Integral Crystalline Waterproofing Technology

Integral Crystalline Waterproofing Technology

Alireza Biparva, B.Sc, M.A.ScAlireza Biparva, B.Sc, M.A.ScCementitious Materials SpecialistCementitious Materials Specialist

&&Kevin Yuers, B.A.Kevin Yuers, B.A.

VP, Technical ServicesVP, Technical ServicesKryton International Inc.Kryton International Inc.

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Table of Contents

1.Concrete and Durability

2.Permeability

3.Waterproofing

4.Crystalline Technology

CONCRETE DURABILITY

Concrete Durability

Concrete BasicsConcrete has been widely used as a major construction material for centuries.Its low cost, versatility, unique engineering properties, and the availability of theconstituent materials makes its utilization more attractive than otherconstruction materials.

A key advantage to the use of concrete is that it can be molded or formed intovirtually any shape when newly mixed, and is strong and durable whenhardened. These qualities explain why concrete can be used to buildskyscrapers, bridges, sidewalks, superhighways, houses, and dams.

michaelscomments.wordpress.com/.../

Concrete is a heterogeneous composite of coarse and fine aggregateparticles held together by cement paste. This paste is the “glue” made fromcement and water that hardens due to a chemical reaction called hydration. Itbinds the aggregate particles into a solid, rock mass material.

Concrete Durability

Concrete Composition

Cement paste ordinarily constitutesabout 25 to 40 % of the totalvolume of concrete. The paste isporous and is prone to watermovement through the pores andmicrocracks present in the paste.

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 withadequate 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 useof the paste.

The quality of the concrete depends upon the quality of the paste and thequality of the aggregate, as well as the bond between the two. In properlymade concrete, each and every particle of aggregate is completely coated withpaste and all of the spaces between the aggregate particles are completelyfilled with paste.

Concrete Durability

Concrete AdmixturesConcrete admixtures are ingredients other than water, aggregates, andhydraulic cement that are added to the concrete mix to modify its properties;they may be extracted from organic materials or they may be artificiallymanufactured.

Admixtures offer various beneficial effects to concrete, including improvedquality, 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.

www.concretethinker.com/Papers.aspx?DocId=2www.cement.org/tech/faq_spalling.asp www.cmaxgrc.com/pp_cruved.html

Chemical admixtures are used to economically modify the concrete to attaincertain properties such as reduction of water or cement content, entrainment ofair, plasticization of fresh concrete, and controlled setting time. In medievaltimes, milk and blood were considered admixtures because of their sublimationeffect on the concrete.

Concrete DurabilityAdmixtures

Chemical Admixtures

www.cement.org/tech/cct_admixtures_AEA.asp

The basic categories of chemical admixturesoutlined in ASTM C494 are:

Type A- Water-reducingType B- RetardingType C- AcceleratingType D- Water-reducing and retardingType E- Water-reducing and acceleratingType F- High range water-reducingType G- High range water-reducing and retarding

Mineral admixtures are supplementary cementitious materials (SCM) such asfly ash, silica fume, and ground granulated blast-furnace slag (GGBFS) areoften added to concrete to make mixtures more economical, less permeable, orto improve other concrete properties.


Mineral Admixtures

Hydraulic activity is how hydraulic cementshydrate, set, and harden when mixed withwater. GGBFS and some Class C fly ashesare SCMs with hydraulic properties. Hydrationof systems containing hydraulic SCMs isgenerally slower than mixtures with onlyPortland cement. www.cement.org/basics/concretebasics_suppleme...

Mineral admixtures are normally residual materials from different industrialprocesses; they contribute to the properties of hardened concrete throughhydraulic or pozzolanic activity.

Concrete DurabilityAdmixtures – Mineral Admixtures

Pozzolanic Activity

Pozzolanic materials react with this lime in the presence of moisture to formadditional cementitious gel. This reaction leads to a reduction in thepermeability of the concrete and an increase in its strength.

Pozzolana are siliceous materials which themselves possess little or nocementitious value but will react chemically with byproducts of cementhydration, such as calcium hydroxide. During the hydration reactionbetween Portland cement and water, a cementitious gel (calcium silicatehydrate) and lime (calcium hydroxide) are formed.

