts.
shear-bond strength - a measure of the ability of a repair to resist shear stresses along the interface between the repair material and the concrete substrate.
shear stress - the stress component acting tangentially to a plane.
sheath - an enclosure in which post-tensioning tendons are encased to prevent bonding during concrete placement. (See also duct.)
shelf life - the length of time packaged materials can be stored under specified conditions and still remain usable.
shooting - placing of shotcrete. (See also gunning.)
short-pulse radar - a technique for nondestructive detection of delaminations and other types of defects within a concrete mass.
shotblasting - surface preparation method in which steel shot is centrifugally propelled at high velocity onto a surface; the process is confined in an enclosed blast chamber which recovers and separates dust and reusable shot.
shotcrete - mortar or concrete pneumatically projected at high velocity onto a surface; also known as air-blown mortar, pneumatically applied mortar or concrete, and sprayed concrete. (See also drymix
shotcrete, pneumatic feed, positive displacement and wet-mix shotcrete.)
shotcrete, dry-mix - see dry-mix shotcrete.
shotcrete, wet-mix - see wet-mix shotcrete.
shrinkage - a decrease in one or more dimensions of an object or material. (See also contraction,volume change.)
shrinkage, carbonation - shrinkage caused by carbonation.
shrinkage, drying - see drying shrinkage.
shrinkage, plastic - see plastic shrinkage.
shrinkage-compensating - a characteristic of grout, mortar, or concrete made using an expansive cement in which volume increases after setting, if properly elastically restrained, induces compressive stresses which are intended to approximately offset the tendency of drying shrinkage to induce tensile stresses. (See also cement, expansive.)
shrinkage crack - a crack caused by restrained shrinkage.
shrinkage cracking - cracking that occurs in a repair when the restrained contraction induced bymoisture loss or carbonation exceeds the tensile strain capacity of the material.
shrinkage-reducing admixture - chemical admixture that reduces drying shrinkage by reducing capillary tension of pore water.
silane - a low-molecular-weight compound of silicon and hydrogen, solutions of which are used aspenetrating sealers for concrete surfaces.
silica fume - very fine noncrystalline silica produced in electric arc furnaces as a byproduct of the production of elemental silicon or alloys containing silicon; also known as condensed silica fume and microsilica.
silicone - water-repellent resin that may be used in coatings and caulking compounds and as admixtures for concrete.
siloxane - a silicon and oxygen-based compound, also containing carbon and hydrogen, used as a penetrating sealer for concrete surfaces.
skinning - the formation of a solid membrane on the top of a liquid, caused by partial curing or drying of a coating during storage.
slabjacking - the process of either raising concrete slabs or filling voids under them, or both, by pressure injecting cementitious or noncementitious materials under the slabs.
slant-shear bond strength - adhesive bond strength measured by applying a compressive force to a cylinder or prism that is comprised of two segments joined along a surface diagonal to the direction of the compressive force.
sloughing - subsidence of shotcrete, or other repair materials placed vertically or overhead, also called sagging.
slugging - pulsating and intermittent flow of shotcrete material due to improper use of delivery equipment and materials.
slurry - a mixture of water and any finely divided insoluble material, such as portland cement, slag, or clay in suspension.
slush grouting - application of cement slurry to surface rock as a means of filing cracks and surface irregularities or to prevent slaking; also applied to riprap to form grouted riprap.
sodium chloride - common salt.
soffit - the underside of an element or structure, such as a beam, staircase, arch, or cornice.
solids content - the percentage by weight of the nonvolatile matter in an adhesive.
soluble chloride - the fraction of the total chloride-ion content within hardened concrete that is available to act as an electrolyte in the electrochemical process of reinforcing steel corrosion.
solution cavern - holes left in rock masses when moving water carries away soluble materials.
solvent - a liquid capable of dissolving another material.
solvent entrapment - the encapsulation of solvent within a cured coating because of improper drying conditions; results in a discontinuous coating system.
sonic echo - a nondestructive testing method for determining the length of deep foundations or thelocation of cracks or constrictions; a hammer is used to impact the surface and a receiver monitors reflected stress wave.
