This document discusses concrete permeability and durability. It defines concrete and its composition, noting that concrete is made up of cement paste and aggregates. The cement paste binds the aggregates but is also porous, allowing water and chemicals to pass through. Several degradation mechanisms are described, all of which involve the penetration of water or other substances into the concrete. The document emphasizes that permeability determines a concrete's vulnerability, and that reducing permeability is key to improving durability. It describes different transport mechanisms by which substances can move through concrete, including diffusion, capillary action, and permeation.

1. Integral Crystalline
Waterproofing Technology
Alireza Biparva, B.Sc, M.A.Sc
Cementitious Materials Specialist
&
Kevin Yuers, B.A.
VP, Technical Services
Kryton International Inc.

2. Important Notice: Images and content provided in this presentation
are owned by Kryton International Inc. Any content used by you
must be properly attributed to Kryton International Inc. along with a
hyperlink to this presentation on SlideShare. For more information,
e-mail webpr@kryton.net

3. Table of Contents
1.Concrete and Durability
2.Permeability
3.Waterproofing
4.Crystalline Technology

4. CONCRETE
DURABILITY

5. Concrete Durability
Concrete Basics
Concrete has been widely used as a major construction material for centuries.
Its low cost, versatility, unique engineering properties, and the availability of the
constituent materials makes its utilization more attractive than other
construction materials.
michaelscomments.wordpress.com/.../
A key advantage to the use of concrete is that it can be molded or formed into
virtually any shape when newly mixed, and is strong and durable when
hardened. These qualities explain why concrete can be used to build
skyscrapers, bridges, sidewalks, superhighways, houses, and dams.

6. Concrete Durability
Concrete Composition
Concrete is a heterogeneous composite of coarse and fine aggregate
particles held together by cement paste. This paste is the glue made from
cement and water that hardens due to a chemical reaction called hydration. It
binds the aggregate particles into a solid, rock mass material.
Cement paste ordinarily constitutes
about 25 to 40 % of the total
volume of concrete. The paste is
porous and is prone to water
movement through the pores and
microcracks present in the paste.

7. Concrete Durability
Concrete Composition cont d
Since aggregates make up about 60 to 75 % of the total volume of concrete,
their selection is important. Aggregates should consist of particles with
adequate strength and resistance to the exposure conditions they will face.
They should not contain materials that will cause deterioration of the concrete.
A continuous gradation of aggregate particle sizes is desirable for efficient use
of the paste.
The quality of the concrete depends upon the quality of the paste and the
quality of the aggregate, as well as the bond between the two. In properly
made concrete, each and every particle of aggregate is completely coated with
paste and all of the spaces between the aggregate particles are completely
filled with paste.

8. Concrete Durability
Concrete Admixtures
Concrete admixtures are ingredients other than water, aggregates, and
hydraulic cement that are added to the concrete mix to modify its properties;
they may be extracted from organic materials or they may be artificially
manufactured.
www.concretethinker.com/Papers.aspx?DocId=2
www.cement.org/tech/faq_spalling.asp www.cmaxgrc.com/pp_cruved.html
Admixtures offer various beneficial effects to concrete, including improved
quality, modification of setting times, enhanced resistance to chemicals or frost,
control of strength development, improved workability, reduced permeability,
etc. The three main types of concrete admixtures are: chemical admixtures;
mineral admixtures; and miscellaneous admixtures.

9. Concrete Durability
Admixtures
Chemical Admixtures
Chemical admixtures are used to economically modify the concrete to attain
certain properties such as reduction of water or cement content, entrainment of
air, plasticization of fresh concrete, and controlled setting time. In medieval
times, milk and blood were considered admixtures because of their sublimation
effect on the concrete.
The basic categories of chemical admixtures
outlined in ASTM C494 are:
Type A- Water-reducing
Type B- Retarding
Type C- Accelerating
Type D- Water-reducing and retarding
Type E- Water-reducing and accelerating
Type F- High range water-reducing
Type G- High range water-reducing and retarding www.cement.org/tech/cct_admixtures_AEA.asp

10. Concrete Durability
Admixtures
Mineral Admixtures
Mineral admixtures are supplementary cementitious materials (SCM) such as
fly ash, silica fume, and ground granulated blast-furnace slag (GGBFS) are
often added to concrete to make mixtures more economical, less permeable, or
to improve other concrete properties.
Mineral admixtures are normally residual materials from different industrial
processes; they contribute to the properties of hardened concrete through
hydraulic or pozzolanic activity.
Hydraulic activity is how hydraulic cements
hydrate, set, and harden when mixed with
water. GGBFS and some Class C fly ashes
are SCMs with hydraulic properties. Hydration
of systems containing hydraulic SCMs is
generally slower than mixtures with only
Portland cement. www.cement.org/basics/concretebasics_suppleme...

