AC Tech concrete sealers
are coatings applied to concrete to protect it from corrosion.
They either block the pores in the concrete to reduce absorption
of water and salts or form an impermeable layer which prevents
such materials from passing. Get your ACT® together!
Extensive on-going research
from AC Tech and concrete authorities in North America –
American Concrete Institute, Portland Cement Association,
National Ready Mix Concrete Association - confirm that almost
all damage to concrete is attributable to moisture intrusion:
alkali-silica reaction (ASR), chemical intrusion, and freeze/thaw.
AC Tech has a superior research and development program
continuously in process.
For decades attempts
to protect concrete from moisture vapor
have included sealers ranging from wax to linseed oil. Today,
all high quality sealers can block surface moisture which
can transmit damaging chemicals and induce freeze/thaw damage.
There are two main sealer categories:
topical sealers (film-forming) and penetrating sealers (reactive).
Topical sealers generally provide visual enhancement as
well as topical protection. They require dry, clean surface
during application to gain adhesion. AC Tech products have
a 15 year warranty.
sealers can be applied to dry or damp surfaces and should
be properly matched with substrate porosity in order to
penetrate the surface, clot, and form a barrier. Penetrating
sealers generally do not significantly modify substrate
appearance. They are chemically reactive and bond with minerals
in cement reducing the amount of free silica available for
ASR and reduce moisture required to induce ASR. As well
as blocking surface moisture they block subterranean moisture
and can reduce efflorescence. ACT® penetrating sealers
can harden and increase the density of concrete, increasing
its strength as measured in pounds per square inch (PSI).
The Lifespan of these sealers can be nearly permanent.
major compounds are commonly used in concrete sealers
Acrylic resins form
a topical thin film membrane. Acrylics are affordable and
generally simple to apply. They are well known to increase
perceived visual enhancement and generally provide good
UV protection for colored substrates. They can make substrates
slick when wet, sometimes requiring the addition of anti-skid
materials. Despite being the softest and least lasting of
the major sealer categories, price and convenience make
acrylics a very popular choice for residential applications
such as stamped concrete and exposed aggregate.
are also topical film-forming membranes. They share many
of the same characteristics as acrylics, but the performance
levels and life span are superior and commensurately they
are more costly. Epoxy/urethane systems are frequently used
in demanding applications such as factory floors, garage
floors, and restaurants.
Silanes are the smallest
molecular compound of penetrating sealers. Generally expensive,
100% silane versions offer high standards of performance
in high-value flooring applications with substrates of limited
porosity, such as parking garages, slate, blue stone and
other valuable materials.
Silicates are another
small molecular compound frequently used for sealing substrates
of moderate porosity. They are ideal for sealing substrates
such as factory floors, retail show rooms, garage floors
and basements. When burnished, premium silicate blends such
as lithium silicates can help concrete develop a polished
appearance popular in many large format retail outlets and
home centers. Plain silicates are low in cost, and as such
are often misapplied as a sealer for porous, broom finished
substrates such as driveways. This is a poor use of the
chemistry, as the liquid disperses randomly without forming
a substantial protective moisture barrier.
Siliconates are the
largest molecular compound of truly penetrating sealers.
While relatively expensive, they are the ideal molecular
compound for sealing highly porous substrates such as driveways,
sidewalks, parking lots, stucco, foundations, concrete block,
many types of natural stone and artificial stone, and mortar.
Siliconate and organo-siliconates have also been shown to
be highly effective as curing agents for new concrete.
Siloxanes and silicones
are sometimes described as penetrating sealers. However,
neither compound is highly chemically reactive, a trait
of a true penetrating sealers. Additionally, both are large
molecular compounds which provide predominantly topical
protection. Because these materials remain predominately
at, or near, the surface the benefits are not as long lasting
as properly applied silane, silicates or siliconates. When
blended with silanes, siloxanes are an effective sealer
for vertical surfaces where surface wear is not a major
factor. Because of their slickness, silicones are generally
used in vertical applications as moisture and graffiti barriers.
Several of the above listed sealers can be used in combination.
Silanes, silicates and
siliconates, which must be applied directly to the substrate,
can be very receptive to topical coatings and can be used
first in a flooring multi-component
system, followed by acrylics or epoxy/urethane systems.
Silicates can also be
applied as a second step with siliconates as the smaller
molecules can provide additional pore closure. Siloxanes
and silicones are too topical in nature to be reliably used
on conjunction with topical coatings.
