| Hand
Float |
A smaller handheld version
of the bull float, ranging in length from 12 to 18 inches. Especially
useful for floating along the perimeter of forms or to work in tight spots. |
| Hard-Troweled
Finish |
Surface finish obtained
by using a trowel with a steel blade for final finishing of concrete.
Often used where a smooth, hard, flat surface is desired. |
| Heat
of Hydration |
The quantity of heat expressed
in calories per gram, evolved upon complete hydration of portland cement
at a given temperature. |
| High-Build
Coating |
A protective or decorative
coating that produces a thick film (usually greater than 10 mils) in a
single coat. |
| High-Pressure
Water Blasting |
A process for cleaning
or roughening concrete surfaces using a stream of water delivered at high
pressure. |
| HRM
High Reactivity Metakaolin |
Refined form of an ASTM
C618, Class N (natural) pozzolan. A high performance, mineral admixture,
similar in performance to silica fume, additionally comparable in cost.
Pure white powdered in form will, not effect the natural color or darken
concrete as silica fume does. Suitable for high-performance color matching
in architectural concrete. Dosage at 5% to 10%, of cement by weight. No
bleed water, better finishability, more creamy, cleanup is easier with
slightly higher 28 day strengths and 25% - 35% less plasticizer is required
than silica fume. |
| High-Volume
Low-Pressure (HVLP) Sprayer |
A spraying device that
applies high-solids paints and coatings at low pressure and low velocity,
to reduce overspray. |
| Holding
Period |
Period In the manufacture
of concrete products, the period between completion of casting and the
introduction of additional heat or the steam curing period. |
| Hopper
Gun |
A gravity-fed system for
spray application of coatings or toppings. The material is placed in a
hopper attached to a spray gun, which is powered by an air compressor.
Often used to apply spray-down systems. |
| Hover
Trowel |
A patented lightweight
power trowel developed specifically for precision finishing of epoxy,
polymer modified, and cementitious overlay systems. |
| Hydration |
The chemical reaction between
cement and water that causes concrete or other cement-based materials
to harden. |
| Hydraulic
Cement |
A cement that is capable
of setting and hardening under water due to interaction of water and the
constituents of the cement (ASTM 219). |
| Hydrogenesis
|
Another term for condensation.
The term is especially applied to base and soil substrates under highway
pavements. where the barometric pump causes the inhalation of humid air,
which then condenses in those structures, causing an ever increasing moisture
content and sometimes instability. |
| Hydrologic
Cycle |
The Hydrologic Cycle consists
of the evaporation of water from oceans and other bodies of open water;
condensation to produce cloud formations; precipitation of rain, snow,
sleet or hail upon land surfaces; dissipation of rain or melted solids
by direct run-off into lakes and by seepage into the soil. Thereby producing
a continuing endless source of water in the sub-grade. |
| |
| Impeller |
An object that drives forward;
propels. |
| Impermeable |
The ability of a material
or product to reduce or eliminate gaseous transmissions through it's mass;
measured as the rate of Water Vapor Transmission (WVT). Note: Not all
materials that are waterproof are vaporproof; all materials that are vaporproof
are inherently waterproof. |
| Impervious |
Resistant to movement of
water. |
| Initial
Set |
A degree of stiffening
of the cement and water mixture. This is a degree lees than final set
and is generally stated as an empirical value, indicating the time in
hours and minutes required for a cement paste to stiffen sufficiently
to resist to an established degree the penetration of a weighted test
needle. (Refer to ASTM C191 or C286 for weight and penetration data.) |
| Initial
Stress |
In prestressed concrete,
the stresses occurring in the prestressed members before any losses occur. |
| In
Situ |
Natural undisturbed soil
in place. |
| Integral
Color |
A coloring agent premixed
into fresh concrete or cementitious toppings before placement. |
| Iron
Oxide |
An inorganic pigment often
used to color decorative coatings and toppings. |
| |
| Jacking
Equipment |
In prestress concrete,
the device used to stress the tendons. |
| Jacking
Force |
The temporary force exerted
by the jacking device which introduces tension into the tendons. Jacking
Stress In prestress concrete, the maximum stress occurring in a tendon
during stressing. |
| Joint
(control, expansion, or isolation) |
Formed, sawed, or tooled
groove in a concrete slab used to regulate the location of cracking (control
joint) or to allow expansion or movement of adjoining structures. In decorative
concrete, joints can also double as delineating design elements in a pattern.
