Water Proofing Technology

Water proofing technology

Keywords: waterproofin, Hydrophilic, hydrophobic, membranes, crystalline

1. IntroductionThe purpose of a shelter is to protect us from the elements. Yet, even today, the structures are contaminated by natural elements one of them is water, which comes from rainwater, surface water or ground water. To avoid this problem waterproofing, process which is designed to prevent water from penetrating a structure, is adopted. Usually extensive waterproofing measures are added to a building at the time of construction and it may also be done after a building is built.

2. Waterproofing and envelope designWater proofing Is the combination of materials or systems that prevents water from interring in to the structural element of a building or its finished spaces. Waterproofing and envelope design incorporates the following steps to ensure the safety of the structure from the water damage;y y y

Understanding water sources. Designing system to prevent leakage. Finalizing the design by properly detailing each individual envelope component into adjacent components.

Modern building materials, such as hard bricks; cement-based mortars and renders; modern masonry paints; and external sealants are specifically designed to keep moisture out of the building by providing an impervious physical barrier. Cavity

walls and cement renders protect the building from driving rain and damp-proof courses prevent moisture rising from the ground. Used correctly in the construction of new buildings, such materials and methods are perfectly acceptable and will exclude the elements (as long as they are maintained). However, it is important to understand that these methods are rarely appropriate for older buildings.

Fig 1 cracked cement in brick joints and cracked concrete Table 1- the differences between traditional and modern building construction.

Traditional mass wall construction Relies on the mass of the wall for weatherproofing'. Built with soft, porous, flexible, breathable' materials. Absorbs moisture and allows quick, natural drying.Relies on natural ventilation to control the internal environment and prevent condensation and mould growth etc.

Modern cavity wall construction Relies on waterproof' materials.Built with hard, impervious and inflexible materials. Physical break (cavity) to prevent moisture transferring to the inside of building. Relies on mechanical extraction and physical ventilation to control the internal environment and prevent condensation and mould growth etc.

3. ConcreteConcrete is the construction material, which is a mixture of cement, aggregates, water, reinforcing materials, chemical and mineral admixtures. Where the aggregate includes sand and gravel, for reinforcing material is mostly metal bars and also glass and plastic fibers, and for chemical admixture add special characteristics to the plain concrete.

Fig. 2 concrete mix

4. Waterproofing systemThe most common and important systems are integral water proofing system and others that uses membranes. Hydrophilic system and hydrophobic systems are subtypes of integral water proofing systems. The most popular Hydrophilic water proofing system is crystalline technology, it prevent water by covering the concrete in to isolated crystal. Other Hydrophilic water proofing system uses hydraulic swelling, which swell the concrete as it absorb water, eventually it filles pore spaces presented in the concrete. And in hydrophobic systems externally applied product such us coatings, membranes and so on, are used.

4.1. MembranesWater proofing membranes can be either liquid or sheet membranes. The liquid membranes are sprayed on concrete, forming a rubber like coating about 60 mm thick on the concrete surface. It can be applied quickly and the cost is also low. And the sheet membranes are presented from asphalt. These membranes are laminated to polythene films and the sheets thus forms are then pasted on to the concrete. This are mostly applied to protect foundation walls, parking lots, tunnels and so on. But the labor cost for this system is very high, because it has to be pasted manually. Because concrete is porous, external surface applied membranes are used to keep water out.

Fig. 3 spray waterproofing and membranes waterproofing Problem with the use of membranes y y y y y y A lot of pain with external protection systems Requires nearly 100% perfect workmanship. Risk of weather delay. Vulnerable to damage. Expensive or impossible to repair. Typically not recyclable.

4.2. Hydrophobic concreteUnlike the hydrophobic membranes hydrophobic concrete is totally a different and innovative concept Insted of applying any external agent to the concrete for waterproof here the concrete itself is manufactured as waterproof. The concrete is made hydrophobic by adding admixture, like hycrete TM(detail explanation is shown in section 6), to it at the time of production. These admixture stop capillary action occurring in the concrete.It also protects steel reinforcement from corrosion by repelling water and chlorides and by creating a monolayer of protection on the reinforcement itselfIt produces a reversed angle of contact so that the surface tension forces push the water out of the capillary pores in the concrete. This kind of waterproof successfully used in Asia, Europe and Australia. It allows construction to carry on even in the rains.

4.3. Crystalline waterproofingLet's see how this technology can be used as an option to Integral Waterproofing System. First of all, the concrete which has to be waterproofed is saturated with water and then a low density solution is applied, followed by the crystalline waterproofing material, which is a high density solution. After this, the chemical diffusion process starts. The high density crystalline waterproofing solution seeps inside the concrete and travels towards the low density solution until an equilibrium is attained. Since water is applied to the concrete, cement hydration occurs. This hydrated cement now reacts with the crystalline material to form crystals inside the concrete. The diffusion process may take this crystalline waterproofing 12 inches inside the wall. This waterproofing is highly efficient, because crystals that are formed within the concrete remain protected from any kind of external damage. Resistance to 130 degree heat in a constant state is another advantage of this kind of waterproofing. It also resists chemical reactions like carbonation - which reduces alkalinity and damages the concrete. It stops chloride ion diffusion in the wall, protecting the steel present in the concrete from oxidation and also expansion. why do we use crystalline waterproofing? No external membranes waterproofing built in Fast, easy installation lower cost up to 40% Shave weeks off construction schedules

