ACC-Concrete_100 m

ACC INTRODUCES SELF-COMPACTING CONCRETE M 100

ACC Concrete Limited has introduced an innovative concrete solution, M–100 grade, which is specially designed for the construction of high intensity towers in India. The specialized concrete solution is a one stop shop offered by ACC Concrete for high strength and performance of vertical Hi towers in the country.

Insufficient availability of land is leading to subsequent scaling land prices in mega cities like Mumbai. To build up tall and high intensity concrete skyscrapers–availability of right specialised Ready Mix Concrete (RMX) solutions is the most critical thing for builders in India.

ACC-Concrete_100 m

ACC-Concrete_100 m

Witnessing an upcoming trend of vertical high towers in India, ACC Concrete organized a live demonstration seminar of pumping special Hi Tower Concrete at ACC Thane complex near Mumbai. The demo-seminar showcased the process of pumping the special grade of concrete and the display of self compacting and temperature controlled & ‘M–100 grade of concrete’ over 300 metres. ACC customers and major builders across the city attended the seminar and discussed the potential of using specialized concrete solutions for the upcoming high rises in the city, the company said.

HansFuchs, managing director, ACC Concrete Limited said, “ACC’s expertise in RMX is backed by 100 years of global expertise from Holcim and 75 years of indigenous experience of ACC in India. Today, vertical growth is seen as the only solution to meet the growing demand for space in metros in India. In Mumbai alone 128 towers with height more than 300 feet are planned to come up in next 3-4 years while 75 towers of height more than 300 feet already exist. Concrete Pumping to such heights requires special mix of desired RMX grades in which ACC concrete specializes.”

The company said this concrete attains a high compressive strength of 100 MPa (1 MPa equivalent to 1 Newton force/ mm2) after 28 days. With the introduction of M-100 grade, ACC Concrete has become the only ready mix concrete company in India to offer specialized solutions for high intensity towers in the country. “This was for the first time in India that M100 RMX was pumped over length of 300m and for the first time in world that M100 was manufactured without natural sand but using only manufactured fine aggregates,” it added.

ACC Concrete is one of the largest manufacturers of Ready Mix Concrete in India with over 51 modern plants in major cities such as Mumbai, Bangalore, Kolkata, Chennai, Delhi, Hyderabad, Goa, Chandigarh and Ahmedabad.

Kandhal mix

GETTING THE RIGHT MIX

A simple, cost-effective solution is available for repairing roads. Why are contractors and government development agencies turning a blind eye?
BY IMRAN MIRZA
If you visit Jaipur during monsoon, one thing that you would unmistakably end up noticing is the quality of roads. Unlike Mumbai and most other metros — where the first few showers turn the roads into a sea of potholes of all shapes and sizes — the roads in Jaipur are smooth as a runway. So what has Jaipur done that other cities have been unable to do?

The Jaipur Development Authority (JDA) has been using a readymade, generic, cold bituminous patching mix technology during monsoon, since 2010. The agency has done patch repairs worth more than Rs1 crore with great success. The authority has to maintain over 6,000-km lane of roads and streets in and around Jaipur, which receives an annual rainfall of around 650mm. Witnessing the success of this technology, even the Rajasthan PWD has followed JDA’s lead and used the same cold mix all across Rajasthan during 2012 monsoon.

There is no standard readymade cold patching material available in India, which can be used during the rainy season when hot mix plants are usually shut down. It is difficult to design stockpile patching mixtures because the properties required in stockpiling and handling, and after the material is placed in the pothole are contradictory. Some of these contradictory requirements pertain to aggregate gradation, aggregate shape and binder viscosity.

Kandhal mix

A new, unpatented, generic cold mix (Kandhal mix) promises pothole-free roads for years.