sounding - a technique to evaluate the condition of hardened concrete by striking the surface with a hammer; sound concrete will exhibit a clear ringing sound, whereas dull or hollow sounds indicate delaminated areas. (See also chain drag.)
sounding well - a vertical pipe, with closely spaced openings, positioned in a mass of coarse aggregate for grout injection of preplaced aggregate concrete, a float on a measured line indicates the grout level.
spall - a fragment, usually in the shape of a flake, detached from a larger mass by a blow, by the action of weather, by pressure, or by expansion within the larger mass; a small spall involves a roughly circular depression not greater than 120 mm in depth and 150 mm in any dimension; a large spall, may be roughly circular or oval or in some cases elongated, is more than 20 mm in depth and 150 mm in greatest dimension.
spalling - the development of spalls.
specific gravity - the ratio of the mass of a volume of a material at a stated temperature to the mass of the same volume of distilled water at a stated temperature.
spectral analysis of surface waves (SASW) - a nondestructive test method for determining the stiffness profile of a pavement system or the depth of deteriorated concrete; impact is used to generate a surface wave and two receivers monitor the surface motion.
splitting tensile strength - tensile strength of concrete determined by a diametrical compression test.
sprayed concrete - see shotcrete.
spray-up application - technique in which continuous-strand roving is fed into a chopper gun, which chops the roving into predetermined lengths and simultaneously sprays the chopped fibers and a cementing matrix onto a surface.
stage grouting - sequential grouting of a hole in separate steps or stages in lieu of grouting the entire length at once; holes may be grouted in ascending stages by using packers or in descending stages downward from the collar of the hole.
stain - discoloration caused by a penetrating substance.
stalactite - a downward-pointing deposit formed as an accretion of mineral matter produced byevaporation of dripping water from the surface of rock or of concrete, commonly shaped like an icicle.
stalagmite - an upward-pointing deposit formed as an accretion of mineral matter produced byevaporation of dripping water from the surface of rock or of concrete, commonly conical in shape.
standard - (1) a physical reference used as a basis for comparison or calibration; (2) a concept that has been established by authority, custom, or agreement to serve as a model or rule in the measurement of quality or the establishment of a practice or procedure.
stitch drilling - procedure for removal of concrete with overlapping bore holes along the perimeter of the section to be cut out.
stitching - a method for repair of cracks that involves drilling holes on both sides of the crack andgrouting in stitching dogs (U-shaped metal units with short legs) that span the crack; may be used when tensile strength must be reestablished across major cracks.
straightedge - a straight wooden or metal strip used to level a concrete surface to proper grade or verify the planeness of a finished grade. (See also rod, screed, and strikeoff.)
strain - the change in length per unit of length, in a linear dimension of a body.
stratification - a layered structure in concrete resulting from placement of successive batches that differ in appearance.
strengthening - the process of restoring the capty of weakened components or elements to their original design capty or of increasing the strength of components or elements of a concrete structure. See also external strengthening.)
stress - intensity of internal force (i.e., force per unit area) exerted by either of two adjacent parts of a body on the other across an imagined plane of separation.
stress corrosion - the process in which the damage caused by stress and corrosion acting together issignificantly greater than that produced when they act individually.
stress-corrosion cracking - a cracking process that requires the simultaneous action of a corrodent and sustained tensile stress.
stress relaxation - the time-dependent decrease in stress in a material held at constant strain. (See also creep.)
strikeoff - to remove repair material in excess of that which is required to fill the repair cavity evenly or bring the surface to grade; performed with a straightedge piece of wood or metal by means of a forward sawing movement or by a power operated tool appropriate for this purpose; also the name applied to the tool. (See also screed and screeding.)
structural adhesive - a bonding agent used for transferring required loads between adjacent structural elements.
structural sealant - a sealant capable of transferring required loads between adjacent structural elements.
styrene butadiene - a synthetic resin which is a copolymer of styrene and butadiene; available as a latex emulsion and in a form which can be dissolved in aromatic solvents to form alkali-resistant coatings.
substrate - the layer immediately under a layer of different material to which it is typically bonded; an existing concrete surface that receives an overlay, partial-depth repair, protective coating, or some other maintenance or repair procedure.