PCA R&D Serial No. 3005 page 91


Miscellaneous AdmixturesSpecialized admixtures that are not considered chemical admixtures ormineral admixtures are categorized as miscellaneous admixtures.Miscellaneous admixtures can provide unique properties to the concrete andcome in many forms. They are comprised of organics, inorganics, synthetics ora combination. Some unique properties that can be achieved are impactresistance, dampproofing, waterproofing, coloring, and increased tensilestrength.

www.eftfibers.com/images/slide.gif

Concrete Durability

DurabilityConcrete durability has been defined as its resistance to degradationprocesses such as weathering, chemical attack, abrasion, impact and physicalstrains.

Ultimately, the durability and life expectancy of the concrete is dependent onthe choice and proportioning of ingredients, the quality of workmanship duringplacing and the conduct of proper curing practices.

Built in 1755 Built in 1970

web.mit.edu/jsf/2004/pantheon.html asp.usatoday.com/.../utils/idmap/13740316.story

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 becompromised.

Concrete Durability

Durability cont’d…In most instances, deterioration in concrete is due to a lack of adequatedurability, rather than deficient strength. Concrete structures can becomeunserviceable due to gradual weakening arising from concrete deteriorationand steel corrosion.

Hence, due to its economic and technical importance, reducing concretedeterioration by increasing its durability has become a challenging problemfacing the industry. The economic loss due to deterioration of concrete and steelcorrosion may constitute up to several percentage points of a country’s grossnational product.

www.corrosion-club.com/concrete1.htm

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Concrete Durability

Degradation Mechanisms Concrete deterioration can be due to adverse mechanical, physical, or chemicalcauses. It is often the case where one or more deteriorative mechanisms are atwork by the time a problem is identified. In fact, in terms of deterioration ofconcrete due to physical or chemical causes, the mobility of fluids or gasesthrough the concrete are nearly always involved.

The overall susceptibility or penetrability of a concrete structure, especiallywhen compounded by additional environmental or exposure challenges, is thekey to its ultimate serviceability and durability. Important degradationmechanisms in concrete structures include the following:

•Corrosion of reinforcing steel•Alkali-aggregate reactions •Carbonation•Sulfate attack •Freezing and thawing

Concrete DurabilityDegradation Mechanisms

Corrosion of Reinforcing SteelConcrete is very strong when loaded under compression, but when stressedunder tension or torsion it is not very strong at all. Hence, it is common practiceto reinforce concrete with steel for improved mechanical properties.

The principal cause of degradation in steel reinforced concrete structures iscorrosion 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...

Concrete DurabilityDegradation Mechanisms -Corrosion of reinforcing steel

Passive LayerSteel embedded in hydrating cement paste forms a passive oxide layerwhich strongly adheres to the steel surface and gives it complete protectionfrom corrosion. This is why rebar does not corrode inside the concrete eventhough it is wet. Maintenance of this passive layer is conditional on anadequately 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 as8.5. At this level, the passive film on the steel is no longer stable and corrosionbegins.


CarbonationCarbonation 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 significantlyincreased in concrete that has a highpermeability due to porous paste, porousaggregates, high water to cementingmaterials ratio, low cement content,short curing period, or poorconsolidation. Carbonation does notactually harm the concrete directly.However, by lowering the pH and thusthe passive layer protection of theembedded steel, expansive corrosion issoon to follow.

www.dundee.ac.uk/.../Carbonation%20Project.htm


Corrosion-FailureCorrosion of reinforcing steel will eventually lead to the failure of the concrete.Steel expands as it corrodes. The resulting stress will generally fracture theconcrete cover. Cracks provide a path for water to carry oxygen and corrosivechemicals to the steel. The process become a death spiral for the concretestructure.

SteelCorrosion Cracking

Expansion Stress

Water & Chemical Ingress


Alkali-Aggregate ReactionsAlkali-aggregate reactivity (AAR) is a reaction between the active mineralconstituents of some aggregates and the sodium and potassium alkalihydroxides in the concrete.