5. Problems because of waters 5.1. Problems with basements and indoor concrete

Wet basement water seeping through concrete walls or floor Cracks in basement walls Cracks in concrete floors Leaking floor-to-wall joints or expansion control joints Leaking form ties or pipe penetrations Efflorescence - the sign of beginning water seepage Radon gas seeping through concrete and openings Flooded basement - a sump pump or power failure Damp basement water vapor infiltration Molds and mildew Musty odors Condensation - in basements or on garage floors Concrete dusting harmful to the lungs and machinery Sump pump failure backup sump pump needed

Fig.4 Problems with basements and indoor concrete

5.2. Problem with outdoor concrete, bricks and masonry Spalling or pitting of driveways and outdoor concrete due to freeze/thaw cycle and road salts Cracks in driveways, pool decks, and patios Leaking brick walls and chimneys due to wind-driven rain Crumbling bricks Efflorescence on concrete or brick walls, and pavers Deteriorating stone or masonry walls Pool decks - cracks, pit marks, deterioration Cracks in swimming pools Leaking fish ponds Deterioration of concrete in marinas due to wind-carried salts Algae growth on outdoor concrete or bricks Concrete needs staining

Fig.5 Problems with outdoor concrete, bricks and masonry

6. Example of water proofing material 6.1. Penetron systemPENETRON Cementitious Capillary Waterproofing Products are formulations consisting of common cement, quartz, sand (of special grade) and multiple activating chemicals that provide the most effective permanent concrete waterproofing system available.

6.1.1. How it works The PENETRON chemicals penetrate into the the capillary tracts of the concrete by pressure of osmosis, Brownian movement and dry particle reactions. The active ingredients of PENETRON react with various concrete minerals forming insoluble crystals which fill out cracks, pores and voids up to a width of at least 400 microns. This crystalline growth will eventually take place deep inside the concrete structure and has been found as deep as nearly 1 meter from the point of application.

Water molecules (and a wide range of chemicals) are no longer able to pass through the concrete. However, air can still pass allowing the concrete to breathe and avoiding vapor pressure to build. In the absence of further moisture, PENETRON components lie dormant. Should moisture recur at any time, the sealing process resumes automatically and advances ever deeper into the concrete.

Fig.6 Coarse-grained elongated crystals and fine-grained needle-like crystals can be seen lining a crack. These crystals will completely fill up and waterproof the crack.

Fig.7 Same crack as above taken by BEI showing Penetron crystal formation sealing it.

Fig.8 BEI close up showing elongated crystals and fine needle-like crystals in the crack

6.1.2. Typical usagePENETRON should be applied to concrete or block structures exposed to potential water or chemical attack and thus requiring permanent waterproofing and protection. It's applicability to either the positive side (side exposed to water) or the negative side(side opposite water) meets all waterproofing requirements. Here are just a few examples:

y y

Drinking Water Reservoirs Sewage and Water treatment tanks Aquariums Tunnels Foundations Elevator Shafts Underground vaults

y y y y y y y y

Industrial Installations Parking Decks Traffic Bearing Structures Base Slabs Diaphragm Walls Basements Concrete Roofs Bathrooms

y y y y y

Fig.. 9 Type of usages

6.1.3. Unique advantagesPENETRON should not be confused with a coating or membrane solution. It actually becomes an integral part of the concrete, forming a complete body of strength and durability. The system therefore offers the following benefits:y y y y y

Penetrates deeply...up to 1 meter ! Seals concrete's capillary tracts and cracks up to 0.4mm. Permanent; waterproofing and chemical resistance properties remain intact even after surface damage. Cannot come apart at the seams, tear or puncture. More effective and less costly than other systems such as membranes, cla y panels, pore blockers, coatings... Easy to apply and therefore highly labor-cost effective. Can be applied from either the positive or the negative side. Resists high hydrostatic head pressure. Increases compressive strength of concrete. Does not require protection during backfilling, placement of steel or wire mesh or other common procedures. Resists chemical attack and provides a wide range of protection from freezethaw cycles, corrosion of reinforcement steel, aggressive sub-soil waters, sea water, carbonates, chlorides, sulfates and nitrates. Can be applied to moist or green concrete. Can be applied as a slurry (brush or spray), dry-shake or admixture.

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6.2. Hycrete Hycretes hydrophobic concrete admixtures start life as water-soluble, environmentally friendly, Cradle To Cradle certified materials. Dosed into concrete, they combine with metallic ions supplied by cement, forming water-insoluble polymers, and can increase concrete durability. Those polymers act in two ways:

a) Hydrophobic Pore Blocking. The polymers in Hycrete admixtures block pores in the concrete. The absorption of water in the concrete is dramatically reduced. Water and absorbed salts stay out of the concrete. b) Corrosion Inhibition. Ionic in nature, the molecules in Hycrete admixtures also bind to the surface of any steel reinforcement in the concrete, forming passivating layers and minimizing rebar corrosion. Hycrete admixtures also barrier diffusion of ions through water that does absorb into the concrete, providing an extra layer of defense against corrosive agents, giving superior rebar protection.

Fig. 10 Hydrophobic Pore Blocking and Corrosion Inhibition

6.2.1.Resultsy

Reduced water absorption in concrete (% on y-axis). Hycrete admixtures keep water out of concrete.

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Corrosion resistance climbs. Rebar iron loss falls greatly when compared to controls or the industrys leading incumbent inhibitor.

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Reference[1] Michael T.Kubal ,,construction waterproofing handbook, second edition, NorthCarolina, McGraw-Hill, 2008 [2] P.H.Perkins ,,Repair, protection and waterproofing of concrete structures Third edition, France, Taylor and Francis-Library,2003 [3]Different journal and factory brochure from the internet