Concrete Repair Terminology is prepared by the International Concrete Repair Institute. The cross-referenced terms provide definitions for commonly used words in concrete repair, restoration and protection.
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Revised April 2019
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containing calcium carbonate or, less generally, containing the element calcium.
a white, deliquescent, hygroscopic compound, CaCl2; can be used, in various technical grades, as a drying agent, an accelerator, a deicing chemical, a refrigerant, and to prevent dust.
an electrode widely used as a reference electrode of known potential in electrometric measurement of acidity and alkalinity, corrosion studies, voltammetry, and measurement of the potentials of other electrodes.
the movement of a liquid in the interstices of concrete, soil, or other finely porous material due to surface tension.
flow of moisture through a capillary pore system, such as in concrete.
the conversion of calcium ions in hardened cementitious materials to calcium carbonate by reaction with atmospheric carbon dioxide in the presence of water (sufficient humidity); carbonation reduces the pH of the concrete and its ability to protect reinforcing steel and embedded metal items from corrosion.
frequently used repair technique in which mortar, concrete, or other materials are deposited in workable condition in the place where they harden and become part of the structure.
a substance that significantly increases the rate of curing of a binder when added in a small quantity relative to the amount of primary reactants.
those materials that, in combination, cause chemical reactions to begin; catalyst systems normally consist of an initiator (catalyst) and an activator.
the electrode at which electrons are consumed and chemical reduction occurs; the area where electrons are flowing into the reinforcing steel.
a chemical substance that prevents or reduces the rate of the cathodic or reduction reaction.
a form of corrosion protection for steel in reinforced concrete wherein sufficient current is distributed to the reinforcement, thereby protecting the reinforcement from corrosion.
cathodic protection, impressed current
a protection system that uses an external power supply to force a small amount of electric current through the reinforcing steel to counteract the flow of current caused by the corrosion process; a metal, such as platinum, niobium, coated titanium or a titanium sub-oxide that corrodes at a very slow rate, is typically provided as an anode.
cathodic protection, sacrificial
protection system that does not require an external power supply; a metal, such as zinc that is less noble or more prone to corrosion than steel, corrodes in place of the reinforcing steel thus protecting the structure.
electrode reaction equivalent to a transfer of negative charge from the electronic to the ionic conductor; a cathodic reaction is a reduction process.
a positively charged ion.
to install or apply a sealant across or into joints, cracks, or crevices to prevent the passage of air or water.
pitting of concrete caused by implosion of water vapor bubbles in fast- flowing water; bubbles form in areas of subatmospheric pressures immediately downstream from an obstruction or offset and collapse as they enter areas of higher pressure.
any of a number of materials that are capable of binding aggregate particles together. (See also cement, hydraulic.)
a hydraulic cement essentially consisting of portland cement, slag cement, or both, uniformly mixed with each other or a pozzolan through intergrinding or blending
the product obtained by pulverizing clinker consisting essentially of hydraulic calcium aluminates resulting from fusing or sintering a suitably proportioned mixture of aluminous and calcareous materials; called high-alumina cement in the United Kingdom.
a type of cement that produces a paste that, after setting, increases in volume to a significantly greater degree than does portland-cement paste; used in some repair materials to compensate for drying shrinkage.
Portland cement characterized by attaining a given level of strength in mortar or concrete earlier than does normal Portland cement; referred to in the United States as Type III.
a binding material that sets and hardens by chemical reaction with water and is capable of doing so underwater. For example, Portland cement and slag cement are hydraulic cements.
cement, magnesium phosphate
a blend of magnesium oxide and ammonium dihydrogen phosphate that reacts with water, rapidly producing strength and heat; rapid- setting cement that can be used at low temperatures.
normally a proprietary blend of finely ground blast furnace slag and Portland cement.
cement, ordinary Portland
the term used in the United Kingdom and elsewhere to designate the equivalent of American normal Portland cement or Type I cement; commonly abbreviated OPC.
a hydraulic cement produced by pulverizing Portland-cement clinker and usually containing calcium sulfate.
a hydraulic cement containing fluorine-substituted calcium aluminate, capable of very rapid setting.
granulated blast-furnace slag that has been finely ground and that is hydraulic cement.
