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construction pathology: construction deterioration & building durability glossary

Construction deterioration & building durability glossary


Article & glossary hosted by A. Sebastian Engineering and Investigation Services


Casement
A window sash that swings open on side hinges; in-swinging are French in origin; out-swinging are from England.

Casing
Exposed molding or framing around a window or door, on either the inside or outside, to cover the space between the window frame or jamb and the wall.

Catalyst
An accelerator, activator or curing agent which chemically increases the rate of reaction in a coating.

Cathode
The negative terminal of an electrolytic cell which, in the corrosion process, is protected and not attacked.

Cathodic Protection
The reduction or prevention of corrosion of a metal surface caused by making it cathodic. This is accomplished by using a sacrificial anode (such as in zinc rich coatings or galvanizing) or by using impressed current.

Caulking
A mastic compound for filling joints and sealing cracks to prevent leakage of water and air, commonly made of silicone, bituminous, acrylic, or rubber-based material

Caustic
A strong base or alkaline material.

Caustic Soda
A common name for sodium hydroxide, a strong base or alkali.

Cavity
The cavity or air space between the brick and the positive water barrier at the exterior steel stud wall should not be less than two inches wide. Smaller cavities are permitted but often do not function well. The cavity acts to provide a buffer for wind driven rain and allows water that penetrates the brick veneer to flashing, the cavity should be kept clear of any obstructions that might allow water to bridge across. Mortar droppings should be prevented from falling into the cavity. When mortar droppings do enter the cavity they should be removed. Cavity spaces can be wider, but this will reduce the capacity of the brick ties. Construction tolerance on the cavity width should be limited to ± 1/2".

C/B RATIO
The ratio of the weight of water absorbed by a masonry unit during immersion in cold water to weight absorbed during immersion in boiling water. An indication of the probable resistance of brick to freezing and thawing. Also called saturation coefficient. See ASTM C67.

Cellosolve
Proprietary name for ethylene glycol monoethyl ether. A slow evaporating, water miscible, relatively strong solvent often used in epoxy coatings.

cement/si-'ment/ also /'sE-ment/
Function: noun
Etymology: Middle English "sement", from Middle French "ciment", from Latin "caementum" stone chips used in making mortar, from "caedere" to cut
1. Powder of alumina, silica, lime, iron oxide, and magnesium oxide burned together in a kiln and finely ground; used as an ingredient of mortar, grout and concrete; also: ather mixtures used for similar purposes. See ASTM C150 (Portland cement), C91 (masonry cement), C595 (blended hydraulic cement)
2. Concrete; this is an improper usage!
3. Something serving to unite firmly
4. Plastic composition made especially of zinc or silica for filling dental cavities
5. The fine-grained groundmass or glass of a porphyry

Variations:
ce·ment·er noun
fer·ro-ce·ment
port·land cement
masonry cement
bituminous cement
hydraulic cement
Keene's cement
oil-well cement
rubber cement

cement/si-'ment/ also /'sE-ment/
Function: verb, transitive senses 1. To unite or make firm by or as if by cement 2. To overlay with concrete Function: verb, intransitive senses : to become cemented

Cementitious Coatings
A coating containing Portland cement as one of its components held on the surface by a binder.

cementitious material
Having the property of or acting like cement (ie binding substances together when reacting with water), such as certain limestones and tuffs when used in the surfacing of roads, but also Portland cement and fly ash in concrete, mortar or grout mixes

cement-modified soil
The addition relatively small amounts of cement (1% to 2%) to fine-grained soils to reduce the liquid limit, plasticity index, volume change and water-retaining tendency. The effect of the cement is to bring individual soil particles into aggregations, thus artificially adjusting the grading of the soil, and icreasing its load bearing capacity and shearing strength. This is different from cement which contains more cement Also called "soil stabilization"

cement mortar
Mortar containing up to four parts of sand, one of cement, and adequate water

cement plug
Hardened cement material filling a portion of a borehole. Long

CENTERING
Temporary formwork for the support of masonry arches or lintels during construction. Also called center(s)

Centipoise
One hundredth of a poise which is a unit of measurement for viscosity. Water at room temperature has a viscosity of 1.0 Centipoise.

CERAMIC COLOR GLAZE
An opaque colored glaze of satin or gloss finish obtained by spraying the clay body with a compound of metallic oxides, chemicals and clays. It is burned at high temperatures, fusing glaze to body making them inseparable. See ASTM C126

CFM (cfm)
Cubic feet per minute

Chalking
The formation of a friable powdery coating on the surface of a paint film, generally caused by exposure to ultraviolet radiation resulting in a loss of gloss.