|
| Joint
Filler |
A compressible material
used to fill a joint to prevent the infiltration of debris.
|
| |
| Kaolin
|
A type of clay from which
kaolinite is extracted. Also called "china clay". Engelhard
has an abundant reserve of kaolin in central Georgia, U.S.A., located
close to its manufacturing facilities, and takes precautions to assure
that its mines are reclaimed in an environmentally sound manner. |
| Kaolinite
|
A naturally occurring
crystalline mineral that is extracted from kaolin. |
| Keene's
Cement |
A finely ground high density
plaster composed of anhydrous, (calcined or "dead burned") gypsum,
the set of which is accelerated by the addition of other materials. |
| Kelly
Ball |
A device for determining
the consistency of fresh concrete. It is sometimes used as an alternative
to the slump test. |
| Kerf
|
A cut in a concrete surface
made by a saw or router. |
| Kneeboards
|
Boards used by concrete
finishers to kneel on when hand floating or troweling concrete flatwork. |
|
Knock-down finish |
Achieved by applying a
decorative topping with a hopper gun and then using a trowel to “knock-down”
the material to produce a smooth or lightly textured surface.
|
| |
| Laitance |
A thin layer of fine, loosely
bonded particles on the surface of fresh concrete, caused by the upward
movement of water. Laitance must be removed before application of a decorative
coating or topping. |
| Lift |
Layer of concrete. |
| Lime
|
Also known as "lime",
calcium hydroxide is a chemical compound (Ca(OH)2) formed as a byproduct
of cement hydration. MetaMax® reacts with calcium hydroxide to create
additional cementitious bonds within concrete. |
| Liquid
Limit |
The water content at which
soil passes from a plastic to a liquid state. |
| Liquefaction |
The change of state to
a liquid. Term used instead of condensation in reference to substances,
which are usually gaseous. |
| Loam |
A soft, easily worked soil
containing sand, silt, clay and decayed vegetation. |
| |
| Magnetite |
An aggregate used in heavy
weight concrete, consisting primarily of ferrous metaferrite (Fe304).
A black magnetic iron ore with a specific gravity of approximately 5.2
and a Mohs hardness of about 6. |
|
Marbleize |
To give concrete surfaces
the look and gloss of marble, through a combination of color layering
and finishing techniques. |
| Margin
trowel (also pointer or pointed mason’s trowel) |
A steel trowel with a small,
rectangular flat blade about 5 to 8 inches in length and a short handle.
It has multiple uses, including scraping off concrete from finishing tools
and applying patching materials. |
| Marl |
A calcareous clay, containing
approximately 30 to 65 percent calcium carbonate (05003), found normally
in extinct fresh wafer basins, swamps, or bottoms of shallow lakes. |
| Masking |
Covering select areas of
a concrete surface with an adhesive stencil, tape, or other medium before
applying a decorative treatment that will affect only the exposed areas.
|
| Masonry
Cement |
Hydraulic cement manufactured
for use in mortars for masonry construction. Normally a blend of two or
more of the following materials: portland cement, natural cement, portland-pozzolan
cement, hydraulic lime, slag cement, hydrated lime, pulverized limestone,
talc, chalk, pozzolan, clay or gypsum; also may include air en-training
additions. |
| Mass
Concrete |
Any large volume of concrete
cast in place intended to resist applied loads by virtue of mass. Generally
a monolithic structure incorporating a low cement factor with a high proportion
of large coarse aggregate. |
| Mass
Curing |
Adiabatic curing, using
sealed containers. |
|
Material safety data sheet (MSDS) |
Information sheets containing
pertinent chemical ingredients, product handling and safety guidelines. |
| Maximum
Size Aggregate |
Aggregate whose largest
particle size is present in sufficient quantity to affect the physical
properties of concrete; generally designated by the sieve size on which
the maximum amount permitted to be retained is 5 or 10 percent by weight. |
| Membrane |
Formed over a concrete
surface to provide protection and enhance color. Typically clear plastic
like acrylic, polyurethane or epoxy. |
|
Microtopping |
An ultra-thin polymer-based
decorative topping, generally less than 1/4-inch total thickness. Typically
applied by trowel or squeegee, and given a texture or smooth finish. Pigments
can be incorporated into the mix or broadcast onto the surface for a marbleized
appearance. |
|
Mil |
A measurement equal to
1/1,000 (0.001) inch. Commonly used to denote coating thickness. |
| mix
design |
Specific proportions of
ingredients (cement, aggregates, water, and admixtures) used to produce
concrete suited for a particular set of job conditions. |
| Mixer |
Equipment used for mixing
or blending the materials used in the manufacture of concrete, grout or
mortar. |
| Mixing
Speed |
Rate of mixer drum rotation
or that of the paddles in a pan, open-top, or trough type mixer, when
mixing a batch; expressed in revolutions per minute (rpm) or in peripheral]
feet per minute of A point on the circumference at maximum diameter. |
| Mixing
station |
A designated work area
outfitted with all the equipment and supplies needed to mix materials
properly and efficiently.