So what is this generic, unpatented, readymade cold bituminous mix technology? While working in Pennsylvania, USA, as chief asphalt engineer, Professor Prithvi Singh Kandhal, developed a simple and effective cold bituminous mix for potholes during early 1980s. This cold patching mix is manufactured in a batch type hot mix plant using local aggregates. The mix can be placed without preparing the pothole such as drying, squaring the edges, cleaning, and tack coating. This mix can be used to fill potholes during the rainy season, even when they are wet. The ‘idiot proof’ mix, as Kandhal calls it, requires no preparation of the pothole.
In a nationwide US Strategic Highway Research Program (SHRP) field study, this mix was adjudged as number  one in terms of its durability in potholes. About 78 per cent of the patches survived for over four years. It has been used in extreme cold and rainy weather in the US for over 30 years. This readymade cold mix can be made and stored for six months and can be made by any bituminous mix plant (portable or stationary) in India using local materials. The mix has been successfully tried on Jaipur streets and on the Jaipur-Agra Road with the help of the students and faculty of Malviya National Institute of Technology in Jaipur and IJM. It also has been tried successfully by the West Bengal PWD and IIT Guwahati.
Kandhal argues that this cold mix technology is as cost effective as hot mix. “Cost analyses have shown that the cost of repairing potholes with readymade cold mix is about the same as cost of repairing with hot mix because the latter is more labour, material (tack coat), and equipment (roller) intensive,” he points out. Contractors struggle with using hot mix technology during rainy season as the roads are wet, leaving the mix ineffective.
Potholes get larger and deeper during the three months of monsoon and, therefore, require much more hot mix, the cost of prompt repair of potholes with cold mix may be half of hot mix. “What is the cost of injuries and fatalities; vehicle repair costs; and user delays resulting from unfilled potholes?” questions Kandhal. “It is very hard to estimate these costs. If we are a civilised country, we simply cannot wait and repair potholes after monsoon ends as we have been doing for the last 65 years after independence,” he stresses.
The mix is also handy for contractors who are responsible for maintaining national highways, state highways or PMGSY roads during the concession or warranty period. If there are a few potholes, there is no need to arrange hot mix. The contractor can take some bags of this mix, a labourer and a hand rammer, in a car or a pickup, and get the potholes repaired, as and when required. There is no need to wait for a sizeable number of potholes to appear and then fix them, as is in the case of hot mix.
Contractors and engineers often cite the lack of Indian Roads Congress (IRC) or MoRTH specifications for readymade cold patching mix for not using this technology. “This is again a lame excuse,” says Kandhal. The specifications prepared for this mix have been adopted by the JDA and Rajasthan PWD. Moreover, many contractors are already using patented readymade cold mix made with foreign technology, and are paying a premium price for it.
Kandhal had submitted a draft of this cold mix to the Flexible Pavement Committee of IRC for approval more than two years ago, but there has been no progress on this front. Construction Week received no response from the IRC, despite repeated emails asking for the status of this paper. Kandhal’s attempts to get the Central Road Research Institute (CRRI) to test the mix in its labs have received no response, highlighting the callousness of these institutions towards matters of public interest.
JDA’s engineer, Sapan Mishra, shared his experience with the mix. “We tried it first on a few patches. It has worked really well for us. The road adjacent to the potholes has come off but the potholes haven’t appeared again.” Mishra advises that it’s important to get the recipe of the mix right. “The aggregates, gradation and bitumen should be used based on the local conditions,” says Mishra. Jaipur has taken the lead and has invited tenders to use repair roads using this cold mix. “The response has been good. We are receiving lower-priced bids than we did earlier,” Mishra revealed, indicating that contractors have realised the benefits of economies of scale.
“This proposed generic mix is less than half the price of those patented mixes. Why are they paying more when this mix can be made by a local contractor,” asks Kandhal. The 72-year-old professor is willing to offer voluntary technical assistance and knowhow to those who are willing to try the technology. “With the availability of this mix, there is no excuse to use 19th century technology for filling potholes. We have the specifications; cost analyses; success story of this mix in Jaipur — essentially, everything you need for calling tenders. Do we still have an excuse?” scoffs Kandhal.

Construction-Chemicals

READY FOR A CONSTRUCTIVE ROLE

India’s construction industry that is growing at the rate of 30% annually makes a good case for rapid growth of construction chemical sector. Though the industry has not been in the forefront to adopt chemicals as integral part of construction, much due to lack of awareness, the situation, however, slowly but steadily improving. With all the emphasis is now on infrastructure development which has opened up new opportunities for big construction companies including foreign ones, the demand for construction chemicals is surly going to grow manifold.
“The Construction Chemicals industry has grown up steadily in last decade due to relatively include awareness as well as entry of several companies to India. The construction chemical industry has come up to age in our country,” says Samir Surlaker, Managing Director, MC-Bauchemie (India) Pvt. Ltd.