Portland cement with a low tricalcium aluminate content, which makes concrete more resistant to damage from dissolved sulfates in water or soils.
Portland cement which hydrates to a white paste, made from raw materials of low iron content.
binder of concrete and mortar consisting essentially of cement, water, hydration products, and any admixtures together with very finely divided materials included in the aggregates. (See also cement paste, neat.)
a mixture of hydraulic cement and water.
pressure injection of cement grout into gravel, fractured rock, etc., to solidify it.
properly, material having cementitious properties, practically considered to be that fraction of an inorganic material (mortar or concrete) passing a 90 m (micron) (No. 170 mesh) per ASTM E1..
a nondestructive testing method in which the sounds from chains dragged over a concrete surface are used to detect delaminations; dull or hollow sounds indicate delaminated areas, whereas non-delaminated concrete exhibits a clear ringing sound. (See also sounding or, more broadly, acoustic impact.)
the loose powder caused by decomposition of a concrete surface or degradation of a coating.
placing materials into a mixer or other container for further processing.
the process of forming complex chemical compounds in which certain metal ions are bound into stable ring structures, keeping the ions in solution and eliminating or reducing normal (and often undesirable) effects of the ions; similar to the process of sequestration.
material degradation by reaction with, dissolution by, or reduction of physical continuity from contact with a chemical agent or agents.
bond between materials that is the result of cohesion and adhesion developed by chemical reaction.
any mixture of materials used for grouting purposes in which all elements of the system are true solutions (no particles in suspension).
the ability of a material to resist degradation by reaction with, dissolution by, or reduction of physical continuity from contact with a chemical agent or agents, thereby retaining its capacity to perform as a structural or aesthetic element.
to remove all or part of a hardened concrete section with a chisel.
point with two major planes forming a “V” and a pair of minor planes on each flank; forming a hexagonal cross section.
contamination of concrete with chloride ions commonly used in deicing salts and accelerating admixtures such as calcium chloride and sodium chloride; chloride contamination above the threshold for corrosion can result in corrosion of the reinforcing steel.
total amount of chloride ion present in concrete or mortar.
the movement of chlorides over time within a concrete section due to concentration gradients.
anion of common deicing salts (sodium chloride) and of the accelerating admixtures calcium chloride.
the amount of chloride required to initiate steel corrosion in reinforced concrete under a given set of exposure conditions; commonly expressed in percent of chloride ion by mass of cement.
chemicals containing chlorine, which when mixed with water release a chloride ion (Cl-); an example is sodium chloride (salt).
resin produced by the reaction of natural rubber with chlorine gas; coatings formulated from this resin have good resistance to acids, alkalis, and chemicals generally, but not to aromatic solvents, gasoline, etc.
roved fibers that are chopped into short lengths for use in mats, spray-up, or molding compounds.
treatment of existing concrete substrate to remove all surface material and contamination down to a condition of cleanness corresponding to that of a freshly broken surface of concrete.
achieving the desired reduction in grout take by splitting the hole spacing; if closure is being achieved, there will be a progressive decrease in grout take as primary, secondary, tertiary, and quaternary holes are grouted.
a material produced by the destructive distillation of coal; coal tar epoxies are coatings in which the binder is a combination of coal tar and epoxy resins.
1) liquid, with or without fillers or reinforcement, that is applied to a substrate by brushing, dipping, mopping, spraying, troweling, etc., to form a material that will bond to and preserve, protect, decorate, seal, or smooth the substrate; also used to provide a barrier to contain chemicals; 2) in unbonded post-tensioned concrete, a material used to lubricate steel tendons or protect against corrosion.
protective surface treatment with a dry thickness greater than 10 mils (0.25 mm) and less than 30 mils (0.75 mm) applied to the surface of concrete.
the ratio of the force required to move one surface over another, to the total force applied normal to those surfaces.
coefficient of permeability
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 68 °F [20 °C]).
coefficient of thermal expansion
change in linear dimension per unit length or change in volume per unit volume per degree of temperature change.
a temporary structure enclosing all or part on a construction area so that construction or repair can proceed in the dry.
the mutual attraction by which the molecules of a solid or liquid are held together..
special concreting and construction practices used to offset the limiting effects of cold conditions.