sulfate attack - deterioration of concrete or mortar caused when the cement-paste matrix reacts chemically or physically with sulfates in soil or ground water.
superplasticizer - see admixture, water-reducing (high range).
supplemental reinforcement - additional reinforcement installed in a repair section when the original reinforcement was inadequate, the reinforcement has lost cross section, or the existing member is to be strengthened.
surface hardeners - metallic particles or hard mineral aggregate usually passing No. 16 sieve size, mixed with cement; generally applied by sprinkling on the surface of plastic concrete, or other repair material, and repeated troweling to produce a dense layer.
surface impregnants - low viscosity, surface penetrating liquids which impart a degree of water repellency to the surface.
surface preparation - the process whereby a method or combination of methods is used to removedeteriorated or contaminated concrete and roughen and clean a substrate to enhance bond of a repair material or protective coating.
surface repair - repair of a concrete surface, e.g., application of an overlay, or repair of near-surface concrete that constitutes only a small portion of the depth of a member or element. (See also partialdepth repair.)
Surface retarder - a retarder applied to the contact surface of a form or to the surface of newly placed concrete, to delay setting of the cement, to facilitate construction joint cleanup, or to facilitate production of exposed-aggregate finish.
surface sealers - (1) in epoxy injection, the material placed over cracks to contain the liquid adhesive during the injection process before the adhesive gels. (2) protective surface treatments 10 mils (0.25 mm)or less in thickness which are generally applied with brush, roller, squeegee, or spray.
surface tension - a measure of surface energy created by the predisposition of molecular forces at the surface of a liquid to confine the volume of the liquid to a minimum area.
surface texture - degree of roughness or irregularity of the exposed surfaces.
surface vibrator - a vibrator applied to the surface of freshly placed repair materials to consolidate the mass; four principal types exist: vibrating screeds, pan vibrators, plate or grid vibratory tampers, and vibratory roller screeds.
suspension - a relatively coarse, noncolloidal dispersion of solid particles in a liquid.
swelling - increase in either length or volume. (See also contraction; expansion; volume change; and volume change, autogenous.)
syneresis - the exudation of small amounts of liquid from a gel accompanied by contraction of the gel.
synthetic fibers - polymeric fibers, such as polypropylene, polyolefin, nylon, polyethylene, polyester, and acrylic, that can be used in fiber-reinforced cementitious materials and protective coating systems.
tacky - the sticky condition of an adhesive prior to hardening.
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 finishing. (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.)
temperature cracking - cracking which occurs when strains, induced by restrained contraction because of decreases in temperature, exceed the tensile strain capacity of a material.
temperature rise - the increase of temperature caused by either absorption of heat or internal generation of heat, e.g., hydration of cement in concrete.
tempering - the addition of water and mixing of concrete or mortar as necessary to bring the mixture initially to the desired consistency. (See also retempering.)
tendon - a steel element such as wire, cable, bar, rod, or strand, or a bundle of such elements, typically used in tension to impart compressive stress to concrete and as external strengthening to increase structural capacity.
tensile bond strength - the unit stress, applied in direct tension, required to separate a hardened repair material from other materials with which it is in contact with failure occurring in or near the bonded interface.
tensile strength - maximum unit stress that a material is capable of resisting under axial tensile loading; based on the cross-sectional area of the specimen before loading.
tensile stress - see stress.
test - a chemical or physical evaluation of a material, structural element, or structure by experiment, observation, or inspection.
thermal conductivity - the property (of a homogeneous body) measured by the ratio of the steady-state heat flux (time-rate of heat flow per unit area) to the temperature.
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.
thermal expansion - expansion caused by increase in temperature.
thermal shock - the subjection of a material or body to a rapid change in temperature which 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.
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.
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.
time-dependent deformation - see deformation, time-dependent.