Construction-Chemicals

Construction-Chemicals

As the country is witnessing huge project developments, the sectors like power, roads, and housing besides others are going to fuel demand for construction chemicals. “The sectors that would be fuelling the growth would be basically infrastructure and housing. There is a huge demand for power, transportation and housing in India which would continue to have an effect on the industrial growth,” says DS Ramachandra, Marketing Manager, Construction Systems, BASF India Ltd.
According to some estimate, the market size of India’s construction chemicals industry is Rs1700-1800 crore, with potential to see growth rate of 20-25% per annum. “It has potential to grow to Rs5000 crore if the industry promotes itself professionally and increases the level of awareness of construction industry. The construction industry should be convinced that usage of construction chemicals is a benefit and not undue cost,” says Surlaker.
Construction chemicals can broadly be categorized into five groups–concrete and mortar admixtures; water proofing compounds; floor hardeners; protective coatings and resins; and adhesives and sealants.
Being a developing country, Ramachandra says, still lot of new construction is going to take place to meet huge demands coming from various industries. “Hence most widely used construction chemical would be admixtures, be it for the sake of workability or waterproofing. Obviously, the other chemicals that are bound to gain importance would be waterproofing,” he adds.
Dow Corning’s Commercial Manager for the construction industry in India and South Asia, CRG Prasad agrees: “The most widely-used and accepted construction chemicals used in India are admixtures, curing compounds, water repellents, cement additives and grouts.”
Of these, he says, Dow Corning’s expertise in the construction chemical market is specifically with regards to water repellents and cement additives. The US-based company looks to expand its share in this rapidly growing market. “We aim to increase awareness of the benefits of construction chemicals based on our innovative silicone technologies, and are focusing on our existing product range that is available globally,” Prasad adds.

Construction_Week_November_2013

HOW TO SPOT BAD CONSTRUCTION IN BUILDINGS

Two building collapses have received a great deal of media coverage thus far in 2013: the building collapse in Thane, Mumbai and Savar, Bangladesh. Whereas 74 people lost their lives in the Thane building collapse, the death toll was more than 700 in the Savar building collapse.

In the South Asian cities that are witnessing rapid urbanisation, building collapses are a common phenomenon, but these tragedies seem to mostly occur in small buildings belonging to low income and informal and semi-formal neighbourhoods. In fact, it is quite possible that the total toll caused by such collapses could be higher compared to the large-scale ones that happen occasionally.

These collapses do not necessarily occur because the buildings are illegally constructed. Gaps in the system lead to poor quality of construction. Further, multi-floor structures are constructed by untrained workers without proper engineering knowledge.

Often, generic reasons such as use of substandard materials and poor construction are attributed to building collapses without conducting any proper investigations.The aim of this article is to provide some information as to how you can spot bad construction.

#1: Constructing buildings, especially high-rise buildings, without performing proper soil analysis can cause cracks on the structure as well as on the outside pavement.

Types of foundation problems can include windows and doors that make noise, jam or separate from frames, cracks that appear near the corners of windows and doors as well as at wall joints, cracks in basement that continue to widen or cause water seepage and leaky roofs.

#2: The use of defective building material can cause construction defects. For example, water leakage caused by defective material can weaken the structure.

Defects in construction and use of bad construction material can be spotted by looking for presence of moisture, mold and mildew in buildings.

#3: The vertical or horizontal cracks on plastered walls indicate shrinkage and drying and are normal. Cracks that are jagged, resemble stair steps and are at 45 degrees generally point to settling issues and structural movement.
These cracks are usually harmless, but can be serious sometimes. A crack that is less than 1/8th of an inch width is usually caused because of stress and is considered to be harmless. However, a crack that is 1/4th of inch or more wide is more serious.

In the case of concrete walls, vertical as well as diagonal cracks typically signify foundation movement. If the vertical crack widens at the bottom or top, it may be because of settling or gradual heaving. Stair-step cracks also indicate heaving. Horizontal cracks signify design defects or build up of pressure behind the wall. Horizontal cracks can cause serious problems. Design aspects are compromised and people who do not have adequate technical knowledge related to construction of buildings are frequently entrusted with the multi-floor building projects.

