Chemicals for all Seasons

01 May 2012 Editorial Team

Construction chemicals that are in demand across the world are now being used increasingly in India, discovers Charu Bahri.

It's inarguable that the widening range of available construction chemicals has utterly transformed construction methodologies. Today, concrete is rarely placed without a concrete admixture. Whether it is curing, releasing forms, sealing, repairing, preserving or protecting, construction chemicals are a necessity.

Demand on the rise

A medley of infrastructure projects – planned and underway – across the country will grow the demand for construction chemicals at a good clip in the coming years. Power projects, transport networks, dams, irrigation projects, airports and ports, commercial and residential developments and the rehabilitation and repair of ageing structures will continue to support the growth of the industry.

"Demand comes not only from construction purposes but also for the operations of infrastructure," observes Swapnil R Deshmukh, Marketing Manager, Chembond Chemicals Ltd. "For instance, grouts and anchors find favour in the construction of power plants, airports, roads, bridges, dams and ports. Waterproofing, sealing and joining products are needed for underground works for metros, underpasses and tunnels. These include shotcrete accelerators, hydrophilic water stops, epoxy bonding and joining agents, PU and epoxy injection resins and foams, polysulfide and polyurethane joint sealants. On the other hand, jet fuel resistant joint sealants and fast patching compounds are essential to repair damaged airport runways and ensure the early restoration of traffic."

Towards better adoption

That said, Ewart Lazarus, Executive Director, Chowgule Construction Technologies Pvt Ltd, believes India is still a few years away from 100 per cent adoption of construction chemicals. "Many construction companies still view these products as an optional value-add," he says. "The construction market is expected to grow at more than 30 per cent per annum in the next few years, which, I believe will translate into a growth of about 18 to 25 per cent of the construction chemical industry. If more industry members embrace the usage of these products, especially if chemicals are included in project specifications as is common practice in developed economies, the industry will expand faster."

According to Gangadharan Manari, Managing Director, Cera-Chem Pvt Ltd, "The value of the construction chemicals business in India is estimated to be about Rs 1,650 crore per annum. Demand is growing for the wide range of high-end construction chemicals available; our own products have been used in leading infrastructure projects such as Hyderabad International Airport, Delhi Metro, north Chennai port, etc. Still, manufacturers must also take responsibility for promoting the use of chemicals by creating awareness about the benefits of their products, especially in terms of speedy construction and durability of structures."

He informs us that the Construction Chemicals Manufacturers' Association is also helping promote reputed construction chemicals. "Unorganised small operators in this sector, many of which are fly-by-night operators who offer cheap products, shake the confidence of customers owing to non-performance and the consequential damages they suffer," Manari adds. "The association should consider introducing a minimum standard for any product."

Industry trends

In Deshmukh's view, industry trends are the outcome of the emerging concerns of construction chemical users as well as manufacturers. "Sustainability of construction and the construction process is a major focus as a result of environmental concerns and the availability of key raw materials," he points out. "Advances in performance aim to meet these challenges. Time constraint is another challenge, as is the need to construct high-rise structures meeting increasingly stringent earthquake standards." Deshmukh also sees a need to train construction manpower to further the adoption of newer construction techniques and technologies.

Chowgule is focusing on a two-pronged strategy to enhance its position in the market – not only is it focusing on infrastructure, retail and housing development projects with its broad suite of products and turnkey consultants but the company is also widening its certified applicator network to cover the residential, renovation and repair market.

Construction chemical industry trends are also following the kind of projects being taken up. For instance, as more metro rail, commercial, utility and condominium projects are unrolled, clients and contractors are showing an inclination towards mechanically adhered fully bonded systems for basement waterproofing because of the unique features offered. "Ideally, pre-applied polyethylene and polypropylene fully-bonded systems establish a mechanical bond with the poured concrete. These are best suited to provide a durable and sustainable solution for basement waterproofing, having adequate thickness to facilitate direct placing of membrane on the compacted soil and allowing direct placing of rebars without the protection screed saving time and cost," says Nagaraj BS, Product Segment Manager, Fosroc Chemicals (India) Pvt Ltd.

In a segment that is populated by other solutions such as APP/SBS-based torchon and self-adhesive membranes, loose-laid PVC and EPDM membranes, chemically bonded HDPE films, etc, mechanically adhered, fully-bonded solutions address the need for effective, easy, swift basement waterproofing that takes care of critical issues like differential settlement, water tracking between the membrane and substrate and installation of the system in wet basement conditions.