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. (See also keyway.)
tolerance - the permissible deviation from a specified dimension, quantity, location or alignment.
tooling - the act of compacting and contouring a material in a joint.
topping - a layer of concrete, mortar, or other material placed to form a floor or surface on a concrete base.
toughness - the capacity of material to absorb energy.
toxic - poisonous.
transverse crack - crack generally perpendicular to the length of a member.
tremie - a pipe or tube through which concrete is deposited under water.
tremie concrete - see concrete, tremie.
tremie seal - the depth to which the discharge end of the tremie pipe is kept embedded in the freshconcrete 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.
trowel - a flat, broad-bladed steel hand tool used in the final stages of finishing operations to impart a relatively smooth surface to concrete and other repair materials.
trowel finish - the smooth or textured finished of an unformed surface obtained by troweling.
troweling - smoothing and compacting the unformed surface of materials by strokes of a trowel; method for application of mortars and grouts in shallow or limited areas of repair where reinforcing steel is not exposed.
true solution - one in which the components are 100 percent dissolved in the base solvent.
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.
ultrasonic echo - a nondestructive testing method for locating delaminations and voids in relatively thin elements with a transducer that emits a short pulse of ultrasonic waves which is reflected by the opposite side of an element or internal defect and recorded by an adjacent receiver.
ultrasonic pulse velocity - a nondestructive testing method for assessing the relative condition of hardened concrete by measuring the travel time of a pulse of ultrasonic waves through a section with a known path length.
unwatering - the interception, removal, or control of ponded or flowing surface water within structures or excavations. (See also dewatering.)
uplift - vertical displacement of a structure or formation because of grout injection.
urea - white crystals or powder, soluble in water and used as a deicer.
urea resin - a synthetic resin made from urea and an aldehyde.
urethane - a class of resins obtained by the reaction of diisocyanates with organic compounds containing two or more active hydrogen atoms to form polymers having free isocyanate groups. Under the influence of heat or catalysts, the latter react with each other, with water, glycols, diamines, etc., to form a thermosetting material.
vacuum blasting - a closed-loop abrasive blasting process whereby blasting material and associated debris are contained with a vacuum.
vacuum concrete - see concrete, vacuum.
vacuum impregnation - a repair process in which a vacuum applied to a concrete section causes polymers such as epoxy to impregnate the concrete surface or fill cracks and voids within the section.
vapor barrier - a moisture impervious layer which retards transmission of water vapor into a material or structure.
vehicle - the liquid portion of coating in which pigment is dispersed; composed of binder and thinner.
vent - a hole or small-diameter pipe that permits the escape of air and water during material placement; also used to monitor the flow of grout.
vibration - consolidation of freshly-mixed materials following placement by mechanical devices oscillating at moderately high frequency.
vibrator - an oscillating machine used to agitate freshly-mixed materials such as concrete or mortar to produce a uniform material without gross voids, and to produce intimate contact with the substrate, boundary of repair cavity, form surfaces, and embedded materials.
vinyl ester resin - a thermosetting material produced by a reaction between epoxy resin and methacrylic, or other polymerizable unsaturated d, that is then diluted with a reactive monomer, usually styrene.
viscometer - instrument used for measuring viscosity of slurries, mortars, or concretes.
viscosity - the property of a material that resists change in the shape or arrangement of its elementsduring flow, and the measure thereof.
visual inspection - an evaluation procedure in which a qualified investigator observes, classifies, and documents deterioration or distress on exposed concrete surfaces; typically, one of the first steps in evaluation of a concrete structure.
void - cavity enclosed within an otherwise solid mass; may be intentionally or unintentionally formed and may be filled with air, water, or other gaseous or liquid material.
void ratio - the ratio of the volume of void space to the volume of solids.
volatile content - the percentage of materials which evaporate from a coating.
volatile organic compounds (VOC) - a measure of the total amount of organic compounds evaporating from a coating film, excluding water.
volume change - an increase or decrease in volume of a material. (See also deformation and
volume change, autogenous - change in volume produced by continued hydration of cement, exclusive of effects of applied load and change in either thermal condition or moisture content.
warping - a deviation of a surface from its original shape, usually caused by either temperature ormoisture differentials, or both, within the material. (See also curling.)
washout - erosion of the surface layers of a freshly-mixed material by the flow of water over its surface, e.g.,the washout of cement from concrete or mortar.
water absorption - the amount of water a material absorbs under specified test conditions.