CHASE
A continuous recess built into a wall to receive pipes, ducts, etc.

Check rail
The bottom horizontal member of the upper sash and the top horizontal member of the lower sash which meet at the middle of a double-hung window.

Checking
Cracks in the surface of a paint film.

Chipping
Small pieces of paint removed from the surface, typically a sign of physical damage incurred in shipping or handling. Use of a surface tolerant primer for touch up followed by the same finish coat generally solves the problem.

Chlorinated Hydrocarbon
A class of strong, fast evaporating, nonflammable solvents such as carbon tetrachloride, methylene chloride or trichloroethylene.

Chlorinated Rubber
A coating resin formed by the reaction of rubber with chlorine gas. Often used for chemical or water resistant properties.

CLAY
A natural, mineral aggregate consisting essentially of hydrous aluminum silicate; it is plastic when sufficiently wetted, rigid when dried and vitrified when fired to a sufficiently high temperature.

CLAY MORTAR-MIX
Finely ground clay used as a plasticizer for masonry mortars.

Clean and Dry
Rather than a method, the requirement for Clean and Dry describes the condition of the surface prior to painting.
The surface shall be clean, dry, and free of oil, grease, wax, form oils, and any other contaminant that may effect the adhesion of the coating. For best results and high performance requirements remove latencies and contaminants from precast and cast-in-place concrete by abrasive blasting or high pressure water blasting.
Dry means that the substrate contains less then 15% moisture.
Concrete should be cured at least 28 days and mortar joints at least 15 days @ 75 F and 50% RH.
See also: ASTM D 4263 - 83; ASTM D 4258 - 83; ASTM D 4259 - 83; ASTM D 4260 - 83; ASTM D 4261 - 83; ASTM D 4662 - 83

Cleaner
A detergent, alkali, acid or similar contamination removing material, which is usually water borne.

CLEAR CERAMIC GLAZE
Same as Ceramic Color Glaze except that it is translucent or slightly tinted, with a gloss finish.

Clerestory
A window in the upper part of a lofty room that admits light to the center of the room.

CLIP
A portion of a brick cut to length.

CLOSER
The last masonry unit laid in a course. It may be whole or a portion of a unit.

CLOSURE
Supplementary or short length units used at corners or jambs to maintain bond patterns.

Coal Tar
A dark brown to black bituminous material produced by the destructive distillation of coal.

Coal Tar Epoxy
A coating in which the binder or vehicle is a combination of coal tar and epoxy resins.

Coalescence
The formation of resinous or polymeric material when water evaporates from an emulsion or a latex system, permitting contact and fusion of adjacent particles; fusing or flowing together of liquid particles.

Coat
The layer of paint (or even plaster or aspphalt) applied to a surface in a single application to form a film when dry.

coating
Material applied to a surface in order to protect, preserve, seal, decorate, or smooth the substrate.

coating asphalt
Weather-resistant layer of asphalt applied to a roofing material surface during manufacture. Surfacing material such as aggregate is embeded in this asphalt.

Coating System
A number of coats separately applied, in a predetermined order, at suitable intervals to allow for drying and curing, resulting in a completed job.  

Cobwebbing
Premature drying of a coating during spraying causing a spider web effect.  

Cohesion
The forces which bind the particles of a paint film together into a continuous film.  

Cold Rolled Steel
Low carbon, cold-reduced, sheet steel. Differs from hot rolled steel by the absence of mill scale.

COLLAR JOINT
The vertical, longitudinal joint between wythes of masonry.

Color Fast
Nonfading.

Color Retention
The ability to retain its original color during weathering or chemical exposure.

COLUMN
A vertical member whose horizontal dimension measured at right angles to the thickness does not exceed three times its thickness.

