Copy of `ACPA - American Pavement Glossary`

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ACPA - American Pavement Glossary
Category: Architecture and Buildings > concrete terms
Date & country: 25/09/2008, US
Words: 597


AASHTO
American Association of State Highway and Transportation Officials

Absolute Specific Gravity
The ratio of the weight referred to a vacuum of a given volume of material at a stated temperature to the weight referred to a vacuum of an equal volume of gas-free distilled water at the same temperature.

Absolute Volume
The displacement volume of an ingredient of concrete or mortar; in the case of solids, the volume of the particles themselves, including their permeable or impermeable voids but excluding space between particles; in the case of fluids, the volume which they occupy.

Absorbed Moisture
The moisture held in a material and having physical properties not substantially different from those of ordinary water at the same temperature and pressure.

Absorbed Water
Water held on surfaces of a material by physical and chemical forces, and having physical properties substantially different from those of absorbed water or chemically combined water at the same temperature and pressure.

Absorption
The amount of water absorbed under specific conditions, usually expressed as a percentage of the dry weight of the material; the process by which the water is absorbed.

Acceleration
Increase in rate of hardening or strength development of concrete.

Accelerator
An admixture which, when added to concrete, mortar, or grout, increases the rate of hydration of hydraulic cement, shortens the time of set, or increases the rate of hardening or strength development.

AC
Asphalt Concrete; asphalt pavement

ACHM
Asphalt Concrete Hot Mix; asphalt pavement

ACI
American Concrete Institute

ACPA
American Concrete Pavement Association

ACR
Alkali-Carbonate Reaction

Adhesion Loss
The loss of bond between a joint sealant material and the concrete joint face noted by physical separation of the sealant from either or both joint faces.

Adhesives
The group of materials used to join or bond similar or dissimilar materials; for example, in concrete work, the epoxy resins.

Admixture
A material other than water, aggregates, and portland cement (including air-entraining portland cement, and portland blast furnace slag cement) that is used as an ingredient of concrete and is added to the bath before and during the mixing operation.

Adsorption
Development at the surface of a solid of a higher concentration of a substance than exists in the bulk of the medium; especially in concrete and cement technology, formation of a layer of water at the surface of a solid, such as cement, or aggregate, or of air-entraining agents at the air-water boundaries; the process by which a substance is adsorbed.

Aggregate
Granular material, such as sand, gravel, crushed stone, crushed hydraulic-cement concrete, or iron blast furnace slag, used with a hydraulic cementing medium to produce either concrete or mortar.

Aggregate Blending
The process of intermixing two or more aggregates to produce a different set of properties, generally, but not exclusively, to improve grading.

Aggregate Gradation
The distribution of particles of granular material among various sizes, usually expressed in terms of cumulative percentages larger or smaller than each of a series of sizes (sieve openings) or the percentages between certain ranges of sizes (sieve openings). See also 'Grading.'

Aggregate Interlock
The projection of aggregate particles or portion of aggregate particles from one side of a joint or crack in concrete into recesses in the other side of the joint or crack so as to effect load transfer in compression and shear and maintain mutual alignment.

Aggregate, Angular
Aggregate particles that possess well-defined edges formed at the intersection of roughly planar faces.

Aggregate, Coarse
See Coarse Aggregate

Aggregate, Dense-graded
Aggregates graded to produce low void content and maximum weight when compacted.

Aggregate, Fine
See Fine Aggregate

Aggregate, Gap-graded
Aggregate so graded that certain intermediate sizes are substantially absent.

Aggregate, Heavyweight
Aggregate of high density, such as barite, magnetite, hematite, limonite, ilmenite, iron, or steel, used to produce heavyweight concrete.

Aggregate, Lightweight
Aggregate of low density, such as (a) expanded or sintered clay, shale, slate, diatomaceous shale, perlite, vermiculite, or slag; (b) natural pumice, scoria, volcanic cinders, tuff, and diatomite; (c) sintered fly ash or industrial cinders, used to produce lightweight concrete.

Aggregate, Maximum Size
See Maximum Size of Aggregate

Aggregate, Nominal Maximum Size
In specifications for and descriptions of aggregate, the smallest sieve opening through which the entire amount of the aggregate is permitted to pass; sometimes referred to as 'maximum size (of aggregate).'

Aggregate, Open-graded
Concrete aggregate in which the voids are relatively large when the aggregate is compacted.

Aggregate-Cement Ratio
See Cement-Aggregate Ratio

Agitating Speed
The rate of rotation of the drum or blades of a truck mixer when used for agitation of mixed concrete.

Agitating Truck
A vehicle in which freshly mixed concrete can be conveyed from the point of mixing to that of placing; 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.