water-activated grout - a class of injection grouts that react with water to form polyurethane polymers.
water beading - surface property that causes the formation of discrete water droplets on a surface.
water blast - water discharged through a nozzle at high velocity; used to cut or abrade a concrete surface.
water-cement ratio - the ratio of the amount of water, exclusive only of that absorbed by the aggregates, to the amount of cement in a concrete, mortar, grout, or cement paste mixture; preferably stated as a decimal by mass and abbreviated w/c.
water-cementitious material ratio - the ratio of the amount of water, exclusive only of that absorbed by the aggregate, to the amount of cementitious material in a concrete or mortar mixture.
waterproof - impervious to water in either liquid or vapor state. (Since nothing can be completelyimpervious to water under infinite pressure over infinite time, this term should not be used.)
water-reducer - an admixture that allows for a decrease in the amount of water used in freshly mixed mortar or concrete without a decrease in slump or that will increase slump if water content is unchanged.
water ring - a device in the nozzle body of dry-mix shotcrete equipment through which water is added to the materials.
waterstop - a thin sheet of metal, rubber, plastic, or other material installed across a joint to impede seepage.
watertight - impermeable to water except when under hydrostatic pressure sufficient to produce structural discontinuity by rupture.
water vapor permeability - the time rate of water vapor transmission through unit area of flat material of unit thickness induced by vapor pressure difference between two specific surfaces, under specified temperature and humidity conditions.
water vapor permeance - the time rate of water vapor transmission through unit area of flat material or construction induced by vapor pressure difference between two specific surfaces, under specified temperature and humidity conditions.
water vapor transmission - the rate of water vapor flow through a unit area of a material, normal to specific parallel surfaces, under specific conditions of temperature and humidity at each surface. (See also permeability, permeance, and perm.)
water vapor transmission rate - the steady water vapor flow in unit time through unit area of a body, normal to specific parallel surfaces, under specific conditions of temperature and humidity at each surface.
wearing course - an abrasion-resistant surface treatment applied to concrete pavement or concrete slabs.
weathering - degradation in color, texture, strength, chemical composition or other properties of a material caused by exposure to the weather.
wet blasting - a process for cleaning or finishing a surface by directing a water-based abrasive slurry at high velocity against the surface.
wet-mix shotcrete - shotcrete in which all components are mixed before the material is pumped into the delivery hose; an accelerator, if used, may be added at the nozzle.
wettest stable consistency - the condition of maximum water content at which cement grout and mortar will adhere to a vertical surface without sloughing.
wetting agent - a substance used to reduce the surface tension of liquids so that solid surfaces can be wetted and liquids can penetrate the capillaries.
Windsor probe - a device developed to estimate the quality and compressive strength of insitu concrete by measuring the depth of penetration of probes driven into the concrete surface by means of a powderactuated driver.
workability - that property of freshly-mixed materials which determines the ease and homogeneity with which it can be mixed, placed, consolidated, and finished.
working life - the period of time during which an adhesive, after mixing with catalyst, solvent, or other compounding ingredients, remains sufficiently workable to permit application and spreading.
X-ray diffraction - the diffraction of X-rays by substances having a regular arrangement of atoms; a phenomenon used to identify substances having such a structure.
X-ray fluorescence - characteristic secondary radiation emitted by an element as a result of excitation by X-rays, used to yield chemical analysis of a sample.
X-ray radiograph - an X-ray film, plate, or paper that is placed at the image plane and is used for
recording an X-ray image of the object being examined.
yellowing - discoloration of white or clear coatings caused by of aging.
yield - the volume of a freshly mixed material produced from a known quantity of ingredients; the total weight of ingredients divided by the unit weight of the freshly mixed material.
yield point - that point on the stress-strain curve when stress ceases to be linearly proportional to strain.
Young's modulus - see modulus of elasticity.
Zahn cup - an apparatus for the measurement of liquid or slurry viscosity expressed as the number of seconds required for the liquid or slurry to drain from the cup through a hole of definite diameter.
zinc-rich primer - a primer that contains a high enough concentration of zinc dust to make it electrically conductive when it dries so that it provides cathodic protection for ferrous materials.