|
| Mixing
Time |
For stationary mixers,
mixing time is calculated in minutes from the completion of charging the
mixer until the beginning of discharge; for truck mixer, time is calculated
in total minutes at a specified mixing speed. the period during which
materials used in a batch of concrete are combined by the mixer.
|
| Mockup |
An architectural concrete
sample made using the same materials and methods proposed for an actual
project. Often required for quality assurance on large projects, to ensure
that architectural requirements and industry tolerances are met. The size
should be sufficient to adequately demonstrate all decorative treatments.
|
| Modulus
of Elasticity |
A measure of the resistance
of material to deformation. the ratio of normal stress corresponding strain
for tensile or compressive stresses below the proportional limit of the
material; elastic modulus is denoted by the symbol "2". |
| |
| Neat
Cement |
Unhydrated hydraulic cement. |
| Neat
Cement-Paste |
A mixture of water and
hydraulic cement, both before and after setting and hardening. |
|
Neutralize |
To return concrete to the
proper pH after acid etching, generally by washing the surface with a
mixture of water and ammonia or sodium carbonate. Ideal pH is 7.0 (neutral),
but a pH range of 6.0-9.0 is acceptable for most coatings. ASTM D 4262,
"Standard Test Method for pH of Chemically Cleaned or Etched Concrete
Surfaces," covers the procedure for determining the acidity or alkalinity
of concrete surfaces prepared by chemical cleaning or etching prior to
coating application. |
| No-Fines
Concrete |
A concrete mixture in which
only the coarse gradation (3/8' to 3/4' normally) of aggregate issued. |
| Non-agitating
Unit |
A truck-mounted unit for
transporting ready-mixed concrete short distances, not equipped to provide
agitation (slow mixing) during delivery. |
| Non-evaporable
Water |
The water in concrete which
is irremovable by oven drying; chemically combined during cement hydration. |
|
Notched-squeegee |
A rubber squeegee with
notches or serrations on one or both edges. Used for smooth and consistent
spreading of epoxy resin products or other low-viscosity coatings. |
| |
| Opacity |
The
ability of a coating to hide the color of the underlying surface. |
| Optimum
Moisture Content |
That
percent of moisture at which the greatest density of a soil can be obtained
through compaction. |
| Overvibration |
Excessive
vibration of freshly mixed concrete during placement-causing segregation. |
|
Overlay |
A
bonded layer of material, ranging from 1/4 to 1 inch or more in thickness,
placed on existing concrete surfaces to beautify, level, or restore. |
| |
| Particle-Size
Distribution |
Particle distribution of
granular materials among various sizes; for concrete material normally
designated as gradation. Usually expressed in terms of cumulative percentages
smaller or larger than each of a series of sieve openings or percentages
between certain ranges of sieve openings. |
| Pass |
A working trip or passage
of an excavating, grading or compaction machine from point A to point
B. |
| Pea
Gravel |
Portion of concrete aggregate
passing the 3/8' sieve and retained on a No.4 sieve. |
| Peeling |
A process in which thin
flakes of matrix or mortar are broken away from concrete surface; caused
by adherence of surface mortar-to forms as forms are removed, or to trowel
or float in portland cement plaster. |
| Penetrating
sealer |
A sealer with the ability
to penetrate into the concrete surface to increase water repellency and
resist stains. Often used on decorative concrete to provide invisible
protection without changing the surface appearance. |
| Permeability |
The degree to which a
membrane or coating will allow the passage or penetration of a liquid
or gas. |
| Pining |
Development of relatively
small cavities in a concrete surface, due to phenomena such as cavitation
or corrosion. |
| Plane
of Weakness |
The plane along which a
structure under stress will tend to fracture; may exist because of the