Combustible Liquid
Any liquid having a flash point at or above 100 F (37.8 C)

commercial quarry
Term that includes open mining for aggregate or limestone for industrial and agricultural purposes.

commercial sampling of aggregates or coal
Laboratory procedures intended to produce an accuracy such that if a large number of samples are taken from a single lot of aggregates or coal, 95 out of 100 test results will be within + or - 10% of the average of these samples.

comminution
The reduction of a rock to progressively smaller particles by natural methods (weathering, erosion, or tectonic movements) or manufacturing processes (breaking, crushing, or grinding by mechanical means). Syn: pulverization; trituration.

compaction curve
The curve showing the relationship between the density (dry unit weight) and the water content of a soil for a given compactive effort. Syn: moisture-density curve

compaction equipment
Machines, such as rollers, to expel air from a soil mass and so achieve a high density. Smooth-wheel rollers are best for gravels, sands, and gravels-and-clay soils with reasonably high moisture contents. Pneumatic-tired rollers are best for clays with reasonably high moisture content, and sheepsfoot rollers are the best for clays with low moisture content. See also: superficial compaction

compaction test
A basic laboratory compacting procedure to determine the optimum water content at which a soil can be compacted so as to yield the maximum density (dry unit weight). The method involves placing (in a specified manner) a soil sample at a known water content in a mold of given dimensions, subjecting it to a compactive effort of controlled magnitude, and determining the resulting unit weight (ASCE, 1958, term 74). The procedure is repeated for various water contents sufficient to establish a relation between water content and unit weight. The maximum dry density for a given compactive effort will usually produce a sample whose saturated strength is near maximum. Syn: moisture-density test

compact rock
A rock so closely grained that no component particles or crystals can be recognized by the eye.

Compatibility
The ability to mix with or adhere properly to other coatings without detriment.

Condensation
The deposit of water vapor from the air on any cold surface whose temperature is below the dew point, such as a cold window glass or frame that is exposed to humid indoor air.

Conduction
Heat transfer through a solid material by contact of one molecule to the next. Heat flows from a higher-temperature area to a lower-temperature one

Conical Mandrel
An instrument used to evaluate a coating's resistance to cracking when bent over a specified radius.

Continuity
means more than being without holes. Because the component that performs the role of the air barrier changes from the wall to the window to the roof, continuity means that all these assemblies must be connected together so as to ensure that there is no break in the airtightness of the envelope

con·trac·tion/k&n-'trak-sh&n/
Function: noun
Date: 15th century
Also:
- con·trac·tion·al /-shn&l, -sh&-n&l/ adjective
- con·trac·tive /k&n-'trak-tiv, 'kän-"/ adjective
- con·trac·tion·ary /k&n-'trak-sh&-"ner-E/ adjective
Thermal action where the size of an object is reduced when cooled; the opposite of expansion.

contamination
The deposit, absorption, or adsorption of biological or chemical agents (including the growth of bacteria or fungi)on or by materials, structures, areas, personnel, or objects

Convection
A heat transfer process involving motion in a fluid (such as air) caused by the difference in density of the fluid and the action of gravity. Convection affects heat transfer from the glass surface to room air, and between two panes of glass.

COPING
The material or masonry units forming a cap or finish on top of a wall, pier, pilaster, chimney, etc. It protects masonry below from penetration of water from above.

CORBEL
A shelf or ledge formed by projecting successive courses of masonry out from the face of the wall.

cost escalation
change in estimated cost of a project due to inflation, aggravated conditions, etc.

COURSE
One of the continuous horizontal layers of units, bonded with mortar in masonry.

crack/'krak/
Function: verb
Etymology: Middle English crakken, from Old English "cracian"; akin to Old High German "chrahhOn" to resound
Date: before 12th century
intransitive senses
transitive senses
1. a: to break so that fissures appear on the surface or through the element ; b: fracture caused by the effects of stress(es) on weak or weakened parts of a member or material. 2. to impair seriously or irreparably 3. to subject (hydrocarbons) to cracking (to break a large, complex compound into simpler compounds) 4. to break up (chemical compounds) into simpler compounds by means of heat

Crack length
Total outside perimeter of window vent. Used in figuring air infiltration during AAMA certification testing.

CRF
Condensation Resistance Factor. An indication of a window's ability to resist condensation. The higher the CRF, the less likely condensation is to occur

culls
something rejected, especially as being inferior or worthless, i.e. masonry units which do not meet the standards or specifications and have been rejected.

curtain wall as
Exterior non-loadbearing wall not wholly supported at each story. Such walls may be anchored to columns, spandrel beams, floors or bearing back-up walls, but not necessarily built between structural elements. Curtain walls must be capable of supporting their own weight for the height of the wall. In contrast, panel walls are required to be self-supporting between stories. Both walls resist lateral forces such as wind pressures and must transfer these forces to adjacent structural members.

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