Focus on R&D

In order to develop product profiles to meet emerging demand and keep up with the wide range of products offered by multinational players in the industry, futuristic Indian companies are also increasingly seeing a benefit in combining international know-how with knowledge of the local environment to create tailor-made solutions for Indian conditions. "We offer a portfolio of products that is a carefully researched mix of German excellence and Indian innovation," says Lazarus. "Over and above that, Chowgule's team of in-house experts work with the local site team to ensure that we get it right the first time. We aim and mostly achieve a zero failure or rework rate."

"Our R&D focus area is to develop products meeting environment-friendly conditions at a competitive price without compromising on quality and performance," says Manari. "We are also focusing on products that help contractors meet tight deadlines. Cera-Chem's high-performance integral waterproofing product, which works on the theory of capillary crystallisation, is being used for the waterproofing of underground and water-retaining structures at the time of concreting itself. We have successfully marketed and used this product in critical applications in south India, and are planning to launch it on an all-India basis this year. Products for repair and rehabilitation and retailing small user-friendly packages are important segments as they help tide over construction slowdowns."

With promises of zero failure, construction chemicals will only find more takers with time.

Case Study 1: Repair Works

Project: Repair of Salt Works Jetty Repair, a 10-year-old barge loading jetty in Gujarat
Project timeline: February to May 2010, a record five months
Location: Shores of Hansthal Creek near the port of Navlakhi near Balamba village, Jamnagar
Technical specifications: The jetty is about 800 ft (245 m) long connected by a berth of 200 ft (61 m). The approach path comprises a deck slab with RCC beams resting on RCC piles 2.5 ft (0.75 m) in diameter, at a distance of 33 ft (10.1 m) centre to centre. The span of the slab is 27 ft (8.3 m). A conveyer belt is installed with supports over the deck slab to transport the salt to the berthing deck.
Conditions at site: Continuous exposure of the structure to seawater and air had caused high deterioration of concrete on the underside of the jetty slab, main and cross beams and piles caps, owing to heavy chloride ingress in the concrete. Concrete is permeable to water and solutions of chloride and sulphate. Penetration of the solution of these chemicals produces a gradual change in the condition within the concrete, ultimately leading to corrosion of steel and deterioration of concrete.
Equipment used: Drilling machines, concrete breakers, high power water jet, concrete/mortar mechanised mixers, polyurethane injection pumps and concrete/mortar spray equipment
Products used: "We used cement-based high strength repair mortars, polyurethane flexible injection resins and high-performance acrylic coatings based on German technology," says Ewart Lazarus, Executive Director, Chowgule Construction Technologies Pvt Ltd. "The cement-based, high-strength repair mortar, applied in layers of 20 mm each, interspaced with curing, is a combination of an anti-corrosive coat, key coat for steel and concrete, waterproof and non-shrink mortar and concrete or plaster finish, all in a single product."
Key challenges faced: Harsh weather conditions and sea tides, which made working conditions precarious; absence of utilities like electricity and water supply owing to the remoteness of the location; and the deteriorated state of the under-deck portion, which necessitated the erection of a suspended all metal scaffolding with adequately strong platform and installation of high-strength double safety nets to provide a safe and durable environment for the men and equipment.

Case Study 2: Basement Waterproofing

Project: Construction of BVR Mall, a PVP Square project, for which consultancy was provided by Design Tree Service Consultants Pvt Ltd
Timeline: Ongoing
Location: Vijayawada, Andhra Pradesh
requirements: The mall design includes three basement levels, the lowest of which reaches 12 m below ground level.
Conditions at site: The water table is very high; the city located close to the coastline is prone to cyclones and sees heavy rain; the basement construction demanded the installation of four 62H capacity pumps and 16 bore wells with a dewatering rate of
400 litre per minute. The sandy soil substrate also posed the threat of differential settlement of the raft foundation and collapse of benching done for basement excavation. The retaining wall flushed with the secant piling, thus creating no working space for installation of the waterproofing system.
Key challenges: The client was looking for a solution capable of addressing multiple issues:

• Dewatering system: This should be in place and continuous till the raft concreting is complete. This demands the installation of perforated pipes and pressure relief valves that could be taken across through the membrane.
• Differential settlement: Sandy soil substrate can lead to differential settlement of the foundation below raft.
• Time-saving and cost-saving: Protection screed on the waterproofing membrane and re-profiling of secant piles surface using shotcreting should not be mandatory, as this activity demands additional time and cost.
• Amenable to easy cleaning: This was a must given the local conditions, tendency to see high rainfall leading to sand and slush deposit during execution of waterproofing.
• Quick and easy to install: The waterproofing should be a parallel activity with concreting rather than an independent activity.
• Positive side waterproofing: Waterproofing for the retaining wall shall be installed from the positive side in the absence of
working space.
Solution: "We offered the client our Proofex Engage System, which met all its requirements," says Nagaraj BS, Product Segment Manager, Fosroc Chemicals (I) Pvt Ltd. "It is a fully-bonded system with a mechanical bond to the poured concrete with non-tracking property. There is no possibility of bond failure. A unique mesh provides water tightness for every square mm of concrete, and the membrane stays in place in case of differential settlement of raft foundation. The thickness of the membrane is a minimum 4 mm, which enables the direct placing of rebars on the membrane without protection screed, thus saving time and the cost of protection screed. Installation of the membrane is both easy and rapid. The 1.27 m × 30 m membrane is unrolled and overlapped using selvedge inbuilt with the membrane. Thus, waterproofing can keep pace with concreting. As it is a pre-applied system, installation takes place with minimum surface preparation even in wet conditions. Sand and slush deposits are easily cleaned using air and a water jet. For the retaining wall, the membrane was fixed to sacrificial shuttering provided on the secant pile to achieve positive side waterproofing. This eliminated the demand for re-profiling the secant piles with shotcreting. Re-used ply was simply used for re-profiling the secant piles."

Case Study 3: Roof Waterproofing

Project: Renault Nissan Automotives India Pvt Ltd's state-of-the-art manufacturing unit Project timeline: Two months in 2009 Location: Sipcot Industrial Estate, Oragadam, Chennai
Technical specification: The project design includes a headquarters block, the roof of which had to be made watertight to avoid problems in future. The area of the roof is about 2,341 sq m.
Product used: "We proposed Sika's Sarnafil waterproofing solution for roofs," explains Samik Dutta, Assistant Manager-Marketing, Sika India Pvt. Ltd. "It is a PVC membrane system with a mechanical fastening system. Separate membrane systems are available for horizontal and vertical applications, and both were used in this particular instance. To achieve complete waterproofing, a geo-textile of 150 gsm was laid over a 30 mm thick insulation board. Then, Sarnafil S-327 12 L was laid and mechanically fastened using BD fasteners. Special protection was given over the fasteners. The vertical wall was covered with Sarnafil G 410 12 adhered with Sarnacol 606. The process makes use of an S-U bar, welding chord and termination bar. The detailing for the corners and brace beams was given special attention to ensure no leakages at weak spots."
Key challenges: While there were no significant challenges at the site, to ensure the best outcome of the product, a company-trained applicator was brought into the project. Civichem & Applications was entrusted with the task of applying the product.

Case Study 4: Internationally Renowned Products in India

Project: Burj Khalifa
Project timeline: Opened in January 2010
Technical specifications: It stands over 800 m tall, making it the tallest building in the world.
Key challenges:
• The concrete mix for the structural core of the tower had to be made capable of being pumped to formidable heights.
• Another challenge was reducing the corrosion of the steel rebar supporting the predominantly concrete structure to achieve the 100 year design life of the building.
• The foundations, pile-caps and basements had to be waterproofed as well.
Product used: BASF's Glenium SKY 504 concrete admixture could offer the required early strengths as well as workability retention at ambient temperatures of above 45° C in a mix to be pumped to a height of at least 660 m using a single pump at ground level. Glenium SKY hyperplasticiser enabled 100 mpa working on a water cement ratio of 0.24 (ie, a high cementitious content). BASF's 2-mm Masterpren BG geomembrane with high mechanical characteristics, coupled with Geotextiles (SNW 40 & 50) and W4 Waterstops, completed the waterproofing system. Masterflex 900 re-injectable hoses and Masterflex 610S re-wellable gaskets were also installed in the construction joints to provide a maintenance solution for the future. Also, Masterflow 410 Plus epoxy grouts were used to encompass the pile heads and sandwich the waterproofing membrane.
Relevance to India: "Being part of the Burj Khalifa was a privilege for BASF Construction Chemicals," says Upen Patel, Business Director, BASF India Ltd. "We are happy that the range of construction chemicals used for this project is available in India. We are entertaining a fair number of inquiries for the construction of tall buildings in Mumbai, mandating the pumping of concrete to heights of 250 m. Similar technologies in a singular nature are being used for tall building construction projects here. India has gained from having engineers working on the Burj Khalifa project, many of whom acquired know-how about these chemicals and relocated to India with this knowledge after its completion."
Challenges in the Indian context: "While the Burj Khalifa is situated in an area that is accessible from all four sides, most tall buildings being constructed in India, mostly in Mumbai, are situated in congested localities. Hence, maximum material deliveries must take place during lean traffic hours. Compare this to the scene in Dubai, where 5,000 cu m of concrete was consumed once in a 24-hour cycle, necessitating 400 trucks to deliver material at the site. Application is not a challenge as we have certified applicators whose services are strongly recommended. BASF is also particular about offering clients technical supervision to ensure the best outcomes."

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