nature of the structure and its loading, by accident, or by design. |
| Plastic |
A condition of freshly
mixed concrete. mortar or cement -paste indicating that it is workable
and readily re-moldable, is cohesive, and has an ample content of fines
and cement but is not over wet. |
| Plastic
concrete |
Freshly mixed concrete
that is capable of being molded or shaped. |
| Plastic
Consistency |
Condition in which concrete,
mortar, or cement paste will sustain deformation continuously in any direction
without rupture. |
| Plasticity |
Property of freshly mixed
concrete, cement paste or mortar which determines its ease of molding
or resistance to deformation. |
| Plastic
shrinkage |
Plastic shrinkage occurs
when water evaporates from concrete during the curing process. This shrinkage
can generate cracks through which water can penetrate into concrete and
promote deterioration. MetaMax® can reduce plastic shrinkage by reducing
the water demand of the concrete. |
| Plasticizer |
A material that increases
the workability or consistency of a concrete mixture, mortar or cement
paste. |
| Polymer-modified
overlay |
A cement-based overlay
with polymer resins added to improve performance, wear resistance, and
aesthetic qualities. Overlay manufacturers use different types of polymer
resins, often blending them to produce proprietary products with unique
characteristics. Many of today’s decorative overlays use acrylics
or vinyl blends because these resins provide excellent bond strength and
UV resistance. |
| Porosity |
The ratio of the volume
of voids in the material to the total volume of the material, including
the voids, usually expressed as a percentage. |
| Portland
cement |
A powder - formed by the
calcination of limestone, clay and shale - that hardens and becomes cementitious
when it reacts with water and which, when mixed with aggregate, can be
used as the structural material known as portland cement concrete. Additional
specifications for portland cement are in ASTM C150. White portland cement
is made with selected raw materials to control its color. |
| Portland-Pozzolan
Cement |
The product obtained by
intimately intergrinding a mixture of portland-cement clinker and pozzolan,
or an intimate and uniform blend of portland cement and fine pozzolan.
|
| Pozzolan |
A siliceous, or siliceous
and aluminous material, which in itself possesses little or no cementitious
value but will, in a finely divided form, such as a powder or liquid and
in the presence of moisture, chemically react with calcium hydroxide at
ordinary temperatures to form permanent, insoluble compounds possessing
cementitious properties. |
| |
| Quicksand |
Fine sand or silt that
is prevented from settling firmly together by upward movement of underground
water. |
| |
| Raveling |
The dislodging of aggregate
at the edges of joints or scored patterns in concrete, generally caused
by sawcutting joints too soon after concrete placement. |
| Reactivity |
Capable of forming chemical
compounds. As a highly reactive metakaolin, MetaMax® reacts efficiently
with portland cement to improve the strength and durability of concrete. |
|
Rebar (or reinforcing bars) |
Ribbed steel bars installed
in cast-in-place concrete to provide flexural strength. Rebar come in
various diameters and strength grades. |
|
Reentrant corner |
An angle in a concrete
slab that points inward. Often vulnerable to cracking, unless a control
joint is installed. |
|
Reflection cracking |
The occurrence of cracks
in overlays and toppings that coincide with the location of existing cracks
in the substrate. |
| Refractory
Concrete |
Concrete having refractory
properties, suitable for use at high temperatures. Calcium-aluminate cement
and refractory aggregates are normally used for the manufacture of this
product. |
| Reinforced
Concrete |
A. Concrete in which
reinforcement, other than that provided for temperature changes for
shrinkage, has been embedded in such a- manner that the two materials
act together in resisting forces.
