Construction

Industry calls for ‘commitment-free’ concrete

For each ton of concrete produced, one ton of carbon dioxide is emitted; yet despite the race to provide alternatives, analysts say the Middle East industry is not ready for change — unless it is made easy

It is no secret the construction industry is responsible for more waste and pollution than any other sector in the world. Not only do poorly-designed buildings contribute to 50% of the world’s carbon-dioxide (CO2) emissions, some reports claim that concrete alone is responsible for up to 10% of these emissions, due in part to energy-intensive production methods.

Of all the resources and materials in the world, the cement used to manufacture concrete is the second most consumed substance after water. According to research by French manufacturer Lafarge, every year almost one ton of concrete is produced for every human on the planet, with each ton of concrete generating around a ton of CO2.

Yet in the face of these statistics, technology analyst Lux Research claims the industry’s low CO2 alternatives “have a poor shot at gaining support” in the region.

According to the firm’s recently-published paper ‘Paving the way to cost, energy and carbon savings in the concrete industry’, the only alternatives which will gain industry support are those which require the least commitment from manufacturers and users.

“New technologies must be commercially viable,” remarks Oliver Tassinari, who is the author of the report.

“Low CO2 alternative materials to Portland cement will have a poor shot at gaining support. They remain largely unproven at scale and carry substantial economic risks due to the capital cost requirements for production. Other barriers like demonstrating the new material’s performance within ASTM International guidelines remain as well,” he adds.

Yet in light of higher standards, which aim to reduce waste and pollution in the industry, more alternatives are entering the market to meet a variety of demands.

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CO2 Reductions

30%

Al Falah says its ready mix substitute can reduce the level of CO2 impact by up to 30%

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“The really important factors when specifying materials are the design itself, the awareness of the designers and the suitability of the material. Our company philosophy is to provide those involved in the design process with the information they need to specify the right, sustainable material for that project,” explains Pejman Norastehfar, head of the Middle East region for Bayer MaterialScience.

Lack of buy-in

The only alternatives advocated in the report are those which “require the least commitment from manufacturers”, including heat recovery during the manufacturing process and increasing the use of industrial wastes such as fly-ash, silica fume, rice hull ash and slag.

The environmental benefits are still significant; heat recovery allows captured energy to be used in other processes and the use and re-use of industrial wastes prevents such materials going to landfill. Measures like these can potentially reduce energy consumption by up to 65% and CO2 emissions by 60%.

“Nowadays, there are many products under development such as geo-polymers with complete cement replacements.

“The common supplementary cementitious material such as GGBS, Silica Fume and Fly Ash remain the prominent materials at hand,” says Rabih Fakih, managing director of Dubaibased Grey Matters Group.

“However, cost feasibility and practicality of usage is still not being rationalised,” he adds.

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Dangerous Designs

50%

Reports claims poorly-designed buildings contribute to 50% of global CO2 emissions

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But whether the chances of gaining support are poor or otherwise, a market for alternative products does exist and is beginning to gain credibility worldwide.

Manufacturer Al Falah has developed a substitute, branded as Ready Mix, which reduces the CO2 impact of cement by up to 30% compared to standard concrete. Currently under development at Masdar City in Abu Dhabi, Ready Mix uses less cement, a component of concrete, while retaining its standard features, such as durability and strength. It was announced in 2009 that two million m3 of Ready Mix will be used in the construction of the initial phases of Masdar City.

So far, green concrete has not been adopted generally by designers as they consider the premium cost compared to conventional concrete is still unjustified“

“Low-carbon concrete is a relatively new concept in the construction industry and it is vital that we continue to explore and invest in new technologies that will help minimise the industry’s impact on the environment,” Al Falah chairman Zayed Falah Bin Jarra says.

Others such as foam concrete, which unlike Portland-based materials provides both strength and thermal insulation, reduce the carbon impact of production and increase the efficiency of the finished building.

Standard concrete is made from calciumbased chemical compounds, which require high temperatures to bond; a number of companies are in the process of developing magnesium-based materials, which are twice as strong, therefore requiring lighter application. Some versions even claim to reduce the levels of CO2 in their surrounding atmosphere.

Other alternatives use aluminium-based compounds, which can be produced at “ambient” temperatures, while another trend is seeing a return to natural lime-based cement, popular with the ancient Egyptians, Romans and Greeks, and only replaced when mass-manufactured alternatives emerged in the mid-20th Century.

Where it is not possible to reduce the impact of the concrete, it may be possible to offset the impact via carbon capture techniques. Developed by California-based scientific researcher Calera, the Calera Process uses the CO2 emitted from power plants to manufacture the cement destined for use in concrete.

The process captures the carbon dioxide produced from flue gas and converts it into stable solid minerals; effectively recycling 90% of the CO2 emitted by the plants.

According to Calera, use of the technology means that coal and natural gas plants can potentially have a lower carbon footprint than solar power. It’s a process the company says has “huge potential”.

A testimonial from the US Green Building Council reads: “It’s like planting forests of trees through the pouring of concrete or bricks. I have never seen anything with the potential that Calera has.”

Building on progress

Despite the production process, of all the materials in the world, concrete is not the environment’s worst enemy and its properties have made it one of the world’s most highlydemanded construction materials.

It is durable, versatile, long lasting and can be easily broken down and reformed. It is produced on site, removing the need for transport and the demand on natural resources such as wood.

Once manufactured, it produces no emissions, needs no toxic preservatives and is fire resistant.

Yet it is these very points which make the alternatives appear risky. In its report, Lux Research states that green materials are “largely unproven and require substantial capital investment”, factors which even a robust economy cannot ignore.

“So far, green concrete has not been adopted generally by designers as they consider the premium cost compared to conventional concrete is still unjustified.

“In addition, real estate developers see no high return on investment if additional capital is being invested on green concrete. All of these parameters are strengthened by a lack of legislation and incentives from the government,” comments Fakih.

Yet, he concludes that in time attitudes will change.

“Once environmental awareness gains more support, the popularity of green concrete will rapidly increase in the construction culture.”

About Concrete

-Concrete is an aggregate material made with a combination of rocks, sand and gravel, held together with Portland cement glue

-The glue is produced by heating limestone and clay to temperatures of around 3000°F, a process which emits a ton of carbon per ton of concrete

-Worldwide, concrete is used twice as much as any other building material and the cement mix which forms it is the second most consumed substance on the planet after water

-While alternatives to concrete’s energy-intensive production methods do exist, adoption rates are low

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