Alkali-aggregate reactivity occurs in two formsi. alkali-silica reaction and ii. alkali-carbonate reaction

Both alkali-silica and alkali- carbonate reactionsresult in swelling of the concrete. The amount ofswelling or expansion depends on the reactivityof the aggregates, the alkalinity of the cementsolution, and the ambient moisture conditions ofthe structure. Indications of the presence ofdeleterious alkali-aggregate reactivity may be inthe form of a network of cracks (map cracking),closed or spalling joints, or displacement ofdifferent portions of a structure.


Sulfate Attack

Sulfate attack on concrete is a relatively rare but complex damagephenomenon caused by exposure of concrete products or structures to anexcessive amount of sulfate – usually in sulfate containing soils.

Sulfates can attack concrete by reacting with hydrated compounds in thehardened cement paste. These expansive reactions can induce sufficientpressure to disrupt the cement paste, resulting in disintegration of theconcrete (loss of paste cohesion and strength).

Design and control of Concrete Mixture book p16


Freezing & Thawing DamageWhen water freezes to ice, it occupies 9% more volume than when it wasliquid. If this water happens to be filling the pores of concrete, the results canbe very damaging. Concrete that is exposed to repeated freezing andthawing cycles when in a saturated condition will quickly deteriorate if notdesigned properly.

To protect concrete from freezingand thawing damage, an air-entraining admixture is added,which creates millions of tiny,closely spaced air bubbles in thehardened concrete. The air bubblesrelieve the pressure build-upcaused by ice formation by actingas tiny expansion chambers.

www.concrete-experts.com/pages/ft.htm


Water Penetration is the Root Cause

Note that in every case, it is the presence of moisture or water within theconcrete that is at the root of each destructive process.

www.concrete-experts.com/pages/ft.htm

PERMEABILITY

Permeability

Durability and PermeabilityIt is well known that permeability determines the vulnerability of concrete toexternal agencies, and in order to be durable, concrete must be relativelyimpervious. Concrete durability depends largely on the ease or difficulty withwhich gases or fluids can migrate through the hardened concrete mass. Asthe permeation of concrete decreases, its durability performance, in terms ofphysicochemical degradation, increases.

Permeation controls the ingress of moisture, ionic, and gaseous species intoconcrete. Given that most deleterious agents are transported through waterand water itself is one of the deleterious agents, the durability of any concretedepends largely on the permeability of concrete. So evaluation of concretepermeability can be used to indirectly estimate its durability.

The durability of concrete is fundamentally based on the permeability of concrete.

Permeability

Transport MechanismsThe ingress of deleterious substances into concrete takes place through the poresystem in the cement matrix or through micro-cracks. There are several factorsthat determine the rate at which a substance is able to flow through the concretematrix including porosity, pore size distribution, pore connectivity, pressuredifferential, and the degree of pore saturation.

The principal ways through which an aggressive substance may transportthrough the concrete matrix are diffusion, capillary action , and permeation. Thetransport of aggressive substances into the concrete matrix may not be due toany single mechanism, but several mechanisms acting simultaneously.

Diffusion

Capillary Action

Permeation

PermeabilityTransport Mechanisms

Diffusion & Capillary Action

Diffusion is the process by which afluid can pass through concrete underthe action of a concentration gradient. Itis defined as the “transfer of mass byrandom motion of free molecules orions in the pore solution resulting in anet flow from regions of higherconcentration to regions of lowerconcentration of the diffusingsubstance”.

Capillary action transports liquids through a porous solid by way of surfacetension acting in the capillary pores. Capillary action is affected by thecharacteristics of both the liquid and the porous medium. The characteristics ofthe liquid that influence capillary action are viscosity, density, and surfacetension. The influencing characteristics of the solid include pore structure(radius, tortuosity, and capillary continuity) and surface energy.

There are a variety of pores andvoids in concrete which can havedirect effects on the permeabilityof concrete. Pores and voids inconcrete can be broadly classifiedas gel pores, capillary pores, andpaste-aggregate interfacial zones.

Permeability can be defined as the ease with which a fluid can flow througha solid. The flow through a media is caused by a pressure differential. Thecoefficient of permeability is the characteristic describing the permeation offluids through a porous material due to a pressure head.