1) jackets which surround only a portion of a column or pier; typically used to provide increased support to the structural member at the top of the column or pier; 2) the surface opening of a borehole.
an electrically charged particle, generally smaller than 0.1 mm, dispersed in a second continuous medium.
subsurface movement of grout from an injection hole to another hole or opening.
1) a balance of physical, chemical, and electrochemical properties and dimensions between a repair material and the existing substrate; 2) the capacity of two or more materials to combine or remain together without undesirable aftereffects; 3) mutual tolerance.
any combination of materials that results in a chemically stable repair system.
a balance of dimensions, or volumetric stability, between a repair material and the existing substrate.
a balance of electrochemical properties of two materials in contact.
a balance of thermal properties between a repair material and the existing substrate.
the ability of two or more materials to be placed in contact or in sufficiently close proximity to interact with no detrimental results.
a product or system made from two or more constituent materials that remain distinct, but combine to form a material with properties not possessed by any of the individual constituents; e.g., a composite repair that includes a concrete substrate, adhesive bonding agent, and repair material.
a type of construction with different materials and structural elements that are sufficiently interconnected that the combined components respond to loads as a unit.
a mixture of a polymer with other ingredients such as fillers, stabilizers, catalysts, processing aids, lubricants, modifiers, pigments, or curing agents.
a seal that is attained by a compressive force on the sealing material.
amount of a constituent substance expressed in relationship to the whole.
a composite material that consists essentially of a binding medium within which are embedded particles or fragments of aggregate, usually a combination of fine aggregate and coarse aggregate; in Portland cement concrete, the binder is a mixture of Portland cement and water, with or without admixtures.
concrete containing dispersed, randomly oriented fibers.
unhardened concrete that can be consolidated by the intended method.
concrete that contains high-early-strength cement or admixtures which allow it to reach a specified strength earlier than normal concrete would.
concrete that has a specified compressive strength for design of 8000 psi (55 MPa) or greater.
any volume of concrete with dimensions large enough to require that measures be taken to cope with generation of heat from hydration of the cement and attendant volume change to minimize cracking.
any element made of plain or reinforced concrete that is not part of a structural system required to transfer gravity, lateral load, or both, along a load path to the ground.
concrete without reinforcement.
a composite material in which the fine and coarse aggregates are bound together in a dense matrix with a polymer binder; also known as resin concrete.
a mixture of water, hydraulic cement, aggregate, and a monomer or polymer; polymerized in place when a monomer is used.
concrete produced by placing coarse aggregate in a form and later injecting a portland cement-sand grout, usually with admixtures, to fill the voids.
concrete (mortar, grout), preshrunk
1) concrete that has been mixed for a short period in a stationary mixer before being transferred to a transit mixer; 2) grout, mortar, or concrete that has been mixed 1 to 3 hr before placing in order to reduce shrinkage during hardening.
structural concrete in which internal stresses have been introduced to reduce potential tensile stresses resulting from loads.
concrete which is transported through a hose or pipe by means of a pump.
concrete containing adequate reinforcement (prestressed or not prestressed) and designed on the assumption that the two materials act together in resisting forces.
concrete compacted by roller compaction; concrete that, in its unhardened state, will support a roller while being compacted.
plain or reinforced concrete in a member that is part of a structural system required to transfer gravity and/or lateral loads along a load path to the ground.
concrete placed underwater with a tremie pipe or hose.
concrete from which excess water and entrapped air are extracted by a vacuum process before hardening occurs.
concrete of stiff or extremely dry consistency showing no measurable slump after removal of the slump cone.
hand-held or machine mounted equipment commonly used for removal of concrete by repeated striking of the surface to spall and fracture the concrete. (See also scabbler.)
concrete breakers, boom-mounted
mechanically operated equipment for removal of concrete by repeated, high energy and low-frequency striking of the surface to spall and fracture the concrete.
concrete breakers, hand-held
equipment commonly used for removal of concrete by repeated, low-energy and high-frequency striking of the surface to spall and fracture the concrete.
concrete breakers, impact
equipment for removal of concrete by repeated striking of the surface to spall and fracture the concrete; may produce microcracking in the concrete substrate.
to equalize the moisture in a material with that of a specified atmosphere.
condition assessment (structural)
a general term used to describe the systematic collection of information about an existing structure and evaluation of the collected information to make informed decisions regarding the need for repair or rehabilitation of the examined structure.
quantitatively defining the physical condition of a structure, principally by visual inspection and nondestructive tests supplemented by sampling and laboratory testing.