B. Concrete in which steel bars have been placed to
sustain the tensile stresses. |
|
Release agent |
A powder or liquid parting
agent applied to stamping mats or texturing skins before stamping to keep
the mats from sticking to fresh overlay or concrete surfaces. |
| Retardation |
Delaying the hardening
or strength gain of fresh concrete, mortar or grout. |
| Retarder |
An admixture which extends
the setting time of cement paste, and therefore of mixtures such as concrete,
mortar, or grout. |
| Retempering |
The addition of water and
remixing of concrete which has started to stiffen: usually not allowed
as it may affect the ultimate strength. |
| Revibration |
Delayed vibration of concrete
that has already been placed and consolidated. Most effective when done
at the latest time a running vibrator will sink of its own weight into
the concrete and make it plastic and workable again. |
| Rock
Pocket |
Area or portion of hardened
concrete which is deficient in mortar and consisting primarily of coarse
aggregate and open voids; caused by insufficient consolidation or separation
during placement, or both; by leakage from form. |
| Rod
(tamping) |
A round, straight steel
rod, 5/8' in diameter and approximately 24' in length, having the tamping
end rounded into a hemispherical tip, the diameter of which is 5/8'. |
| Rustication
strip |
A strip made of wood, polystyrene,
or plastic that’s fastened to forms or form liners to impart architectural
details to wall surfaces. |
| |
| Sack |
A quantity of cement: 94
Ibs. in the United States, 87.5 Ibs. in Canada, for portland or air entraining
portland cement, or as indicated on the sack for other kinds of cement. |
| Sacking |
Removing or alleviating
defects on a concrete surface by applying a mixture of sand and cement
to the moistened surface and rubbing with a coarse material such as burlap. |
| Sacrificial
coating |
A final floor finish or
wax designed to protect the sealer or topcoat from wear. Usually applied
by mop or floor buffer in several coats to act as a shock absorber to
scuffs, scratches, and grime. |
|
Salt finish |
textured, decorative finish
obtained by broadcasting rock salt onto fresh concrete and then using
a roller or float to press the salt particles into the surface. After
the concrete sets, the salt is washed away to reveal a speckled pattern
of shallow indentations. |
| Sand |
A cohesiveness aggregate
of round and angular fragments of rock with a particle size between 2.0
and .05 mm. |
|
Sandblast stenciling |
A technique for patterning
existing concrete surfaces by applying resilient adhesive stencils followed
by sandblasting to lightly remove concrete in only the exposed areas. |
|
Sandblasting |
A method of abrading or
profiling a surface with a stream of sand ejected from a nozzle at high
speed by compressed air. |
| Saponification |
The deposit of a gray scum
or gray dust on the inside surface of a subgrade wall or floor; as the
result of moisture moving through the concrete and washing certain chemicals
from the concrete mass. |
| Saturated
surface dry (SSD) |
Condition of concrete when
the permeable voids are filled with water but no water is on the exposed
surface. |
| Sawcutting |
Using a concrete saw with
abrasive blades or disks to cut joints or score patterns into hardened
concrete. |
| Scaling |
The flaking or breaking
away of a hardened concrete surface, often due to exposure to freezing
and thawing. |
| Scarifier |
Milling equipment used
to clean and profile concrete surfaces or to remove existing coatings.
Uses rotary impact cutters held at a right angle to the surface. |
| Screed |
1. Firmly placed grade
strips or side forms which are set as guides for a straight edge to bring
the surface of concrete to the required elevation.
2. To strike off concrete above the desired level.
|
| Screen
(or Sieve) |
A metallic sheet or plate,
woven wire cloth, or similar device, with regularly spaced openings of
uniform size, mounted in a suitable frame or holder for use in separating
material according to size. |
|
Sealer |
Solvent- or liquid-based
material used to protect and enhance the appearance of decorative concrete. |
| Seeding |
Broadcasting decorative
aggregates on the surface of freshly placed concrete or toppings. |
| Segregation |
The tendency for the coarse
particles to separate from the finer particles in handling. In concrete,
the coarse aggregate and drier material remains behind and the mortar
and wetter material flows ahead. This also occurs in a vertical direction
when wet concrete is over vibrated or dropped vertically into the forms,
the mortar and wetter material rising to the top. In aggregate, the coarse
particles roll-to the outside edges of the stockpile. |
|
Self-leveling overlay |
A flowable, polymer-modified
cementitious topping with the ability to self level without troweling.