Finally, the rising cost of land and building materials drives people, especially those living on low incomes, to seek cheaper options. In Indian cities, this invariably means being at the mercy of fly-by-night developers with no reputations to protect. This is regrettable, because many reputed developers have projects in various price-bands. In other words, a lower price does not have to mean dangerously low construction quality.

Infosys-Pocharam-Hyderabad-118

AFFORDABLE SUSTAINABILITY

Green development does not necessarily mean extra cost. Proper planning and right construction practices can actually bring down the project cost. 

India’s sustainable quotient has grown substantially over the last decade or so, but the country still has a long way to go. With green responsiveness still restricted to a handful of large-sized construction companies, there is a need to spread sustainable building practices across various levels of the industry.

While most developers still look at green as a unique feature or selling proposition, some have made it an integral aspect of their properties. Unlike residential properties where, once built, the onus is on the users to make the most of the building’s green design, in commercial and self-use buildings, the owners have to consider the operational costs a well. This makes it important to have sustainable buildings that are environment as well as budget-friendly.

Often, developers restrain themselves from getting into green construction, fearing that higher capital cost will dent the project viability.This, along with the fact that besides being able to charge a premium for green projects, there’s not much incentive for developers to go green. However, contrary to this popular belief, there are a number of sustainable practices that not only help reduce cost but also offer long-term benefits in the form of savings in energy and water usage.

Infosys-Pocharam-Hyderabad-118

Infosys-Pocharam-Hyderabad

For example, developers can look at adopting some easy but cost-effective construction practices to construct sustainable buildings. Major cost in construction comes from the structural materials such as brick, steel, glass, cladding, tiles and ceiling materials. Rumi Engineer, business head, Godrej Green Building Consultancy Services, points out that since materials play a very significant role in construction, it’s critical to select them based on their cost, reliability and life-cycle factors. “To have an energy-efficient structure, one must look at the thermal insulation properties of the material used. For bricks, which are extensively used in all types of constructions, builders can use AAC (Autoclaved Aerated Concrete) blocks and fly-ash concrete,” he says.

Another important criterion for selecting the materials is their availability in local proximity. “Transporting material from miles away from project site will not only add to the cost but also have environmental impact. GRIHA/IGBC Green rating systems encourage selecting materials, which are available locally, and have recycled content and good thermal resistance properties. This proposition adds value to the project and does not have an impact on the overall project cost,” Engineer adds.

Here, we look at some unique materials, designs and technologies that can help developers up their green quotient, without spending a great deal of money.

Radiant cooling technology

Although radiant cooling technology has been around since long, not many developers have used it for commercial buildings. This, despite the fact that a radiant cooling system is easier to install as it requires fewer equipment and the overall cost of the system is also slightly lower than conventional air-conditioning systems.

Infosys was the first commercial building in India to install the radiant cooling technology at its software development Block-1 at Pocharam campus in Hyderabad. The most significant feature of the building is that it is split into two symmetric halves. One half is cooled by conventional air-conditioning and the other half by radiant cooling.

Since there are different seasons in Hyderabad, the project is a good example to demonstrate that radiant cooling is effective even in tropical climates. Also, the system consumes 33 per cent less energy compared to conventional air-conditioning system. These are among the lowest numbers for energy consumption in an office building globally. It provides better indoor air quality and thermal comfort, compared to conventional air-conditioning.

The most important aspect for developers while implementing any new technology is the capital cost involved. In case of radiant cooling, it was found that the capital cost of the system is slightly lower than conventional air-conditioning.

In addition to radiant cooling, the platinum-rated Infosys building has put in place an efficient envelope for better orientation, double walls with insulation, insulated roof and windows with appropriate shading to maximise natural light in the building and minimise heat ingress. The property is about 40 per cent more efficient than ASHRAE baseline. The building has been equipped with energy meters for each equipment of the air-conditioning system as well as radiant cooling system. It also features a building automation system to monitor and control the operation of the building systems accurately.