Agitation
The process of providing gentle motion in mixed concrete just sufficient to prevent segregation or loss of plasticity.

Agitator
A device for maintaining plasticity and preventing segregation of mixed concrete by agitation.

Air Content
The amount of air in mortar or concrete, exclusive of pore space in the aggregate particles, usually expressed as a percentage of total volume of mortar or concrete.

Air Void
A space in cement paste, mortar, or concrete filled with air; an entrapped air void is characteristically 1 mm or more in size and irregular in shape; an entrained air void is typically between 10 m and 1 mm in diameter and spherical (or nearly so).

Air-Entraining
The capabilities of a material or process to develop a system of minute bubbles of air in cement paste, mortar, or concrete during mixing.

Air-Entraining Agent
An addition for hydraulic cement or an admixture for concrete or mortar which causes air, usually in small quantity, to be incorporated in the form of minute bubbles in the concrete or mortar during mixing, usually to increase its workability and frost resistance.

Air-Entraining Cement
A cement that has an air-entraining agenda added during the grinding phase of manufacturing.

Air-Entrainment
The inclusion of air in the form of minute bubbles during the mixing of concrete or mortar.

Air-Meter
A device for measuring the air content of concrete and mortar.

Air-Water Jet
A high-velocity jet of air and water mixed at the nozzle, used in clean up of surfaces of rock or concrete, such as horizontal construction joints.

Alkali-Aggregate Reaction
Chemical reaction in mortar or concrete between alkalis (sodium and potassium) released from portland cement or from other sources, and certain compounds present in the aggregates; under certain conditions, harmful expansion of the concrete or mortar may be produced.

Alkali-Carbonate Reaction
The reaction between the alkalies (sodium and potassium) in portland cement binder and certain carbonate rocks, particularly calcite dolomite and dolomitic limestones, present in some aggregates; the products of the reaction may cause abnormal expansion and cracking of concrete in service.

Backer Rod
Foam cord that inserts into a joint sealant reservoir and is used to shape a liquid joint sealant and prevent sealant from adhering to or flowing out of the bottom of the reservoir.

Bag of cement
A quantity of cement; 42.6 kg in the United States, 39.7 kg in Canada; portland or air-entraining portland cement, or as indicated on the bag for other kinds of cement.

Ball Test
A test to determine the consistency of fresh concrete by measuring the depth of penetration of a steel ball. The apparatus is usually called a Kelly ball.

Bar
A member used to reinforce concrete, usually made of steel.

Bar Chair
An individual supporting device used to support or hold reinforcing bars in proper position to prevent displacement before or during concreting.

Bar Spacing
The distance between parallel reinforcing bars, measured center to center of the bars perpendicular to their longitudinal axis.

Bar Support
A rigid device used to support or hold reinforcing bars in proper position to prevent displacement before or during concrete placing.

Barrel of cement
A unit of weight for cement: (170.6 kg) net, equivalent to 4 US bags for portland or air-entraining portland cements, or as indicated by the manufacturer for other kinds of cement. (In Canada, 158.8 kg. net per barrel).

Base
A subfloor slab or 'working mat,' either previously placed and hardened or freshly placed, on which floor topping is placed in a later operation; also, the underlying stratum on which a concrete slab, such as a pavement, is placed.

Base Course
A layer of specified select material of planned thickness constructed on the subgrade or subbase below a pavement to serve one or more functions such as distributing loads, providing drainage, minimizing frost action, or facilitating pavement construction.

Batch
Quantity of concrete or mortar mixed at one time.

Batch Plant
Equipment used for batching concrete materials.

Batch Weights
The weights of the various materials (cement, water, the several sizes of aggregate, and admixtures) that compose a batch of concrete.

Batched Water
The mixing water added to a concrete or mortar mixture before or during the initial stages of mixing.

Batching
Weighing or volumetrically measuring and introducing into the mixer the ingredients for a batch of concrete or mortar.

Beam Test
A method of measuring the flexural strength (modulus of rupture) of concrete by testing a standard unreinforced beam.

Benkelman Beam
Static deflection measuring tool equipped with dial gauges able to detect slab deflection to 0.025 millimeters.

Binder
See Cement Paste

Bitumen
Any of various mixtures of hydrocarbons (as tar) often together with their non-metallic derivatives that occur naturally or are obtained as residues after heat-refining petroleum

Bituminous
Resembling, containing or impregnated with bitumen.

Blanking Band
A plastic scale, or computer-generated scale, 1.7 inches wide and 21.12 inches long representing a length of 0.1 miles on a profilograph trace. The opaque blanking strip, running the length of the scale and located at its midpoint, covers the profile trace. Typically, a bandwidth of 0.0 to 0.2 in. is used.