Used to smooth and level existing concrete surfaces. Can also be enhanced
by staining, dying, or sawcutting. |
|
Set |
The condition reached by
concrete when plasticity is lost, usually measured in terms of resistance
to penetration or deformation. Initial set refers to concrete that has
reached first stiffening. Final set occurs when concrete attains full
rigidity. |
| Setting
Time |
The time
required for a specimen of cement paste, mortar or concrete, prepared
and tested under standardized conditions to attain a specified degree
of rigidity with particular reference to initial and final setting time. |
| |
|
Tack |
The stickiness or adhesiveness
of a material. |
| Tamper
(or pounder) |
A handheld impact tool
used to firmly press stamping mats or texturing skins into fresh concrete
to ensure a complete imprint. |
| Technical
data sheet |
Contains important specifications
and manufacturer guidelines for product usage. Includes such data as coverage
rates, recommended applications, product limitations, surface preparation
guidelines, mix ratios and required mixing times, pot life, application
procedures, cure times, performance data, and precautions. |
| Temperature
Reinforcement |
Reinforcement used to carry
temperature stresses. |
| Temperature
Rise |
The increase of concrete
temperature caused by heat of hydration and heat from other sources. |
| Texture
roller |
A cylindrical tool similar
in appearance to a paint roller used to impart a stonelike texture to
stenciled concrete. It is rolled over the stencil and the fresh concrete
to texture only the exposed surfaces. |
|
Texturing |
Giving concrete or overlay
surfaces a texture without leaving deep pattern lines. |
| texturing
skins |
Flexible skins for adding
seamless textures to concrete surfaces. Generally thinner and more pliable
than stamping mats. Often used to texture slab perimeters and vertical
faces, such as stair risers. Can also be used to fix blemishes from nonuniform
stamping. |
| Tilt-up |
A method of concrete construction
such as where members are cast horizontally near their eventual position,
usually on a recently placed slab, and then tilted into place after removal
of forms. |
|
Tint |
A diluted color wash used
to add hints of color to decorative concrete. |
| Transit-Mixed
Concrete |
Concrete produced from
a central-batching plant, where the materials are proportioned and placed
in truck-mixers for mixing enroute to the job or after arrival there. |
|
Translucent |
A type of finish were the
coating has some level of transparency. |
| Tremie |
A pipe through which concrete
may be placed under water, having at its upper end a hopper for filling,
and a bale which permits handling of the assembly by a derrick. |
|
Trowel |
A flat, broad-bladed steel
hand tool used to compact the paste layer at the surface and provide a
smooth, flat finish. Also useful for applying topping or repair materials.
Available in different shapes (with rounded or square edges) and lengths
(ranging from 8 to 24 inches). Smaller trowels are useful for borders,
work in restricted areas, or to work in flashing accents of dry-shake
color hardener. |
|
Trowel finish |
The smooth or lightly textured
surface finish obtained by troweling. |
| Truck
Mixer |
A concrete mixer capable
of mixing concrete in transit when mounted on a truck chassis. |
| |
| Ultimate
Strength |
The maximum resistance
to loads that a structure or member is capable of developing before failure
occurs, or, with reference to cross sections of members, the largest axial
force, shear or moment a structural concrete cross section will support.
|
| Unit
Water Content |
The quantity of water per
unit volume of freshly mixed concrete, often expressed as gallons or pounds
per cubic yard. This is the quantity of water on which the water cement
ratio is based, and does not include water absorbed by the aggregate.
|
| |
|
Vapor barrier |
A moisture-impervious material,
such as plastic sheeting, placed on the subbase under a concrete slab
to help prevent moisture vapor transmission. |
| Vacuum
|
Containing air or other
gas at a reduced pressure. |
| Vapor
Pressure |
The pressure exerted by
a vapor that is calculated based upon relative humidity and temperature.
The higher the humidity and higher temperature, in degrees Fahrenheit,
the greater the vapor pressure exerted. |
| Vapor
|
When a liquid changes to
a gaseous form. The ability of the gas to hold moisture will reduce as
temperatures reduce; more moisture can be contained in the gas as the
temperatures increase. |
| Vaporproof |
A material that is totally
immune to the passage of a gas under pressure. Any material that is truly
vaporproof will inherently be waterproof. |
|
Vertical stamped concrete |
A decorative finish for
walls and other vertical surfaces using a lightweight cementitious overlay
formulated to be applied at thicknesses of up to 3 inches without sagging.
While the overlay is still plastic, it can be stamped or hand carved to
produce deep-relief stone or masonry wall textures. After the material
dries, acid stains or dyes can be sprayed or sponged onto the surface
to give it the multi-toned look of natural stone. |
| Vibration |
Energetic agitation of
concrete to assist in its consolidation, produced by mechanical oscillating
devices at moderately high frequencies.