11. Concrete Durability
Admixtures Mineral Admixtures
Pozzolanic Activity
Pozzolana are siliceous materials which themselves possess little or no
cementitious value but will react chemically with byproducts of cement
hydration, such as calcium hydroxide. During the hydration reaction
between Portland cement and water, a cementitious gel (calcium silicate
hydrate) and lime (calcium hydroxide) are formed.
PCA R&D Serial No. 3005 page 91
Pozzolanic materials react with this lime in the presence of moisture to form
additional cementitious gel. This reaction leads to a reduction in the
permeability of the concrete and an increase in its strength.

12. Concrete Durability
Admixtures
Miscellaneous Admixtures
Specialized admixtures that are not considered chemical admixtures or
mineral admixtures are categorized as miscellaneous admixtures.
Miscellaneous admixtures can provide unique properties to the concrete and
come in many forms. They are comprised of organics, inorganics, synthetics or
a combination. Some unique properties that can be achieved are impact
resistance, dampproofing, waterproofing, coloring, and increased tensile
strength.
www.eftfibers.com/images/slide.gif

13. Concrete Durability
Durability
Concrete durability has been defined as its resistance to degradation
processes such as weathering, chemical attack, abrasion, impact and physical
strains.
Built in 1755 Built in 1970
web.mit.edu/jsf/2004/pantheon.html asp.usatoday.com/.../utils/idmap/13740316.story
Ultimately, the durability and life expectancy of the concrete is dependent on
the choice and proportioning of ingredients, the quality of workmanship during
placing and the conduct of proper curing practices.

14. Concrete Durability
Durability cont d
A concrete mixture design is only an intended proportion of ingredients. A
good mix design will produce good laboratory results, but in order to achieve
durable concrete in the field, we need proper placement and curing as well.
If any one of these three are missing, the durability of the concrete will be
compromised.

15. Concrete Durability
Durability cont d
In most instances, deterioration in concrete is due to a lack of adequate
durability, rather than deficient strength. Concrete structures can become
unserviceable due to gradual weakening arising from concrete deterioration
and steel corrosion.
à à à
www.corrosion-club.com/concrete1.htm
Hence, due to its economic and technical importance, reducing concrete
deterioration by increasing its durability has become a challenging problem
facing the industry. The economic loss due to deterioration of concrete and steel
corrosion may constitute up to several percentage points of a country s gross
national product.

16. Concrete Durability
Degradation Mechanisms
Concrete deterioration can be due to adverse mechanical, physical, or chemical
causes. It is often the case where one or more deteriorative mechanisms are at
work by the time a problem is identified. In fact, in terms of deterioration of
concrete due to physical or chemical causes, the mobility of fluids or gases
through the concrete are nearly always involved.
The overall susceptibility or penetrability of a concrete structure, especially
when compounded by additional environmental or exposure challenges, is the
key to its ultimate serviceability and durability. Important degradation
mechanisms in concrete structures include the following:
Corrosion of reinforcing steel
Alkali-aggregate reactions
Carbonation
Sulfate attack
Freezing and thawing

17. Concrete Durability
Degradation Mechanisms
Corrosion of Reinforcing Steel
Concrete is very strong when loaded under compression, but when stressed
under tension or torsion it is not very strong at all. Hence, it is common practice
to reinforce concrete with steel for improved mechanical properties.
The principal cause of degradation in steel reinforced concrete structures is
corrosion damage to the rebar embedded in the concrete.
The two most common causes of
reinforcement corrosion are:
1. Localized breakdown of the passive film
on the steel by chloride ions, and
2. General breakdown of the passive film by
neutralization of the concrete,
predominantly by reaction with
atmospheric carbon dioxide
www.buildingrectification.com.au/pages/concre...

18. Concrete Durability
Degradation Mechanisms -Corrosion of reinforcing steel
Passive Layer
Steel embedded in hydrating cement paste forms a passive oxide layer
which strongly adheres to the steel surface and gives it complete protection
from corrosion. This is why rebar does not corrode inside the concrete even
though it is wet. Maintenance of this passive layer is conditional on an
adequately high pH of pore water in contact with the passivating layer.
www.cement.org/tech/cct_dur_corrosion.asp
A process called carbonation reduces the pH of the pore solution to as low as
8.5. At this level, the passive film on the steel is no longer stable and corrosion
begins.