PermeabilityTransport Mechanisms

Permeation

The architecture of the porous body governs the transport properties. The solidphase is composed of hydration products and unhydrated cement grains. Thehydration products are called the gel. The gel contains approximately 28 %porosity and are the smallest interconnected interstitial spaces.

These gel pores are 2-3 nm in nominal diameter – only an order of magnitudelarger than a molecule of water, so gel water is tightly bound. Gel porescontribute to the possibilities of fluid transport across cement paste but in a verylimited way and cannot play a big role in the permeability of concrete.

PermeabilityTransport Mechanisms - Permeation

Gel Porosity

Gel Porosity

As hydration progresses, the capillary pores become segmented. When thecapillary pores are no longer percolated, the permeability decreasesdramatically and the paste is called depercolated paste. Following hydration,capillary pores may become discontinuous if w/cm ratios are low enough.

Capillary pores represent the portion of volume within the cement paste not filledby the products of hydration. The size, distribution and number of capillary poresis determined by the initial ratio of water to cementitious materials and thedegree 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 settingconcrete.

PermeabilityTransport Mechanisms - Permeation

Capillary Porosity

Capillary Porosity

Theoretically, concrete can be described as atwo-phase material: aggregate and cementpaste. Consequently, adding low-permeableaggregates to cement paste should reduce theconcrete’s permeability by interrupting capillarypore continuity in the cement paste matrix.However, test results indicate that the oppositeis true; a considerable increase in permeabilityoccurs when aggregates are added to a pasteor mortar.

In fact, concrete is a three-phase material:aggregate, cement paste, and interfacialtransition zone (ITZ). The ITZ is the area ofcontact between the cement paste and thesurface of the aggregates.

PermeabilityTransport Mechanisms -Permeation

Interfacial Zone Porosity

The porosity of the paste-aggregateinterfacial zone is usually much higherthan the rest of the paste matrix. Thedifferent pore structure of ITZ aroundthe aggregate is due to bleeding, thehigher local w/c ratio, and the influenceof aggregate surface. Also, the particlesize of the aggregate plays an importantrole in the permeability of concrete; thelarger the aggregate size, the greaterthe 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 bulkhydrated cement paste, the paste-aggregate interfacial zone is weaker, carriesleachable compounds, and can be the least resistant path for migratingmoisture and other harmful substances.


Interfacial Zone Porosity

The amount of micro cracks depends on numerousparameters, including aggregate size and grading, cementcontent, w/c ratio, degree of consolidation of fresh concrete,curing conditions, environmental humidity, and thermalhistory of concrete. During the initial stages of hydration, thetransition zone is weak and cracking may occur due tostrains between the cement paste and the aggregate causedby drying shrinkage, thermal strains, and externally appliedloads.

Cracks in concrete generally interconnect flow paths andincrease concrete permeability. The increase in concretepermeability due to crack progression allows more water oraggressive chemical ions to penetrate into the concrete,facilitating further deterioration. Such a chain reaction of“deterioration-cracking, more permeable concrete, furtherdeterioration” may eventually result in destructivedeterioration of the concrete structure.


Micro Cracks

Permeability

Porosity vs. PermeabilityMicro cracks in the cement pastematrix may contribute significantly tothe permeability. In general,connectivity of the pore system is aprerequisite for concrete permeability.Cracks in concrete generallyinterconnect flow paths and increaseconcrete permeability. A highly porousmaterial might perform well as long asthe pores are not interconnected.

High porosity, high permeability

High porosity, low permeability Low porosity, high permeability

Permeability

Water Permeability

Water is the most significant fluid thatflows through concrete. In porousmaterials, water permeability usuallydetermines the rate of deterioration.Water can be directly involved inphysical processes leading todegradation, especially during therepeated freezing and thawing cycles.In addition, water also serves as thecarrying agent for soluble aggressiveions that can be the source of chemicaldegradation.