1) material property relating heat flux (heat transferred per unit area per unit time) to a temperature difference; 2) property of a water or soil sample to transmit electric current (inverse of resistivity) under a set of standard conditions. Usually expressed as microhms conductance.
(See ACI 562 for code specific language.)
the process whereby the volume of freshly placed mortar or concrete is reduced to the minimum practical space, usually by vibration, rodding, tamping, or some combination of these actions; to mold mortar or concrete within a form or repair cavity and around embedded items and reinforcement and eliminate voids other than entrained air. (See also rodding and tamping.)
injection of a fluid grout, usually sand, Portland cement, and water, into a compressible soil mass in order to displace it and form a lenticular grout structure for support.
the extent to which the design of a repair and material properties facilitates ease of construction, achieving a quality repair at an economic cost.
a means of connecting reinforcing bars in which the bars are lapped and in direct contact. (See also lap splice.)
any extraneous material on or within a concrete substrate that can cause deterioration, inhibit bond, or adversely impact performance of any applied repair or protection system.
a condition in reinforced concrete in which the reinforcing steel is sufficiently interconnected to provide a path for electrical current..
a mixer into which the ingredients of the mixture are fed without stopping, and from which the mixed product is discharged in a continuous stream.
a set of documents designed to define all aspects of the construction process. These documents typically consist of contract forms, contract conditions, specifications, drawings, addenda, and contract changes.
contract document to be signed by Owner, Design Professional and Contractor which confirms mutual agreement by all parties of modification to any contract terms (most typically changes to project work scope, cost and/or schedule).
agreement between an Owner and a Contractor which stipulates either a defined specific scope of services/work to be performed for a fixed payment amount or an open-ended scope with an intended end result to be performed for a fixed payment amount.
contract, time and materials
type of contract frequently used for evaluation investigations, or projects with potential hidden conditions and undefined scopes.
agreement between an Owner and a Contractor for a defined set of work tasks where the total quantity of work is variable. The quantity of work for each category is estimated and work is paid for on a unit price basis such as $/ft2.
person or entity that is under contract to the owner for the implementation of repairs to the structure.
a drawing together that reduces the volume or length of a mass or object.
controlled low-strength material
a self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill.
the top layer or a covering on a wall or pier exposed to the weather, usually sloped to carry off water.
copper-copper sulfate half cell
a commonly used standard reference electrode used to measure the electrical potential between it and the reinforcing steel.
a cylindrical sample of hardened concrete or rock obtained by means of a core drill.
ratio of the length of core recovered to the length of hole drilled, usually expressed as a percentage.
the process of drilling and extracting cores from concrete structures or rock foundations.
destruction of metal by chemical, electrochemical, and electrolytic reaction within its environment.
area of concrete in which there is a flow of electrons from anode to cathode.
the amount of current flowing from an anode to a cathode in a corrosion cell, usually reported as µA; if normalized for the area over which the corrosion is occurring, it is reported in µA/cm2 for corrosion cells in concrete.
a chemical compound that, when used as an admixture in fresh concrete or as a topical application to hardened concrete, prevents or reduces corrosion of embedded metals.
corrosion inhibitor, surface applied
a chemical compound that, when used as a topical application to hardened concrete in the proper concentration and form, prevents or reduces corrosion.
the potential of a corroding surface in an electrolyte relative to a reference electrode measured under open-circuit conditions.
substance formed as a result of corrosion.
the amount of corroding material being lost, usually reported as mass change per unit area per unit time or penetration per unit time mils/year or µm/year; in steel, one µA/unit area is the equivalent to 11 µm/year/unit area.
ability of a metal to withstand corrosion in a given corrosion system.
the chloride ion concentration, in the vicinity of the reinforcing steel, sufficient to initiate active corrosion. There is conflicting data on threshold values; however, an acid-soluble chloride threshold value of 1.0 to 1.5 lb/yd3 of concrete is typically used in the United States.
the means for transmittal of prestressing force from one partial-length tendon to another.