19. Concrete Durability
Degradation Mechanisms
Carbonation
Carbonation of concrete is a process by which carbon dioxide in the air,
combined with moisture, reacts with hydrated cement to form carbonates.
The rate of carbonation is significantly
increased in concrete that has a high
permeability due to porous paste, porous
aggregates, high water to cementing
materials ratio, low cement content,
short curing period, or poor
consolidation. Carbonation does not
actually harm the concrete directly.
However, by lowering the pH and thus
the passive layer protection of the www.dundee.ac.uk/.../Carbonation%20Project.htm
embedded steel, expansive corrosion is
soon to follow.

20. Concrete Durability
Degradation Mechanisms
Corrosion-Failure
Corrosion of reinforcing steel will eventually lead to the failure of the concrete.
Steel expands as it corrodes. The resulting stress will generally fracture the
concrete cover. Cracks provide a path for water to carry oxygen and corrosive
chemicals to the steel. The process become a death spiral for the concrete
structure.
Water & Chemical
Ingress
Steel
Cracking
Corrosion
Expansion Stress

21. Concrete Durability
Degradation Mechanisms
Alkali-Aggregate Reactions
Alkali-aggregate reactivity (AAR) is a reaction between the active mineral
constituents of some aggregates and the sodium and potassium alkali
hydroxides in the concrete.
Alkali-aggregate reactivity occurs in two forms
i. alkali-silica reaction and
ii. alkali-carbonate reaction
Both alkali-silica and alkali- carbonate reactions
result in swelling of the concrete. The amount of
swelling or expansion depends on the reactivity
of the aggregates, the alkalinity of the cement
solution, and the ambient moisture conditions of
the structure. Indications of the presence of
deleterious alkali-aggregate reactivity may be in
the form of a network of cracks (map cracking),
closed or spalling joints, or displacement of
different portions of a structure.

22. Concrete Durability
Degradation Mechanisms
Sulfate Attack
Sulfates can attack concrete by reacting with hydrated compounds in the
hardened cement paste. These expansive reactions can induce sufficient
pressure to disrupt the cement paste, resulting in disintegration of the
concrete (loss of paste cohesion and strength).
Design and control of Concrete Mixture book p16
Sulfate attack on concrete is a relatively rare but complex damage
phenomenon caused by exposure of concrete products or structures to an
excessive amount of sulfate usually in sulfate containing soils.

23. Concrete Durability
Degradation Mechanisms
Freezing & Thawing Damage
When water freezes to ice, it occupies 9% more volume than when it was
liquid. If this water happens to be filling the pores of concrete, the results can
be very damaging. Concrete that is exposed to repeated freezing and
thawing cycles when in a saturated condition will quickly deteriorate if not
designed properly.
To protect concrete from freezing
and thawing damage, an air-
entraining admixture is added,
which creates millions of tiny,
closely spaced air bubbles in the
hardened concrete. The air bubbles
relieve the pressure build-up
caused by ice formation by acting
as tiny expansion chambers.
www.concrete-experts.com/pages/ft.htm

24. Concrete Durability
Degradation Mechanisms
Water Penetration is the Root Cause
Note that in every case, it is the presence of moisture or water within the
concrete that is at the root of each destructive process.
www.concrete-experts.com/pages/ft.htm

25. PERMEABILITY

26. Permeability
Durability and Permeability
It is well known that permeability determines the vulnerability of concrete to
external agencies, and in order to be durable, concrete must be relatively
impervious. Concrete durability depends largely on the ease or difficulty with
which gases or fluids can migrate through the hardened concrete mass. As
the permeation of concrete decreases, its durability performance, in terms of
physicochemical degradation, increases.
The durability of concrete is fundamentally based on the
permeability of concrete.
Permeation controls the ingress of moisture, ionic, and gaseous species into
concrete. Given that most deleterious agents are transported through water
and water itself is one of the deleterious agents, the durability of any concrete
depends largely on the permeability of concrete. So evaluation of concrete
permeability can be used to indirectly estimate its durability.