Low porosity / permeability / penetrability of concrete to moisture is the first lineof defense against frost damage, acid attack, sulfate attack, corrosion of steelembedment and reinforcements, carbonation, alkali-aggregate reaction, andefflorescence and other concrete ailments.

www.tececo.com/technical.porecocrete.php?print

WATERPROOFING

Waterproofing

Dampproofing vs. Waterproofing

Dampproofing and waterproofing products are applied as either a surfacecoating or admixture. Most dampproofing products that get applied to thesurface are coatings and form a physical barrier against water. Dampproofingadmixtures are typically hydrophobic (water-repellent) materials and function byway of surface tension. Dampproofing products are designed to prevent waterfrom absorbing and wicking through concrete that may be damp or wet.Dampproofing products will not resist water under pressure.

For structures exposed to water underhydrostatic pressure, waterproofing isrequired. Waterproofing materials,whether surface applied or admixtures,form a strong physical barrier to water andwill prevent water from entering theconcrete even under a significant headpressure.

Waterproofing

Hydrophilic vs. HydrophobicHydrophobic or water repellent products such as fatty acid derivatives(stearates), soaps, oils , silicones and finely divided solids (bentonite, siliceouspowders, etc.), repel water by increasing hydrophobicity. They reduceabsorption but are not enough to resist significant water pressure.

Hydrophilic chemicals absorb and utilize water to catalyze and react withcement particles to produce elongated crystalline structures. They physicallyblock pores, cracks and ITZ to sufficiently resist the penetration of water underpressure.

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Waterproofing

Positive and Negative-side Waterproofing

When referring to the “positive” sideof a waterproofing application, weare talking about the side where thewater will be coming in contact withthe concrete. The opportunity towaterproof the positive side ismostly there only duringconstruction.

Negative side waterproofing is applied tothe inside (dry) face of a structure (oroutside of a reservoir). Easy access tothe dry side makes negative-sidewaterproofing the first choice forremedial projects.

www.basementwaterproofingcoh.com/newconstruct...

Waterproofing

Waterproofing Methods

Water is the most destructive weathering element of concrete structures;water continues to damage or completely destroy more buildings andstructures than natural disasters. Waterproofing techniques preserve astructure’s integrity and usefulness through an understanding of naturalforces 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-appliedmembranes and sheet applied membranes.

Fluid-applied waterproof products are liquidcoatings containing a base of urethanes,rubbers, plastics, vinyls, polymeric asphalts, orcombinations thereof, which are applied to thesurface usually by spraying or rolling.

WaterproofingWaterproofing Methods - Surface Membranes

Fluid-Applied Membranes

The fluid-applied membranes are easy toapply, conform to the surface texture andirregularities of the concrete and do not haveseams.

www.lexiscoatings.com/neoprene/primer

Photo by Carolyn Bates

www.concretenetwork.com/.../liquid_membranes.htm


Fluid-Applied Membranes cont’d…

Controlling thickness during field application is difficult but critical. Thin areascan be weak. Areas applied too thickly may not cure properly. Fluid appliedsystems commonly leave holes in the membrane where they cross bug-holesand cracks in the concrete. Typically, fluid systems are not durable and will notresist abrasion or exposure to weathering and UV.

Fluid-applied membrane applications require that the termination of themembrane be carefully completed to prevent disbonding at the edge andpotential water infiltration. Blistering will occur if materials are applied to wetsubstrates or if water finds its way behind the membrane since they are non-breathable coatings.

http://www.trsroof.com/Project_Profiles/Marin_Civic_Center_Reroof_Home/Marin_Civic_Center_Background/body_marin_civic_center_background.htm

www.crsroof.com/serv_condition.htm


Sheet Membranes

Sheet membrane products are normallymade from thermoplastics, vulcanizedrubbers, and rubberized asphalts. Thesheeting membranes can be applied asfully bonded to the substrate orunbonded. In either case, sheets mustbe overlapped and bonded to eachother by adhesive or by heat welding.One exception is bentonite, which is aclay that swells when wet. It comes insheets that are often just laid next toone another without being bonded.

Apart from bentonite, most sheet membranes tend to be moredurable than fluid applied membranes. They have a consistentthickness and will bridge openings in the concrete.