In building construction,
a structure needs waterproofing since concrete itself will
not be watertight on its own (but note concrete is easily
waterproofed with additives). The conventional system of
waterproofing involves 'coatings'. This relies on the application
of one or more layers applications (available in various
materials: e.g., bitumen, silicate, etc.) that act as a
vapor barrier between the water and the building structure,
preventing the passage of water.
Over the past two decades,
the construction industry has had technological advances
in waterproofing materials, including integral waterproofing
systems as well as more advanced engineered
Integral systems work
within the matrix of a concrete structure, giving the concrete
itself a waterproof quality. There are two main types of
integral waterproofing systems: the hydrophilic and the
hydrophobic systems. A hydrophilic system typically uses
a crystallization technology
that replaces the water in the concrete with insoluble crystals.
Various brands available in the market claim similar properties,
but not all can react with a wide range of cement hydration
by-products, and thus require caution. Hydrophobic systems
use fatty acids to block pores within the concrete, preventing
New membrane materials
seek to overcome shortcomings in older technologies. Generally,
new technology in waterproofing material relies on polymer
based materials that are extremely adhesive to create a
seamless barrier around the outside of a structure (positive
side) or inside a structure (negative
once completed becomes very difficult since the water pressure
is from the external side (from outside coming inside),
the difficulty arises when a product cannot withstand hydrostatic
pressure from within the substrate and therefore fails.
Water may enter a basement through various means including
through joints, walls, or floors. Various basement waterproofing
systems address these problems. There are many systems available
of varying cost, effectiveness, and installation invasiveness.
may be done internally and externally. Because basement
foundations can be brick, block, concrete, and even wood,
it is important to pick the right waterproofing system for
the right foundation. One effective way to waterproof cracks
in poured concrete walls is by epoxy injection.
Benefits include that
they move with the structure and do not absorb water.
Bitumen is a hydrocarbon and is
created naturally from crude oil.The
products have an extremely long life span. The
fumes given off during installation are not harmful to
human health and there is low noise pollution during application.
products protect insulation and can reflect harmful
sun rays. New products also
contain photovoltaic cells that can produce solar energy.Bitumen
is not water soluble, non-biodegradable, not classified
as carcinogenic and does not release harmful toxins.
ACT cementitious waterproofing
products are ECC, engineered cementitious composites.
This allows ACT cementitious
waterproofing products to deform without catastrophic
ECC have a variety of unique properties,
including tensile properties superior to other fiber-reinforced
composites, ease of processing on par with conventional
cement, the use of only a small volume fraction of fibers
(~ 2 %), tight crack width, and a lack of anisotropically
weak planes. These properties are due largely to the interaction
between the fibers and cementing matrix, which can be
custom-tailored through micromechanics design. Essentially,
the fibers create many microcracks with a very specific
width, rather than a few very large cracks (as in conventional
concrete.) This allows ECC to deform without catastrophic
Vapor Barriers: Nuisance
The subject of vapor barriers or
retarders beneath concrete slabs on grade has long been
controversial. Some justifiably argue that slabs placed
in direct contact with a vapor barrier or retarder are
more susceptible to curling and other slab problems than
those cast on a granular base. They consider a vapor barrier
or retarder a downright nuisance.
A brief description
of alternative methods for dealing with slab moisture problems
by Peter A. Craig. Moisture-related problems with floor
coverings and coatings applied over concrete slabs have
become a serious and costly issue for designers, constructors,
manufacturers, installers, and owners. Problems are being
experienced on both new and renovation projects.
The long-awaited day has come,
the project is complete, and everyone involved is eager
to show off the new look of the facility. But wait a minute.
Something is terribly wrong. Adhesive is bleeding through
joints between the floor tiles, and there are bubbles
in the sheet goods and epoxy flooring. Worse yet, there
is a noticeable odor in the air. Sabotage? No, unfortunately
what is occurring on this project has become all too common
across the country. Such problems are being caused by
moisture and moisture-induced high pH levels beneath flooring
& pH Stabilization System Application
Site Review (JD Technical can schedule an on-site visit
JD Technical Group Inc.
will recommend AC Tech products based on your project's
unique requirements for warranties to remain valid.
A key to getting good
results with epoxy coatings is surface
preparation. Overkill is much better. You should clean/degrease
followed by at least one thorough clean water rinse. Allow
the surface to dry completely (at least 12 hours) before
coating. Work quickly, since the coating has a limited life
span once the two components are mixed together.