A. External vibration employs a device attached to the forms and is
particularly applicable to the manufacture of precast items and for
the vibration of tunnel lining forms.
B. Internal vibration employs an element which can be inserted into
the concrete; and is more generally used for cast-in-place construction.
|
| Vibratory
Force |
Uses a mechanism, usually
engine-driven, to create a downward force in addition to the machine's
static weight. The vibrating mechanism is usually a rotating eccentric
weight or piston/spring combination (in rammers). |
| Vicat
Apparatus |
A penetration device used
to determine the setting characteristics of hydraulic cements. |
| Viscosity |
A measure of the fluidity
of a liquid material. The more viscosity a material such as a sealer or
coating has, the less it flows. |
| Volatile
organic compounds (VOCs) |
Organic chemicals that
readily vaporize at normal room temperatures. Concrete coatings, sealers,
or cleaning materials that are solvent-based generally have higher VOC
contents than water-based materials. Some VOCs can be hazardous when inhaled. |
| |
| Wagner
Fineness |
The fineness of materials
such as portland cement expressed as total surface area in centimeters
per gram as determined by the Wagner turbidimeter apparatus and procedure. |
| Washout
resistance |
The ability of a concrete
mixture to remain cohesive during underwater placement. |
| Water-Cement
Ratio |
The ratio of the amount
of water, exclusive of that absorbed by the aggregates, to the amount
of cement in a concrete mix. Typically expressed as percentage of water,
by weight in pounds, to the total weight of portland cement, fly ash,
and any other cementitious material, per cubic yard, exclusive of any
aggregates. |
| Water
demand |
The amount of water required
to make a concrete mixture workable. |
| Water
plug |
A hydraulic cement used
to fill cracks and to prevent the migration of moisture. |
| Waterproof |
A material or surface that
is impervious or unaffected by water in its liquid form.will repel water
in it's liquid form but may not necessarily be vaporproof. |
|
Water reducer |
An admixture that either
increases the slump of freshly mixed concrete without increasing water
content or maintains workability with a reduced amount of water without
affecting the strength. |
| Water
Vapor Pressure |
The pressure exerted by
water vapor. Air that contains higher amounts of water vapor exerts a
higher vapor pressure than air which has a lower amount of has a higher
water vapor pressure In concrete water vapor pressure is calculated by
the difference between the vapor pressure of the concrete and the ambient
relative humidity and temperature and in contact with the soil. that is
calculated by; based upon relative humidity and temperature. The greater
the difference between the water vapor and ambient humidity and temperature,
in degrees Fahrenheit. the greater the water vapor pressure exerted. |
| Welded
wire mesh |
A woven mesh of wire strands,
welded at each intersection, used to reinforce concrete slabs. Also called
welded wire fabric. |
| Wet
polishing |
A method for polished concrete
that uses water to cool the diamond abrasives and eliminate grinding dust.
Not as commonly used as dry polishing, because the process creates a tremendous
amount of slurry (a soupy mixture of water and cement dust) that must
be collected and disposed of. |
| Wetting
Agent |
A substance capable of
lowering the surface tension of liquids, facilitating the wetting of solid
surfaces and permitting the penetration of liquids into the capillaries. |
|
White cement |
A portland cement with
a low iron content that hydrates to a white paste. Often used in integrally
colored concrete to produce pure, bright color tones, especially pastels. |
| Workability |
The ease with which concrete
or other cementitious materials can be mixed, placed, and finished. |
| Working
time |
The amount of time available
for placing and finishing a cement-based material before it begins to
set. Often depends on the ambient temperature and substrate temperature. |
| |
| Xylene |
A common solvent. Used
as a carrier for solvent based sealers. High in odor and flammability.
|
| |
| Yield |
The amount of concrete
produced by a given combination of materials, the total weight of ingredients
divided by the unit weight of the freshly mixed concrete; also, The cubic
test of concrete produced per sack of cement; also, the number of product
units, such as block, produced per batch of concrete or sack of cement. |
| |
| Zero-Slump
Concrete |
Concrete of stiff or extremely
dry consistency showing no measurable slump after removal of the slump
cone. See also Slump and No-Slump Concrete. |