Sheet Membranes cont’d…Unfortunately, sheet membranes oftensuffer from adhesion problems. Surfacesmust be very well prepared, dry and quitesmooth. There is little tolerance for roughor irregular surfaces. The most obviousweakness of a sheet membrane system isthe existence of seams throughout theapplication. As a result of delamination,shrinkage, contamination or poorworkmanship it is common for any numberof seams to lose their integrity and allowwater to leak through.

Both surface applied and sheet applied membranes are vulnerable topuncture damage. And failure of the membrane system for any reason willallow water to travel under the membrane until it finds the easiest route topenetrate the concrete. This makes finding and repairing membrane leaksnearly impossible.

Internal waterproofing, also known as integral waterproofing, are products thatperform their function within the pores of the concrete as opposed to on thesurface. These products are designed either to migrate into the concrete from asurface 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 notsubject to puncturing, tearing or abrasion. They are seamless and generally notreliant on skilled or careful workmanship in order to perform at their best. Theadmixture variety in fact require almost no labor at all and eliminate the need toschedule access and application time during construction.

Integral waterproofing products can be broadly catagorized as belonging to oneof two major groups: reactive or un-reactive.

WaterproofingWaterproofing Methods

Internal Waterproofing

Examples of unreactive products include sodium silicate, bentonite, waterrepellents, pozzolans and other SMC’s. Some of these may have a reactiveeffect during the hardening of new concrete, but they do not reactivate in thepresence of water so as a waterproofing agent they are considered un-reactive. They function by simply densifying the concrete. Along this samevein, water reducing admixtures sometimes also claim to produce waterproofconcrete.

WaterproofingWaterproofing Methods – Integral Waterproofing

Reactive and Un-reactive

or

The un-reactive products attempt to produce waterproof concrete by reducingits permeability to the point where water can not flow through. However, theyare inadequate when it comes to dealing with the inevitable joints and cracksthat result in all concrete construction.

WaterproofingWaterproofing Methods

Integral Waterproofing

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Reactive products, on the other hand, are able to create truly waterproofstructures because they can address moisture penetration through cracks andjoints in addition to the mass concrete. They will respond to moisture by formingnew chemical compounds with grow to seal off the incoming moisture.Essentially, all truly reactive products are crystalline in nature and grow crystalformations to block cracks, pores and ITZ.

CRYSTALLINE TECHNOLOGY

Crystalline Technology

Introduction

Although crystalline waterproofing has been usedin Europe and North America for more than 50years, it is still met with some scepticism. Today,this method of waterproofing concrete has beenproven effective through successful use invirtually every country of the world.

The basic idea behind crystalline waterproofing isto prevent the movement of water through theconcrete by plugging or blocking the naturalpores, capillaries and microcracks found in allconcrete. This stands in contrast to moreconventional means of waterproofing, whichusually involves applying a coating or membraneto the concrete surface, but is sometimes alsoattempted through densification of the concrete.


Crystalline Waterproofing TechnologyWhen added or applied to concrete, crystallinechemicals create a reaction that causes long, narrowcrystals to form and fill the pores, capillaries, andhairline cracks of the concrete mass. As long asmoisture remains present, crystals continue to growthroughout the concrete. Once the concrete hascured and dried, the crystalline chemicals sitdormant until another dose of water (such asthrough a new crack) causes the chemical reactionto begin again and grow crystals to shut off thewater.


Self Sealing

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The ability of crystalline products to self-seal new cracks in concrete is one ofits most unique and dramatic benefits

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”.


Self Sealing cont’d…

Actually, sometimes concrete is able to seal itself off without the help ofcrystalline materials. Cracks can become blocked by deposited lime salts orloose material carried by the flow of water. This is called autogenous healingand can occur if cracks are very tight – less than 0.2mm.

However, most cracks, even cracks much tighter than 0.2mm will continue toleak – especially if subjected to hydrostatic pressure.

Crystalline materials can seal these cracks plus much wider cracks. Mostmanufacturers claim crack sealing up to 0.4 or 0.5mm. Real world experiencesoften produce specific examples of cracks up to a full millimeter wide beingblocked by crystalline structure.


Self Sealing cont’d…

Incorporating crystalline technology into the concrete ensures that minorcracking that occurs even years later can self-seal without any interventionneeded. This can help to dramatically reduce the long-term maintenance andrepair costs of a concrete structure.

