Abrasive: (1) A material used for
wearing away a surface by rubbing; (2) A fine, granulated material used
for blast cleaning. Abrasive particles of controlled mesh sizes are propelled
by compressed air, water, or centrifugal force to clean and roughen a surface.
Blast cleaning abrasives often are simply referred to as metallic or
non-metallic and as shot- or grit-like.
Abrasive Blast
Cleaning: A
surface preparation method that uses an abrasive propelled by air pressure,
centrifugal force, or water pressure to clean and usually profile a surface.
Stand-off distance, angle of attack, and dwell time are the three most
important variables under the control of an operator that can affect the
quality and effectiveness of the blast cleaning.
Acid Etching: A method of preparing concrete
floors for coating. An acid etching solution may be made of diluted
hydrochloric acid (5 to 10 percent), diluted phosphoric acid (20 to 25
percent), or, often for environmental reasons, citric acid. These and other
acid solutions can clean and remove dirt and other impurities from the concrete
as well as provide a surface texture to improve the adhesion of the coating.
Residual acid salts formed must be rinsed from the concrete surface before
coating application.
Adhesion Test,
Tensile (Pull-Off): The method for testing the greatest perpendicular force which an area
of coating can withstand before: (1) detaching from the surface (adhesion) or
(2) fracturing within a layer of coating or substrate (cohesion). The method
can also be used to determine whether a coating will remain intact at a
particular applied tensile force. This standard test method is defined in ASTM
D 4541.
Aliphatic
Polyurethane:
These coatings offer excellent resistance to ultraviolet light.
Ambient Conditions: The weather conditions including
air temperature, relative humidity, dew point, wind velocity, and air
temperature at a specific place and time or time period. These conditions are
generally monitored on the job site.
Aromatic
Polyurethane:
These coatings offer excellent chemical and heat resistance, but yellow and
chalk in direct sunlight.
ASTM: American Society For Testing And
Materials
ASTM Standard: A document (specification, test
method, guide, practice, etc.) developed and established by the consensus
principals of ASTM, a not-for-profit organization that develops standards for
products, materials, systems, and services.
Blushing: Film defect which appears as a
milky opalescence as the film dries. It is generally caused by rapid
evaporation, moisture, or incompatibility. This can affect adhesion of any
subsequent coat if not properly removed.
Broadcast: To hand toss a decorative
aggregate, or other dry material in a uniform layer over fresh coatings to add
color or traction.
Bug Holes: Small regular or irregular
cavities, usually not exceeding 15 mm in diameter, resulting from entrapment or
air bubbles in the surface of formed concrete during placement and compaction.
Calcium Chloride
Vapor Emission Test: An ASTM test used to measure the volume of moisture vapor released
from a concrete substrate over time (typically 24 hours). Too much moisture
emitted from a slab can affect the performance and bonding of overlays, coatings,
and sealers. Moisture vapor test kits are available that include small
containers of preweighed, unhydrated calcium chloride.
Cementitious: A material containing Portland
Cement as one of its components or having cement-like properties.
Coating System: A protective film consisting of
one or more coats, applied in a predetermined order by prescribed methods. A
coating system description in a specification may include surface preparation
and quality control requirements.
Compressive
Strength: The
maximum compressive stress concrete or cementitious overlay materials are
capable of sustaining, expressed as pounds per square inch (psi).
Construction
Joints:
Joints formed when one slab pour ends and another begins and are usually found
at column lines.
Control Joints: Saw-cut joints designed to
control slab cracking and minimize random cracking.
Coverage Rate: The area that a specified volume
of coating will cover to a specified thickness upon drying.
Crack Chasing: Routing out cracks in concrete
with a saw or angle grinder before filling with a repair material.
Curing: The process by which a coating
changes from a liquid state into a dry, stable, solid protective film.
Curing Agent: An additive component, sometime
called a hardener that helps a coating film or concrete cure by chemical
reaction.
Curing Compound: A liquid that, when applied to
the surface of newly placed concrete, forms a membrane on the concrete or
penetrates the concrete to retard the evaporation of water.
Delaminate: A separation of a coating or
topping from a substrate or the layers of a coating from each other due to poor
adhesion.
Densifier: A penetrating liquid chemical
hardener applied to concrete to help solidify and densify the surface and
provide extra protection from water penetration and staining. Often recommended
for polished concrete, because hard concrete produces a better polish.
Dew Point: The temperature at which air
becomes saturated with water, that is, when the air is at 100 percent relative
humidity. Below this temperature, moisture will condense and produce dew or
fog. As air is cooled, the amount of water vapor it can hold decreases.
Expressed another way, the point where the actual water vapor pressure becomes
equal to the saturation water vapor pressure; any further cooling beyond this
point normally results in the condensation of moisture.
Diamond Grind: a method of preparing a concrete
surface using a planetary head diamond grinder fitted with diamond-segmented
abrasive discs. Often it is used after shot blasting to smooth out shot blast
lines and to complete surface preparation.