1) in reinforced concrete, the least distance between the surface of the reinforcement and the outer surface of the concrete; 2) in grouting, the thickness of rock and soil material overlying the stage of the hole being grouted.
the area that a specified volume of coating will cover to a specified dry thickness.
a nondestructive testing instrument for locating embedded steel reinforcement, measuring depth of cover, and estimating the diameter of reinforcement by measuring the change in a low frequency alternating magnetic field applied on the surface of a member. Also known as a pachometer and rebar locator.
a complete or incomplete separation of concrete into two or more parts produced by breaking or fracturing.
any crack for which the mechanism causing the cracking is still at work; any crack that is still moving.
any crack not likely to become active in the future or whose movement is of such magnitude that a repair will not be affected.
concrete surface crack with a width similar to the diameter of human hair (about 0.10 mm [0.004 in.]). Such cracks are difficult to observe unless the concrete surface is wetted and allowed to dry.
crack that generally parallels the length of a member.
crack that is not the result of external forces and has no effect on structural resistance or integrity; usually the result of shrinkage (plastic, settlement and drying), thermal changes, or internal chemical reaction.
crack caused by restrained shrinkage.
crack that is caused by dead loads, applied forces or other external forces.
crack caused by internally or externally restrained thermal expansion or contraction.
crack generally perpendicular to the length of a member.
the ability of repair or protective surface treatment to remain continuous when installed on a cracked concrete surface.
a method for sealing or repairing cracks by injecting a polymer or other material.
a device that measures the movement of cracks.
a series of cracks in concrete near and roughly parallel to joints, edges, and structural cracks.
1) intersecting cracks that extend below the surface of hardened concrete; caused by shrinkage of the drying surface concrete that is restrained by concrete at greater depths where either little or no shrinkage occurs; vary in width from fine and barely visible to open and well-defined; or 2) the chief symptom of chemical reaction between alkalies in cement and mineral constituents in aggregate within hardened concrete; due to differential rate of volume change in different portions of the concrete; cracking is usually random and on a fairly large scale, and in severe instances the cracks may reach a width of 0.50 in. (12.7 mm); also known as pattern cracking. (See also cracks, checking; and crazing.)
cracking that occurs in the surface of a fresh cementitious material soon after it is placed and while it is still plastic.
the occurrence of cracks in overlays and toppings that coincide with the location of previously existing active cracks in the substrate.
cracking of a structure or member due to restrained shrinkage caused by a reduction in moisture content, carbonation, or both.
a cracking process that requires the simultaneous action of a corrodent and sustained tensile stress.
cracking which occurs when strains, induced by restrained contraction because of decreases in temperature, exceed the tensile strain capacity of a material.
surface cracking that forms a pattern similar to alligator hide.
shallow, closely spaced cracks that form an irregular pattern. (See alsocracks, craze; and crazing.)
fine random cracks or fissures in a surface..
time-dependent deformation resulting from a sustained load.
creep that occurs because of compressive load.
creep that occurs because of tensile load.
a nondestructive testing method for locating low-quality concrete with transducers positioned along the length of holes drilled into a deep foundation. (See also ultrasonic pulse velocity.)
the chemical bonding between linear polymer chains to form a three-dimensional network, generally by covalent bonding.
arrangement of previously disordered material segments of repeating patterns into geometric symmetry.
the process by which a compound attains its intended performance properties by means of evaporation, chemical reaction, heat, radiation, or combinations thereof.
the time interval between formation or placement of a material and the material’s reaching specified design properties; some materials require specified treatment during this interval.
the maintenance of a favorable temperature and moisture environment for repair and protection materials during some definite period following placing, casting, or finishing so that the desired properties may develop.
a process that involves either liquid sealing compound or nonliquid protective coating, both of which function as films to restrict evaporation of mixing water from cementitious repair materials.
continuous or frequent application of water through ponding, fogging, steam, or saturated cover materials, such as burlap or cotton mats, and the minimization of water loss by use of plastic sheets or other moisture-retaining materials applied over newly placed concrete to promote cement hydration.
the distortion of an originally essentially linear or planar member into a curved shape such as the warping of a slab due to creep or to differences in temperature or moisture content in the zones adjacent to its opposite faces. (See also warping.)
a building facade made of glass and metal.
sharp-edged tool used to trim shotcrete to finished outline. (See also rod.)
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