Time constraint, poor workmanship, varied quality of concrete, difficult terrains, are among concerns while waterproofing structures.

Waterproofing plays a crucial role in enhancing life of structures, both new as well as those that have significantly deteriorated but cannot be dismantled due to cost considerations. Effective waterproofing as such does not determine the strength of concrete but is pivotal in enhancing the durability and life of concrete. Waterproofing is the barrier between deteriorating media, i.e. water and the concrete, protecting it from long-term deterioration.

Sealant systems
Tremco adds value to this segment by providing very high-tech solutions, that have a tremendously long life as well as are quick and easy to apply. “Our TREMproof Waterproofing Systems, Vulkem Traffic Resistant Systems, Dymonic Sealants and AlphaGuardTM Roof Coatings all ensure that the repaired structure can be brought back into service in a very short time, sometimes within a couple of days after casting. Our sealant systems play an important role in the maintenance of structures and increases the durability and thus the service life of the structures,” says Sunny Surlaker, Head: Marketing and Technical Communication, Tremco India Pvt Ltd.

Quantity of cement
The strength of concrete is determined mainly by the quantity of cement in the mix, W/C ratio. Concrete admixtures help’s in attaining the desired strength, by modifying the properties of the mix. Waterproofing can prevent intrusion of water into concrete, which may result in lower of the PH of concrete over time and ultimately result in corrosion of reinforcement, which ultimately weakens the structure, says Hasan Rizvi, Sr. Vice President, STP Ltd.

Effective admixture
The true strength of concrete is not the immediate strength, with an effective waterproofing solution this can be seen and tested. An effective waterproofing is the one which gradually increases the strength.

Admixtures are an effective way to waterproof concrete structures and increase the strength of the concrete and an effective admixture is the one which helps in hydration and is effective for a longer period, according to Umesh Kakkar, Managing Director, Kryton Buildmat.

There are a variety of waterproofing admixtures available in the market. Most of the available admixtures react with lime (by-product of concrete) and eat away most of the lime causing corrosion to start in the re-bar over time. Also, as an industry we commonly use pozzolana like materials (silica fume and fly ash) that react with free lime and make calcium silicate, hence reducing the free lime available for reaction with the admixtures.

An effective admixture is one which reacts with un-hydrated cement and moisture to create needle like crystals and seal cracks up to 0.5mm. This kind of an admixture becomes dormant within the concrete only to develop crystals once in contact with moisture. It becomes a part of the concrete and adds strength to the concrete and durability to the structure. These needle-like crystals grow in the small pores of concrete and stop the passage way for water. The more common spherical crystals don’t, he adds.

Major challenges faced using waterproofing solutions for construction
India is seeing a growth spurt in urbanisation. “As we continue to build bigger, faster and deeper reinforced concrete is the material of choice to meet the needs of speed and durability. By virtue of the structure of the concrete paste, it is this component of the concrete that is susceptible to porosity, capillarity and cracks. This makes concrete the hydrophilic, absorptive material that it is,” says Surlaker.

Due to the speed and nature of building today, the efficiency of waterproofing systems is not able to keep pace with construction. A reliable system installed by professionals is essential to protect the structure from water damage.

Performance – a key factor
In reality, the most important factor for waterproofing treatments is performance. Materials and systems should be tested for capillary absorption as well as penetration under hydrostatic pressure. Such tests are referred to in ASTM / EN codes and materials can be tested in many labs across India now to evaluate conformity to ASTM/EN standards. Waterproofing problems continuously crop up, not due to bad materials, but due to the increasing complexity of construction, disregard for sound principles of waterproofing, and lack of co-ordination between various functions and components of today’s building systems.

Considering building or industrial structures, there are 5 key areas that are historically pain or pressure points in effective waterproofing.