27. Permeability
Transport Mechanisms
The ingress of deleterious substances into concrete takes place through the pore
system in the cement matrix or through micro-cracks. There are several factors
that determine the rate at which a substance is able to flow through the concrete
matrix including porosity, pore size distribution, pore connectivity, pressure
differential, and the degree of pore saturation.
The principal ways through which an aggressive substance may transport
through the concrete matrix are diffusion, capillary action , and permeation. The
transport of aggressive substances into the concrete matrix may not be due to
any single mechanism, but several mechanisms acting simultaneously.
Diffusion
Capillary Action
Permeation

28. Permeability
Transport Mechanisms
Diffusion & Capillary Action
Diffusion is the process by which a
fluid can pass through concrete under
the action of a concentration gradient. It
is defined as the transfer of mass by
random motion of free molecules or
ions in the pore solution resulting in a
net flow from regions of higher
concentration to regions of lower
concentration of the diffusing
substance .
Capillary action transports liquids through a porous solid by way of surface
tension acting in the capillary pores. Capillary action is affected by the
characteristics of both the liquid and the porous medium. The characteristics of
the liquid that influence capillary action are viscosity, density, and surface
tension. The influencing characteristics of the solid include pore structure
(radius, tortuosity, and capillary continuity) and surface energy.

29. Permeability
Transport Mechanisms
Permeation
Permeability can be defined as the ease with which a fluid can flow through
a solid. The flow through a media is caused by a pressure differential. The
coefficient of permeability is the characteristic describing the permeation of
fluids through a porous material due to a pressure head.
There are a variety of pores and
voids in concrete which can have
direct effects on the permeability
of concrete. Pores and voids in
concrete can be broadly classified
as gel pores, capillary pores, and
paste-aggregate interfacial zones.

30. Permeability
Transport Mechanisms - Permeation
Gel Porosity
The architecture of the porous body governs the transport properties. The solid
phase is composed of hydration products and unhydrated cement grains. The
hydration products are called the gel. The gel contains approximately 28 %
porosity and are the smallest interconnected interstitial spaces.
Gel Porosity
These gel pores are 2-3 nm in nominal diameter only an order of magnitude
larger than a molecule of water, so gel water is tightly bound. Gel pores
contribute to the possibilities of fluid transport across cement paste but in a very
limited way and cannot play a big role in the permeability of concrete.

31. Permeability
Transport Mechanisms - Permeation
Capillary Porosity
Capillary pores represent the portion of volume within the cement paste not filled
by the products of hydration. The size, distribution and number of capillary pores
is determined by the initial ratio of water to cementitious materials and the
degree of hydration. The size of capillary pores can range from 0.01 pm to 5 pm.
Interconnected capillary pores form as bleed water escapes from the setting
concrete.
Capillary Porosity
As hydration progresses, the capillary pores become segmented. When the
capillary pores are no longer percolated, the permeability decreases
dramatically and the paste is called depercolated paste. Following hydration,
capillary pores may become discontinuous if w/cm ratios are low enough.

32. Permeability
Transport Mechanisms -Permeation
Interfacial Zone Porosity
Theoretically, concrete can be described as a
two-phase material: aggregate and cement
paste. Consequently, adding low-permeable
aggregates to cement paste should reduce the
concrete s permeability by interrupting capillary
pore continuity in the cement paste matrix.
However, test results indicate that the opposite
is true; a considerable increase in permeability
occurs when aggregates are added to a paste
or mortar.
In fact, concrete is a three-phase material:
aggregate, cement paste, and interfacial
transition zone (ITZ). The ITZ is the area of
contact between the cement paste and the
surface of the aggregates.

33. Permeability
Transport Mechanisms -Permeation
Interfacial Zone Porosity
The porosity of the paste-aggregate
interfacial zone is usually much higher
than the rest of the paste matrix. The
different pore structure of ITZ around
the aggregate is due to bleeding, the
higher local w/c ratio, and the influence
of aggregate surface. Also, the particle
size of the aggregate plays an important
role in the permeability of concrete; the
larger the aggregate size, the greater
the permeability.
The ITZ is normally of the order of 50 nm in thickness and can occupy 30-50%
of the total volume of the cement paste in concrete. In comparison to the bulk
hydrated cement paste, the paste-aggregate interfacial zone is weaker, carries
leachable compounds, and can be the least resistant path for migrating
moisture and other harmful substances.