The project has also been given 5- star ratings by GRIHA.

Renewable energy

The benefits of renewable energy—both in terms of environmental as well as savings in energy cost are not unknown to anyone. But many developers wonder whether this technology is viable for their projects; whether it can be used for commercial buildings; what’s the payback period, and so on.

With government subsidy already in place, it makes good business sense to opt for renewable sources of energy—such as wind and solar—to meet energy needs. Solar and wind energy plants need not have to be on the project site. The wind farm can be located hundreds of miles away from the project site, which can be linked to the power-grid and supply power to the project. It is possible to meet 100 per cent of the electricity requirements through wind energy. ITC Grand Chola in Chennai, a 5-star GRIHA rated and the world’s largest LEED platinum green hotel has implemented such a system. The five-star property owns a wind farm of 12.6 MW capacity that caters to 100 per cent of its electricity requirements. The wind farm generates 27,90,0000 KWh units of electricity annually.

Besides wind energy, solar energy can also be tapped to reduce a project’s carbon footprint. One such example is the administrative building of Pimpri Chinchwad New Town Development Authority (PCNTDA) in Pune. Since the building is a government office and not a profit centre, it was imperative for developers to keep the operation costs to the minimum. The GRIHA 5 star-rated project has a 100 KWp solar PV system installed at the site. The low energy footprint and the attractive subsidy offered by the government for rooftop solar PV systems prompted the owner and the design team to consider using solar PV. The solar panel generates 1,45,985 kWh, which meets 86 per cent of building’s energy requirements. At present, the building has 65 per cent occupancy and the entire energy requirement—including space conditioning, process equipment, lifts, pumps, and day and night time artificial lighting—is met by solar power. The ITC Grand Chola hotel also uses solar concentrators to meet 25 per cent of the domestic hot water requirement.

Since the climate is quite comfortable in Pune, the developer of PCNTDA decided to avoid air-conditioning and opted for natural ventilation to enhance indoor thermal comfort by means of solar passive design.

Pre-engineered buildings

For setting-up a green manufacturing plant, pre-engineered building (PEB) could be the best bet. Since PEBs use 100 per cent steel, which is recyclable up to 90 per cent, it saves primary resources and reduces waste. Such buildings are quick to erect, thereby offering savings in labour and construction cost. Tata Motors’ Dharwad plant is a good example of this. The shop buildings were mostly pre-engineered, which was necessary keeping in mind the deadline for commissioning the plant. Interarch, which was given the contract, had to implement various green features for the manufacturing facility, keeping the IGBC norms under consideration.

The buildings have been designed to use maximum day light (and not heat) which ensures that power consumption for non-process lighting is nil. This was achieved by providing translucent polycarbonate sheets in roofing and cladding. Further, to save time, site roll forming for entire roofing, cladding and liner was done, and more than 72,000 sq. m of roofing and cladding was executed. Window canopies were also fitted to modify the SHGC of window glass. The building also has built windows without canopies that provide lighting as per prescribed SHGC factors. The use of green glass ensures that there is minimal heat gain inside the building.

Other features include use of LED for street lighting, shop general lighting, installing 17kWp hybrid solar and wind power systems to power offices. Interarch installed 4 per cent skylights on the roof of the total roof area of the building and 4 per cent in wall, which reduces the need of artificial lights inside the building and saves electricity.

The plant’s maximum daily water requirement of 2,550 cu.m., was met by taking various water conservation measures. A lake was created for storage of water, which can be processed for further use, besides having reverse osmosis treatment for water recycling.

Interarch also had to implement many innovative solutions like highest safety standards, followed in line with international standard and TML guidelines, to achieve zero accident, logistic and warehousing control at site to meet site standard norms. The plant has already received IGBC’s LEED platinum certification.

Retrofitting for existing buildings

It’s much easier to incorporate sustainable features in new construction as compared to existing building. Besides in-depth understanding of the operations, meticulous planning and execution schemes also need to be rolled out for management to accept the retrofit project.

While it’s a challenging task, scientific planning and analysis of energy consumption can give a clear idea about areas for improvement.

An example of retrofitting could be the 40-year old Godrej Bhavan in south Mumbai. This is the first building in Mumbai and the sixth building in India to have receive the LEED Gold certification from the USGBC under the existing buildings operations and maintenance category.