• Cracks and voids
• Joints and interfaces (construction and expansion joints, material, dimensional interfaces)
• Underground structures (Tanks, basements, etc.)
• Trafficable surfaces (Podiums, terraces, car parks, ramps, etc.)
• Roof waterproofing (Flat as well as sloping, metal or concrete roofs)

As the structures get bigger and the performance requirements get tougher, the usage of materials will have to evolve from using simple cement-based materials to systems involving new age hybrid polyurethane and acrylic based chemistry. These challenges need to be addressed and here, new technologies as those from Tremco can help.

Time constraint and poor workmanship
There are several problems which any site encounters during application of waterproofing for structures time constraint and poor workmanship are the main points followed closely by complicated application system, varied quality of concrete, bad surface preparation, using poor quality materials, difficult terrains and major variation in weather. “All these challenges together lead to bad construction practices which cause failure in waterproofing system and decrease the durability of the structure. A waterproofing system that is a solution to all these problems and will last under high hydrostatic pressure is truly effective waterproofing,” says Kakkar.

A perfect example of such a waterproofing solution is KIM (Krystol Internal Membrane). KIM is mixed during the concrete pour, making it an economical, and convenient waterproofing system. KIM’s unique system works with moisture and un-hydrated cement particles to form million needle like crystals that block the pores and self-seals cracks of up to 0.5mm. KIM is different and it is one of the only admixtures that does not react with free lime and is safe to use with potable water. Once mixed in to the concrete, KIM along with the concrete can be poured directly over the P.C.C. eliminating the cost and time wasted of overlaying systems like coatings etc.
Differences in matter: Not just in chemical properties, but also in physical properties
KIM is a multi-award-winning admixture with Kryton’s unique Krystol technology that is different in terms of not just its chemical properties, but also physical properties. Once the concrete has cured, the crystalline chemicals sit dormant until another dose of water (such as through a new crack) causes the chemical reaction to begin again. This system is easy to use, stands strong even under high hydrostatic pressure and is effective under varied temperatures.

Liquid applied waterproofing systems are easy to apply specially in difficult areas as compared to preformed membranes, opines Rizvi.

Selection criteria for waterproofing
Waterproofing ensures good corrosion resistance and reduces the impact of ageing in the structure, says Manish Naik, DGM- Business Development, The Supreme Industries.

The major sources of water exposure to the structures are large coastal area, areas surrounding with water bodies, seepage of groundwater, moisture content in the air (humidity) and rains. Due to porous nature of concrete with aggregates, preventing or avoiding exposure to excess water is a challenge. Considering waterproofing as the ultimate solution to address such challenges. There are various methods available for waterproofing and the treatment is selected based on following criteria, such as reliability, ease of application, repairing and cost effectiveness.

Buyer has option
Today buyer has a choice of waterproofing treatment solutions available at their disposal, to select chemicals and coatings with a proper and in-depth study as treatment performance will depend on selecting the right kind of product,” adds Naik.

Several world-renowned chemicals available however; its performance in typical Indian climate and its reactions with Indian conditions should be verified as the effect of waterproofing failures may not be visible immediately after the treatment is done. In such case, the selection of chemicals and coatings should be done based on product’s performance as many of them will not be able to meet the desired results. The important factors that affect the performance are; type of chemical used, applicator’s skills in applying the product, method of treatment and use of resilient protection board.

Our sealant systems play an important role in the maintenance of structures and increases the durability and thus the service life of the structures.
Sunny Surlaker, Head: Marketing and Technical Communication, Tremco India Pvt Ltd

Liquid applied waterproofing systems are easy to apply specially in difficult areas as compared to preformed membranes.
Hasan Rizvi, Sr. Vice President, STP Ltd

An effective admixture is one which reacts with un-hydrated cement and moisture to create needle like crystals and seal cracks up to 0.5mm.
Umesh Kakkar, Managing Director, Kryton Buildmat

Waterproofing plays a safeguarding role in ensuring good corrosion resistance and reducing the impact of ageing in the structure.
Manish Naik, DGM- Business Development, The Supreme Industries