34. Permeability
Transport Mechanisms -Permeation
Micro Cracks
The amount of micro cracks depends on numerous
parameters, including aggregate size and grading, cement
content, w/c ratio, degree of consolidation of fresh concrete,
curing conditions, environmental humidity, and thermal
history of concrete. During the initial stages of hydration, the
transition zone is weak and cracking may occur due to
strains between the cement paste and the aggregate caused
by drying shrinkage, thermal strains, and externally applied
loads.
Cracks in concrete generally interconnect flow paths and
increase concrete permeability. The increase in concrete
permeability due to crack progression allows more water or
aggressive chemical ions to penetrate into the concrete,
facilitating further deterioration. Such a chain reaction of
deterioration-cracking, more permeable concrete, further
deterioration may eventually result in destructive
deterioration of the concrete structure.

35. Permeability
Porosity vs. Permeability
Micro cracks in the cement paste
matrix may contribute significantly to
the permeability. In general,
connectivity of the pore system is a
prerequisite for concrete permeability.
Cracks in concrete generally
interconnect flow paths and increase
concrete permeability. A highly porous
material might perform well as long as High porosity, high permeability
the pores are not interconnected.
High porosity, low permeability Low porosity, high permeability

36. Permeability
Water Permeability
Water is the most significant fluid that
flows through concrete. In porous
materials, water permeability usually
determines the rate of deterioration.
Water can be directly involved in
physical processes leading to
degradation, especially during the
repeated freezing and thawing cycles.
In addition, water also serves as the
carrying agent for soluble aggressive
ions that can be the source of chemical www.tececo.com/technical.porecocrete.php?print
degradation.
Low porosity / permeability / penetrability of concrete to moisture is the first line
of defense against frost damage, acid attack, sulfate attack, corrosion of steel
embedment and reinforcements, carbonation, alkali-aggregate reaction, and
efflorescence and other concrete ailments.

37. WATERPROOFING

38. Waterproofing
Dampproofing vs. Waterproofing
Dampproofing and waterproofing products are applied as either a surface
coating or admixture. Most dampproofing products that get applied to the
surface are coatings and form a physical barrier against water. Dampproofing
admixtures are typically hydrophobic (water-repellent) materials and function by
way of surface tension. Dampproofing products are designed to prevent water
from absorbing and wicking through concrete that may be damp or wet.
Dampproofing products will not resist water under pressure.
For structures exposed to water under
hydrostatic pressure, waterproofing is
required. Waterproofing materials,
whether surface applied or admixtures,
form a strong physical barrier to water and
will prevent water from entering the
concrete even under a significant head
pressure.

39. Waterproofing
Hydrophilic vs. Hydrophobic
Hydrophobic or water repellent products such as fatty acid derivatives
(stearates), soaps, oils , silicones and finely divided solids (bentonite, siliceous
powders, etc.), repel water by increasing hydrophobicity. They reduce
absorption but are not enough to resist significant water pressure.
à à
Hydrophilic chemicals absorb and utilize water to catalyze and react with
cement particles to produce elongated crystalline structures. They physically
block pores, cracks and ITZ to sufficiently resist the penetration of water under
pressure.
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40. Waterproofing
Positive and Negative-side Waterproofing
When referring to the positive side
of a waterproofing application, we
are talking about the side where the
water will be coming in contact with
the concrete. The opportunity to
waterproof the positive side is
mostly there only during
construction.
www.basementwaterproofingcoh.com/newconstruct...
Negative side waterproofing is applied to
the inside (dry) face of a structure (or
outside of a reservoir). Easy access to
the dry side makes negative-side
waterproofing the first choice for
remedial projects.

41. Waterproofing
Waterproofing Methods
Water is the most destructive weathering element of concrete structures;
water continues to damage or completely destroy more buildings and
structures than natural disasters. Waterproofing techniques preserve a
structure s integrity and usefulness through an understanding of natural
forces and their effect during life cycle.
Waterproofing
is the formation of an internal or external membrane which is
designed to prevent water from entering or escaping the
concrete. Internal membranes are created with waterproofing
admixtures. External membranes are applied to the surface of
the concrete nearly always on the positive side.
External membranes are divided into two sub-catagories: fluid-applied
membranes and sheet applied membranes.

