Integral Crystalline Waterproofing Technology

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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.

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Integral Crystalline Waterproofing Technology

  1. 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. 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. 3. Table of Contents 1.Concrete and Durability 2.Permeability 3.Waterproofing 4.Crystalline Technology
  4. 4. CONCRETE DURABILITY
  5. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 25. PERMEABILITY
  26. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 37. WATERPROOFING
  38. 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. 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. à à
  40. 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. 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. 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. 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. 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. 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. 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. 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. 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. à à
  49. 49. CRYSTALLINE TECHNOLOGY
  50. 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. 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. 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. 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. 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. 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. 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. 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. 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.
  59. 59. 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.
  60. 60. 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.
  61. 61. 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
  62. 62. 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.
  63. 63. 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
  64. 64. 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

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