Efflorescence: A crystalline deposit of salts
(usually white in color) that forms on the concrete surface when soluble
calcium hydroxides leach from the concrete and combine with carbon dioxide in
the atmosphere. On colored concrete, especially darker tones, these white
deposits can be particularly unsightly.
Epoxy: Flooring epoxies consist of two
parts, a resin and a hardener. Good quality epoxies are 100% solids, no
solvents. Epoxies typically are used as a primer and build coat. They are also
used as the binder resin in most resurfacer systems.
Expansion Joint: an isolation joint intended to
allow independent movement between adjoining concrete pads.
Fibers: Tiny filaments made of
polypropylene, polyolefin, nylon, polyethylene, polyester, or acrylic used
alone or in conjunction with rebar or welded wire mesh to reinforce concrete.
Film Thickness: the depth of the film when wet
(wet film thickness) and the final depth when dry (dry film thickness) usually
expressed in mils (0.001 inch).
Fish Eyes: Imperfections in the concrete
coating caused by contaminants such as oil and silicone.
HEPA: Commonly used abbreviation for
high efficiency particulate air filters; encompasses specifications and testing
requirements set for air filters by the U.S. Department of Energy.
High Build Coating: A protective or decorative
coating that produces a thick film (usually greater than 10 mils) in a single
coat.
IAQ: Stands for indoor air quality
Integral Color: A coloring agent premixed into
fresh cementitious toppings before application.
Green Concrete: Concrete that has set but not
appreciably hardened.
Laitance: A thin layer of fine, loosely
bonded particles on a concrete surface caused by an upward movement of water.
Laitance must be removed before application of a coating.
LEED: Acronym for Leadership in Energy
and Environmental Design. A Green Building Rating System® created
and implemented by the U.S. Green Building Council.
Moisture Vapor
Emission Rate:
Measurement of moisture vapor movement through a concrete slab. ASTM F 1869
describes how this is accomplished by absorbing moisture on anhydrous calcium
chloride.
Mil: A measurement equal to 1/1,000
(0.001) inch. Commonly used to denote coating thickness.
Moisture Vapor
Transmission Rate: Rate of movement of moisture vapor through a membrane.
Orange Peel Finish: Coatings can be applied with a
textured, orange peel finish to provide some slip resistance.
Overlay: A bonded layer of material,
ranging from ¼ inch to 1 inch or more in thickness, placed on existing concrete
surfaces to level or restore.
pH Neutral: Chemicals that are neither acidic
nor alkaline are pH neutral. On the pH scale, low pH corresponds to high
hydrogen ion concentration, and high pH corresponds to low hydrogen ion
concentration. A substance that when added to water increases the concentration
of hydrogen ions (lowers the pH) is called an acid. A substance that reduces
the concentration of hydrogen ions (raises the pH) is called a base.
Primer: The first coat of material
applied to a concrete surface to improve bonding or adherence of subsequent
coats.
Profile: The act of preparing a concrete
surface to achieve the necessary degree of roughness.
Sacrificial coating: A final floor finish designed to
protect the sealer or topcoat from wear.
Sawcutting: Using a concrete saw with
abrasive blades or disks to cut joints into hardened concrete.
Scarify: A method of mechanically
preparing concrete for coating or removing existing coatings. Uses rotary
impact cutters held at a right angle to the surface.
Scratch Coat: A base coat used to improve the
rigidity and/or bonding of subsequent topcoats.
Seeding: Broadcasting aggregates on the
surface of freshly placed concrete floor toppings
Shore Hardness: the relative hardness of a
material is measured by using "duromete gauge," the most common being
a Shore durometer gauge. There is a needle at the bottom of the gauge, which is
pressed against the material to be tested. The Shore A gauge has a dull needle
used to measure the hardness of rubberlike materials.
Shot blasting: An abrasive blasting method using
round iron shot to clean and profile concrete surfaces.
Spalling: The chipping or fragmenting of a
surface or surface coating or joint edge caused for example by hard wheel
impact and/or the loads imposed.
Substrate: An existing concrete surface that
receive an overly, decorative or protective coating, repair procedure, or other
resurfacing treatment.
Surface Profile: The roughened surface that
results from abrasive blast cleaning. Surface profile is simply the texture of
the cleaned surface.
Tack: The stickiness or adhesiveness of
a material.
UV Stable Coatings: Resist yellowing from ultra-violet light.
Vapor Barrier: Traditionally specified to
minimize moisture inflow through concrete that is in contact with water or
water vapor from a high water table. Vapor barriers are used to protect floor
coverings that might be damaged from moisture moving upward through the
concrete slab. Polyethylene sheeting is the most common vapor barrier material.
A 4- to 6-mil thick polyethylene sheet is typically placed on a compacted
subgrade or on a sand layer spread over the subgrade. Thicker, stronger
sheeting materials resist punctures better during construction.
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/gasses that are released from certain solids or liquids.
Concrete coatings, sealers, or cleaning materials that are solvent-based
generally have higher VOC contents than water-based materials. Reducing VOC's
reduces the potential ill-effects they may have on occupants in indoor spaces.