Crystals can take several days or even weeks to form, but they become apermanent part of the concrete and will last just as long.

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Other BenefitsAlong with superior waterproofing and self-sealing properties, integral crystalline waterproofing technology offers a number of key benefits:

Permanent solution – becomes a part of the concretematrix so it will not crack, peel, tear, or wear-away,even against high hydrostatic pressure. Unlikeexternally applied membranes, which are best on theday they are applied, crystalline applications becomemore effective with time.

Perfect for blind-wall applications – can be added tothe concrete mixture or applied to the negative side ofthe structure so there is no need to provide access tothe outside of the structure for membrane application.This gives designers more flexibility and can possiblyallow for a larger building footprint built right to theproperty line.


Other Benefits cont’d

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.

Protects reinforcing steel – adds to the longevity of concrete structures bypreventing the penetration of waterborne contaminants and chloride-ladenliquids that cause the corrosion of reinforcing steel.


How is Crystalline Waterproofing Applied?

Integral Crystalline Waterproofing can be used in existing or new concretestructures. For existing concrete, crystalline waterproofing is available as a drypowder, which is mixed with water to form a slurry, then brushed or sprayedonto concrete surfaces.

For new concrete, crystalline waterproofing can be added as an admixture tothe concrete mixture or spread and troweled into slab surfaces or applied as asurface treatment.

Crystalline TechnologyHow is Crystalline Waterproofing Applied?

Brush on MethodAll crystalline products are supplied as a drypowder. They are mixed with water to form aslurry and applied to the inner or outer side of theconcrete structure with a brush, broom, or sprayequipment. The best systems may be applied onthe negative side of the concrete against thewater pressure where access to outside wallsmay be difficult or impossible. This allowsconcrete to be repaired without digging up theperimeter, destroying landscaping, and incurringextra cost.

When applied to existing concrete, crystalline chemicals are absorbed into theconcrete by capillary action and diffusion, and cause the crystals to penetratedeeply into the concrete. The majority of active crystalline chemicals migrateinto the concrete within the first 28 days, meaning the surface-applied systemcan be completely removed from the surface after this time without impactingits waterproofing properties.


Dry Shake MethodWhen placing concrete slabs, one option isto apply the crystalline product as a drypowder to the concrete surface just prior tofinishing. The material is then troweled intothe surface, usually with a power trowel.This application method has become knownas the “dry-shake method”.

Using the product in this way has someadvantages over the brush on method—because it is troweled into the surface, thechemical penetration is immediate; newconcrete has a high moisture content, whichaccelerates the chemical reaction andcrystal growth; and, since it becomes part ofthe concrete, the surface can be finishedsmooth and there is no risk of delamination.


Admixture MethodIn the case of new concrete construction,crystalline waterproofing can be added rightinto the concrete mix before it is placed. Thisapplication method results in complete, evenand immediate distribution of the crystallineproduct throughout the concrete. But mostimportantly, the admixture version eliminatesthe need to make any kind of surfaceapplication at all. The cost added to theconcrete is more than offset by the savingsgained by eliminating the materials, time andthe labour that would have been required toapply a product to the surface.

Crystalline waterproofing as an admixture was invented and pioneered byKryton International Inc. of Canada during the 1980’s. Since that time,crystalline waterproofing admixtures have become the preferred replacementfor conventional membranes in new construction.


How to Select Crystalline Waterproofing Product

A number of companies offer Integral Crystalline Waterproofingproducts for new and existing concrete structures. When selectingIntegral Crystalline Waterproofing products, it is important not toconfuse 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 hydrostaticpressures

§ Products based on silicates, clays or talc. These offer temporarywaterproofing at best


How to Select Crystalline Waterproofing Product

Select a crystalline waterproofing supplier who can demonstrate a repeatedhistory of long term success. The manufacturer should offer a long termwarranty and have the company history to back it. The manufacturershould be able to provide accredited third party test results and haveachieved industry recognized certifications for product quality andperformance.

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.

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 Yılmaz 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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Integral Crystalline Waterproofing Technology

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