What type of
moisture mitigation strategies are in place?
How will you
waterproof the basement areas?
How do you seal
between basement floor and foundation walls?
How were concrete
slabs treated to protect floor coverings? Tile, wood, carpet?
Do you normally
seal and waterproof all windows, exterior doors and other
Are the steps
taken LEED acknowledged?
There are always instances
when a vapor barrier is going to make a tremendous
difference in the moisture content, the damage from
mildew and mold, or humidity in a building. If you
are not sure of which waterproofing products should
be used, call 267-221-4483, email
or fill out our contact
F 1869-10, “Standard Test Method for Measuring Moisture
Vapor Emission Rate of Concrete Subfloor Using Anhydrous
Calcium Chloride,” ASTM International, West Conshohocken,
PA, 2004, 3 pp.
F 2170-09, “Standard Test Method for Determining Relative
Humidity in Concrete Floor Slabs Using In-Situ Probes,”
ASTM International, West Conshohocken, PA, 2002, 5 pp.
Manufacturers requiring RH testing (click
F 710-08, “Standard Practice for Preparing Concrete
Floors to Receive Resilient Flooring,” ASTM International,
West Conshohocken, PA, 2005, 6 pp.
These definitions are intended to promote general familiarity
with common terms of the concrete industry.
Admixture: a natural or manufactured chemical
which is added to concrete before, or during, its mixing. Admixtures
are often deployed to add special properties to concrete.
Ambient RH: the relative humidity surrounding
a concrete slab. The RH of air in a room or in the open qualifies
ASTM: American Society for Testing and Materials:
a global body which develops voluntary consensus standards in
Calcium Chloride testing: a moisture content
assessment procedure which measures the water evaporation rate
at the surface of concrete.
Cement: a substance which binds other materials
together, such as aggregate and water, to form concrete.
Concrete: a composite mixture of cement, aggregate
Concrete moisture meter: a measurement device
which assesses the relative humidity level of concrete.
Curing: the process by which concrete hardens
due to the chemical process of hydration.
Equilibration: the process by which the relative
humidity of a building material, such as concrete, is balanced
with the RH of its surrounding environment; also used to refer
to the process of an in situ probe reaching similar or balanced
conditions (temperature, moisture levels, etc) to the surrounding
Hydrostatic pressure: units of pressure which
are created by a liquid when it is at rest.
In Situ probe: a sensor which must be embedded
in a concrete slab (typically by drilling a hole into the slab
and installing a sensor within a sleeve) in order to assess
the slab's moisture content (MC).
Leapfrogging: the act of moving concrete RH
probes to several test places in a concrete slab without allowing
sufficient time for the probes to equilibrate.
Moisture content (MC): the term used to describe
the amount of water vapor within a concrete slab.
Multi-use probe: a relative humidity(RH) measurement
device which contains a sensor and a separate plastic, cylindrical
sleeve. Builders place the sleeve inside a hole drilled in concrete,
then insert the sensor into to cylinder to measure concrete
RH. Â Multi-use probes can be re-calibrated in order to be re-used
on another job site.
MVER: Moisture Vapor Emissions Rate which
indicates the rate of moisture evaporation from the surface
of concrete. MVER is a result of Calcium Chloride (CaCl) testing.
Portland cement: a widely-used form of cement
which hardens in contact with water to produce a water-resistant
Power troweling: the process of smoothing
a concrete slab surface using motorized equipment.
Relative humidity (RH): the term used to describe
the ratio of water vapor in the combined mix of air and water;
relative humidity is also used to express the ratio of moisture
content in concrete.
RH testing: a procedure which determines the
amount of water vapor (or relative humidity) in concrete.
Service conditions: the point at which a building's
concrete slab is fully enclosed and the heating, ventilation
and air conditioning (HVAC) systems are up and running.
Single-use probe: a relative humidity(RH)
measurement device designed for use on a single job site. A
single-use probe is typically skim-coated into the slab once
testing is complete.
Slab temperature: the temperature of concrete
below the surface of the slab.
Substrate: a structural reinforcement beneath
a concrete slab; or, the concrete slab or subsurface directly
beneath a flooring finish.
Vapor barrier: a building material, such as
plastic or foil sheeting, which serve to slow (or retard) moistures
permeation from external sources into a concrete slab.