42. Waterproofing
Waterproofing Methods - Surface Membranes
Fluid-Applied Membranes
Fluid-applied waterproof products are liquid
coatings containing a base of urethanes,
rubbers, plastics, vinyls, polymeric asphalts, or
combinations thereof, which are applied to the
surface usually by spraying or rolling.
www.lexiscoatings.com/neoprene/primer
The fluid-applied membranes are easy to
apply, conform to the surface texture and
irregularities of the concrete and do not have
seams.
www.concretenetwork.com/.../liquid_membranes.htm
Photo by Carolyn Bates

43. Waterproofing
Waterproofing Methods - Surface Membranes
Fluid-Applied Membranes cont d
Fluid-applied membrane applications require that the termination of the
membrane be carefully completed to prevent disbonding at the edge and
potential water infiltration. Blistering will occur if materials are applied to wet
substrates or if water finds its way behind the membrane since they are non-
breathable coatings.
www.crsroof.com/serv_condition.htm
http://www.trsroof.com/Project_Profiles/Marin_Civic_Center_Reroof_Home/Marin_Civic_Center_Background/body_marin_civic_center_background.htm
Controlling thickness during field application is difficult but critical. Thin areas
can be weak. Areas applied too thickly may not cure properly. Fluid applied
systems commonly leave holes in the membrane where they cross bug-holes
and cracks in the concrete. Typically, fluid systems are not durable and will not
resist abrasion or exposure to weathering and UV.

44. Waterproofing
Waterproofing Methods - Surface Membranes
Sheet Membranes
Sheet membrane products are normally
made from thermoplastics, vulcanized
rubbers, and rubberized asphalts. The
sheeting membranes can be applied as
fully bonded to the substrate or
unbonded. In either case, sheets must
be overlapped and bonded to each
other by adhesive or by heat welding.
One exception is bentonite, which is a
clay that swells when wet. It comes in
sheets that are often just laid next to
one another without being bonded.
Apart from bentonite, most sheet membranes tend to be more
durable than fluid applied membranes. They have a consistent
thickness and will bridge openings in the concrete.

45. Waterproofing
Waterproofing Methods - Surface Membranes
Sheet Membranes cont d
Unfortunately, sheet membranes often
suffer from adhesion problems. Surfaces
must be very well prepared, dry and quite
smooth. There is little tolerance for rough
or irregular surfaces. The most obvious
weakness of a sheet membrane system is
the existence of seams throughout the
application. As a result of delamination,
shrinkage, contamination or poor
workmanship it is common for any number
of seams to lose their integrity and allow
water to leak through.
Both surface applied and sheet applied membranes are vulnerable to
puncture damage. And failure of the membrane system for any reason will
allow water to travel under the membrane until it finds the easiest route to
penetrate the concrete. This makes finding and repairing membrane leaks
nearly impossible.

46. Waterproofing
Waterproofing Methods
Internal Waterproofing
Internal waterproofing, also known as integral waterproofing, are products that
perform their function within the pores of the concrete as opposed to on the
surface. These products are designed either to migrate into the concrete from a
surface applied carrier or are mixed right into the concrete during its production.
Integral waterproofing has the significant advantage of being extremely durable.
Because they do not rely on preserving a continuous surface film, they are not
subject to puncturing, tearing or abrasion. They are seamless and generally not
reliant on skilled or careful workmanship in order to perform at their best. The
admixture variety in fact require almost no labor at all and eliminate the need to
schedule access and application time during construction.
Integral waterproofing products can be broadly catagorized as belonging to one
of two major groups: reactive or un-reactive.

47. Waterproofing
Waterproofing Methods Integral Waterproofing
Reactive and Un-reactive
Examples of unreactive products include sodium silicate, bentonite, water
repellents, pozzolans and other SMC s. Some of these may have a reactive
effect during the hardening of new concrete, but they do not reactivate in the
presence of water so as a waterproofing agent they are considered un-
reactive. They function by simply densifying the concrete. Along this same
vein, water reducing admixtures sometimes also claim to produce waterproof
concrete.
or
The un-reactive products attempt to produce waterproof concrete by reducing
its permeability to the point where water can not flow through. However, they
are inadequate when it comes to dealing with the inevitable joints and cracks
that result in all concrete construction.

48. Waterproofing
Waterproofing Methods
Integral Waterproofing
Reactive products, on the other hand, are able to create truly waterproof
structures because they can address moisture penetration through cracks and
joints in addition to the mass concrete. They will respond to moisture by forming
new chemical compounds with grow to seal off the incoming moisture.
Essentially, all truly reactive products are crystalline in nature and grow crystal
formations to block cracks, pores and ITZ.
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49. CRYSTALLINE
TECHNOLOGY

50. Crystalline Technology
Introduction
Although crystalline waterproofing has been used
in Europe and North America for more than 50
years, it is still met with some scepticism. Today,
this method of waterproofing concrete has been
proven effective through successful use in
virtually every country of the world.
The basic idea behind crystalline waterproofing is
to prevent the movement of water through the
concrete by plugging or blocking the natural
pores, capillaries and microcracks found in all
concrete. This stands in contrast to more
conventional means of waterproofing, which
usually involves applying a coating or membrane
to the concrete surface, but is sometimes also
attempted through densification of the concrete.