The project completed its retrofitting in 2010 and within two years it has started to see the benefits in terms of cost and energy savings. The project is on track to recover the costs of installing energy-efficiency measures through lower electricity bills. There has been a reduction in energy usage from 5,94,696 kWh (2009-10) to 5,27,160 kWh (2010-11) to 5,21,856 (2011-12).

The project basically focused on three aspects: HVAC, lighting, and the building maintenance system, that account for the bulk of the energy savings. The upgraded HVAC system captures the maximum savings of the measures installed, accounting for an average of 32 per cent in the overall electricity savings for FY 2010-12.

As is evident from the examples discussed here, going green is not always a costly affair. What is required is efficient planning and designing at the initial stage itself. While the awareness is very much visible at the commercial sector, it’s imperative that developers expand their horizons and do more of residential green buildings. Although it’s worth mentioning that India is not doing badly either when it comes to green building footprint. According to IGBC, India’s green building footprint is 1.4 billion sq. ft — second only to the US.

However, there is a need to have a holistic approach towards sustainability, which must not be restricted to only gaining some points to attain green certification.

Top 10 ways to go green

Rumi Engineer, business head, Godrej Green Building Consultancy Services list down key points developers should keep in mind for attaining green certification.

1. Building envelope materials: Use AAC/concrete blocks with fly-ash content to reduce heat load inside a building.

2. Water use reduction: Use low-flow plumbing fixtures to reduce water wastage. Install sewage treatment plant for recycling of water.

3. Waste management: Install organic waste converters within your premises. The manure collected could be used for gardening purposes.

4. Energy efficiency: Install BEE 5-star rated light fixtures, LEDs and electrical devices such as pumps, motors and water heaters.

5. Rain water harvesting: You can either recharge the ground by installing percolation pits or store the rain water in tanks for flushing and cleaning purposes.

6. Alternate energy usage: By installing small solar or wind power systems, you can take care of smaller electrical loads and water heating.

7. Building design: The emphasis should be on using maximum day lighting but taking care of glare. As per the climatic condition, one can design natural ventilation wherever applicable.

8. Green house gas reduction: Source all building materials locally to minimise transportation.

9. Reduction of heat island effect: Though China Mosaic is an age-old proven methodology to reflect back the heat, one can apply high albedo paint on the roof.

10. Erosion & sedimentation control: Install pits to arrest soil particles/ sediments.

Rukki

ACC LAUNCHES INTEGRATED RAPID CONCRETE SOLUTIONS

ACC Concrete has recently introduced two new solutions— UTWT 24 and Speedcrete—for instant road surface overlay and repair in India. UTWT 24 and Speedcrete are high performance overlays laid in depth ranging from 100mm – 150 mm for road sections in India. Designed as complete solutions from study of raw materials, UTWT 24 and Speedcrete allow roads to be trafficked within 24 hours and eight hours respectively from the time of application.

ACC-concrete-mixer-laying

ACC-concrete-mixer-laying

ACC Concrete launched both the solutions through a live demonstration of overlaying at ACC Thane complex near Mumbai. The demo-seminar showcased the process of how UTWT 24 and Speedcrete can speed up the overlay of pavement within highly accelerated time.

Hans Fuchs, managing director, ACC Concrete said, “Every year crores of rupees are spent on road maintenance and filling potholes across cities in India. Speedcrete is an integrated high performing novel solution from ACC Concrete for planned instant road repairs. A delivery of Speedcrete is treated with utmost care and completed by experienced personnel with special techniques before trafficking in eight hours.”

UTWT 24 and Speedcrete are integrated solutions comprising of amorphous materials and contain cement, modified polymers, mineral and chemical admixtures that help in quickly achieving desired properties of concrete. They are produced under strict control and formulation; delivered in a controlled manner and craftsmanship on placing, finishing, curing etc by specialists and experienced personnel. They are designed as a complete solution from study of raw materials to finish overlay at application site to speed up the overlay of pavement. The solutions can be put to multiple applications ranging from urban roads & highways repairs, road rehabilitations & repairs, air pavement repairs, bridge deck repairs to loading dock & ports repairs.