Bleeding
The self-generated flow of mixing water within, or its emergence from, freshly placed concrete or mortar.

Bleeding Rate
The rate at which water is released from a paste or mortar by bleeding, usually expressed as cubic centimeters of water released each second from each square centimeter of surface.

Blemish
Any superficial defect that causes visible variation from a consistently smooth and uniformly colored surface of hardened concrete. (See also Bug Holes, Efflorescence, Honeycomb, Laitance, Popout, Rock Pocket, Sand streak.)

Blended Cement
See Cement, Blended

Blended Hydraulic Cement
See Cement, Blended

Blistering
The irregular rising of a thin layer of placed mortar or concrete at the surface during or soon after completion of the finished operation.

Bond
The adhesion of concrete or mortar to reinforcement or other surfaces against which it is placed; the adhesion of cement paste to aggregate.

Bond Area
The interface area between two elements across which adhesion develops or may develop, as between concrete and reinforcing steel.

Bond Breaker
A material used to prevent adhesion of newly placed concrete from other material, such as a substrate.

Bond Hardness
The support (bond strength) that the metal matrix in a diamond saw blade segment provides to each diamond that is embedded within the matrix.

Bond Strength
Resistance to separation of mortar and concrete from reinforcing steel and other materials with which it is in contact; a collective expression for all forces such as adhesion, friction due to shrinkage, and longitudinal shear in the concrete engaged by the bar deformations that resist separation.

Bond Stress
The force of adhesion per unit area of contact between two surfaces such as concrete and reinforcing steel or any other material such as foundation rock.

Bonded Concrete Overlay
Thin layer of new concrete (2-4 inches) placed onto slightly deteriorated existing concrete pavement with steps taken to prepare old surface to promote adherence of new concrete.

Bonding Agent
A substance applied to an existing surface to create a bond between it and a succeeding layer, as between a bonded overlay and existing concrete pavement.

Box Out
To form an opening or pocket in concrete by a box-like form; Used for manholes, drainage inlets and other in-pavement objects..

Broom
The surface texture obtained by stroking a broom over freshly placed concrete. A sandy texture obtained by brushing the surface of freshly placed or slightly hardened concrete with a stiff broom.

Bug Holes
Small regular or irregular cavities, usually not exceeding 15 mm in diameter, resulting from entrapment of air bubbles in the surface of formed concrete during placement and compaction.

Bulk Cement
Cement that is transported and delivered in bulk (usually in specially constructed vehicles) instead of in bags.

Bulk Density
The mass of a material (including solid particles and any contained water) per unit volume, including voids.

Bulk Specific Gravity
The ratio of the weight in air of a given volume of a permeable material (including both permeable and impermeable voids normal to the material) at a stated temperature to the weight in air of an equal volume of distilled water at the same temperature.

Bulking Factor
Ratio of the volume of moist sand to the volume of the sand when dry.

Bull Float
A tool comprising a large, flat, rectangular piece of wood, aluminum, or magnesium usually 20 cm wide and 100 to 150 cm long, and a handle 1 to 5 m in length used to smooth unformed surfaces of freshly placed concrete.

Burlap
A coarse fabric of jute, hemp, or less commonly flax, for use as a water-retaining cover for curing concrete surfaces; also called Hessian.

Burlap Drag
Surface texture achieved by trailing moistened coarse burlap from a device that allows control of the time and rate of texturing.

Butt Joint
A plain square joint between two concrete slabs.

Calcareous
Containing calcium carbonate, or less generally, containing the element calcium.

Calcium Chloride
A crystalline solid, CaC12; in various technical grades, used as a drying agent, as an accelerator of concrete, a deicing chemical, and for other purposes.

Calcium Lignosulfonate
An admixture, refined from papermaking wastes, employed in concrete to retard the set of cement, reduce water requirement and increase strength.

Caliche
Gravel, sand, or desert debris cement by porous calcium carbonate or other salts.

California Bearing Ratio
The ratio of the force per unit area required to penetrate a soil mass with a 19.4 sq cm circular piston at the rate of 1.27 mm per min to the force required for corresponding penetration of a standard crushed-rock base material; the ratio is usually determined at 2.5 mm penetration.

California Profilograph
Rolling straight edge tool used for evaluating pavement profile (smoothness) consisting of a 25-ft frame with a sensing wheel located at the center of the frame that senses and records bumps and dips on graph paper or in a computer.

Capillary
In cement paste, any space not occupied by unhydrated cement or cement gel (air bubbles, whether entrained or entrapped, are not considered to be part of the cement paste).

Capillary Absorption
The action of surface tension forces which draws water into capillaries (i.e., in concrete) without appreciable external pressures.