51. Crystalline Technology
Crystalline Waterproofing Technology
When added or applied to concrete, crystalline
chemicals create a reaction that causes long, narrow
crystals to form and fill the pores, capillaries, and
hairline cracks of the concrete mass. As long as
moisture remains present, crystals continue to grow
throughout the concrete. Once the concrete has
cured and dried, the crystalline chemicals sit
dormant until another dose of water (such as
through a new crack) causes the chemical reaction
to begin again and grow crystals to shut off the
water.

52. Crystalline Technology
Self Sealing
Concrete will often crack due to drying shrinkage, settling, seismic
activity, etc., Water entering through them means you have a leaking
structure even if your concrete is waterproof .
à
The ability of crystalline products to self-seal new cracks in concrete is one of
its most unique and dramatic benefits

53. Crystalline Technology
Self Sealing cont d
Actually, sometimes concrete is able to seal itself off without the help of
crystalline materials. Cracks can become blocked by deposited lime salts or
loose material carried by the flow of water. This is called autogenous healing
and can occur if cracks are very tight less than 0.2mm.
However, most cracks, even cracks much tighter than 0.2mm will continue to
leak especially if subjected to hydrostatic pressure.
Crystalline materials can seal these cracks plus much wider cracks. Most
manufacturers claim crack sealing up to 0.4 or 0.5mm. Real world experiences
often produce specific examples of cracks up to a full millimeter wide being
blocked by crystalline structure.

54. Crystalline Technology
Self Sealing cont d
Incorporating crystalline technology into the concrete ensures that minor
cracking that occurs even years later can self-seal without any intervention
needed. This can help to dramatically reduce the long-term maintenance and
repair costs of a concrete structure.
à à
Crystals can take several days or even weeks to form, but they become a
permanent part of the concrete and will last just as long.

55. Crystalline Technology
Other Benefits
Along with superior waterproofing and self-sealing properties, integral crystalline
waterproofing technology offers a number of key benefits:
Permanent solution becomes a part of the concrete
matrix so it will not crack, peel, tear, or wear-away,
even against high hydrostatic pressure. Unlike
externally applied membranes, which are best on the
day they are applied, crystalline applications become
more effective with time.
Perfect for blind-wall applications can be added to
the concrete mixture or applied to the negative side of
the structure so there is no need to provide access to
the outside of the structure for membrane application.
This gives designers more flexibility and can possibly
allow for a larger building footprint built right to the
property line.

56. Crystalline Technology
Other Benefits cont d
Protects reinforcing steel adds to the longevity of concrete structures by
preventing the penetration of waterborne contaminants and chloride-laden
liquids that cause the corrosion of reinforcing steel.
Save time on construction schedules can be applied to green concrete or
even added to the ready-mix truck. There is no need to wait for membrane
application. Backfilling can begin right-away.

57. Crystalline Technology
How is Crystalline Waterproofing Applied?
Integral Crystalline Waterproofing can be used in existing or new concrete
structures. For existing concrete, crystalline waterproofing is available as a dry
powder, which is mixed with water to form a slurry, then brushed or sprayed
onto concrete surfaces.
For new concrete, crystalline waterproofing can be added as an admixture to
the concrete mixture or spread and troweled into slab surfaces or applied as a
surface treatment.

58. Crystalline Technology
How is Crystalline Waterproofing Applied?
Brush on Method
All crystalline products are supplied as a dry
powder. They are mixed with water to form a
slurry and applied to the inner or outer side of the
concrete structure with a brush, broom, or spray
equipment. The best systems may be applied on
the negative side of the concrete against the
water pressure where access to outside walls
may be difficult or impossible. This allows
concrete to be repaired without digging up the
perimeter, destroying landscaping, and incurring
extra cost.
When applied to existing concrete, crystalline chemicals are absorbed into the
concrete by capillary action and diffusion, and cause the crystals to penetrate
deeply into the concrete. The majority of active crystalline chemicals migrate
into the concrete within the first 28 days, meaning the surface-applied system
can be completely removed from the surface after this time without impacting
its waterproofing properties.

60. Crystalline Technology
How is Crystalline Waterproofing Applied?
Dry Shake Method
When placing concrete slabs, one option is
to apply the crystalline product as a dry
powder to the concrete surface just prior to
finishing. The material is then troweled into
the surface, usually with a power trowel.
This application method has become known
as the dry-shake method .
Using the product in this way has some
advantages over the brush on method
because it is troweled into the surface, the
chemical penetration is immediate; new
concrete has a high moisture content, which
accelerates the chemical reaction and
crystal growth; and, since it becomes part of
the concrete, the surface can be finished
smooth and there is no risk of delamination.

61. Crystalline Technology
How is Crystalline Waterproofing Applied?
Admixture Method
In the case of new concrete construction,
crystalline waterproofing can be added right
into the concrete mix before it is placed. This
application method results in complete, even
and immediate distribution of the crystalline
product throughout the concrete. But most
importantly, the admixture version eliminates
the need to make any kind of surface
application at all. The cost added to the
concrete is more than offset by the savings
gained by eliminating the materials, time and
the labour that would have been required to
apply a product to the surface.
Crystalline waterproofing as an admixture was invented and pioneered by
Kryton International Inc. of Canada during the 1980 s. Since that time,
crystalline waterproofing admixtures have become the preferred replacement
for conventional membranes in new construction.

62. Crystalline Technology
How to Select Crystalline Waterproofing Product
A number of companies offer Integral Crystalline Waterproofing
products for new and existing concrete structures. When selecting
Integral Crystalline Waterproofing products, it is important not to
confuse them with:
§ Products that are simply concrete densifiers or pore blockers
§ Un-reactive products that claim to grow crystals, but actually only
crystallize as they dry.
§ Product that contain stearates, silicones and other hydrophobic
ingredients as these will not reliably resist high hydrostatic
pressures
§ Products based on silicates, clays or talc. These offer temporary
waterproofing at best

63. Crystalline Technology
How to Select Crystalline Waterproofing Product
Select a crystalline waterproofing supplier who can demonstrate a repeated
history of long term success. The manufacturer should offer a long term
warranty and have the company history to back it. The manufacturer
should be able to provide accredited third party test results and have
achieved industry recognized certifications for product quality and
performance.
Most importantly, because of the ongoing value of close technical
support, be sure to select a product from a manufacturer who has
demonstrated the willingness and ability to provide on-site service and
support for major projects anywhere in the world.

64. REFERENCES
[1] Alireza Biparva, PERMEABILITY AND DURABILITY OF HIGH VOLUME FLY ASH CONCRETE UNDER AN
APPLIED COMPRESSIVE STRESS .
[2] Celik Ozyildirim, Temp and permeability
[3] Alvin Olar, Physical Properties and Causes of Deterioration of Construction Materials
[4] Portland Cement Association web site, Durability, Corrosion of Embedded Metals
www.cement.org/tech/cct-dur-corrosion.asp
[5] NPCA Web site, SULFATE ATTACK ON PRECAST CONCRETE
http://www.precast.org/publications/mc/TechArticles/00_Spring_Sulfate.htm
[6] CONCRETE EXPERTS INTERNATIONAL web site, Freeze - Thaw Deterioration of Concrete
http://www.concrete-experts.com/pages/ft.htm
[7] James W. Bryant, Jr, NON-INVASIVE PERMEABILITY ASSESSMENT OF HIGHPERFORMANCE CONCRETE
BRIDGE DECK MIXTURES
[8] A.M. Neville, Properties of Concrete
[9] Kok Seng Chia, Min-Hong Zhang, Water permeability and chloride penetrability of high-strength
lightweight aggregate concrete
[10] National Building Code, NBC 1995
[11] Justin Henshell, Manual of Below-Grade Waterproofing Systems
[12] Michael T. Kubal, Construction Waterproofing
[13] Joe Salmon, Waterproofing
[14] Advanced Cement Technologies, LLC, CONCRETE PERMEABILITY
[15] Bu¨ lent Y lmaz a, Asim Olgun, Studies on cement and mortar containing low-calcium fly ash, limestone, and dolomitic limestone
[16] Raymond W. M. Chan, Report on Concrete Admixtures for Waterproofing Construction
[17] Palmer, W. D., Material Selection Guide: Foundations Waterproofing Materials
[18] Nynke ter Heide, Crack healing in hydrating concrete
[19] Adam Neville, Autogenous Healing- A concrete Miracle

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