Reducing CO2 Emissions with Concrete

For the past few weeks builders have been working hard to create a new toilet/shower block facility for the camp I am working at in Hanmer Springs, New Zealand. Today they did the deed of pouring concrete for the foundation of the new building, competing against the morning frost that lay thick on the ground. As they went through the grueling process of leveling out the concrete, it got me thinking of a home renovation television show I had seen once where a couple chose to make their home as green as possible, right down to the cement they chose. Using limestone, they were able to create a home they could be proud of given for its eco-friendly qualities.

This brought about the thought of concrete and how something that is so widely used in our world – it “is the second most used material in the world after water” (Garcia, 2010) – could be affecting our environment. I’ve only ever thought of concrete as a solid mixture of rock and not much more than that. After doing some research on the topic I’ve found that first off, cement and concrete are not the same thing. Cement is one ingredient that binds together with rock when water is added. When it all hardens, that is what becomes concrete.

Now, using water and rock to create concrete isn’t so much of an environmental issue as what cement is. Standard cement, commonly known as Portland cement, is a “mixture of processed limestone, shales, and clays which contain the following compounds: CaO (lime), Al2O3 (Alumina),SiO2 (silica) and iron oxides” (What is Concrete?, 2011). Of course, the properties of cement can vary in every situation as the relative amounts of each compound are not exact. And it is within these properties that there is cause for environmental concern. The processing alone to create such a product screams CO2 emission wastage.

But there is hope in the world today within the world of concrete. Researchers from the UK and India are in the process of experimenting with the properties of Portland cement in order to figure out if there is a greener solution to what currently exists. The theory is to replace “the ingredients of Portland cement with waste materials, [hoping] to reduce cement’s carbon footprint. The researchers are using waste materials such as fly ash acquired from burning coals, slag from iron works and even rice husks” (Garcia, 2010).

The idea is going further in green thinking by considering not only the process of how cement is created, but the fact that as more and more cement is being used for creating concrete – our world’s natural resources of limestone and other such elements are rapidly depleting. This research initiative will take five years to complete and hopes to provide inspiration on how to decrease emissions as cement currently contributes to 5% of the world’s CO2 emissions.

Above and beyond research projects, there are companies currently providing a greener cement for use in many on-going construction projects around the world. Take Ecocem, a Green Awards 2011 sponsor and an Irish entrepreneurial company as a prime example. “Ecocem produces GGBS cement, a superior cement with many technical, environmental and architectural advantages (www.ecocem.ie). Since commencing production Ecocem has saved over 3 million tones of CO2 and will be saving over 1 million tones of CO2 on an annual basis going forward” (Green Awards 2011 Sponsors, 2011).

This is a critical point to take note of as with climate change, those with the greatest influence must have the biggest concern for our environment to be a better place. As stated by Ecocem, “if an individual in their normal life reduced their emissions by 50% they might save 8 tonnes of CO2 anually,” but “if professionals in the construction industry reduce the emissions of their projects during construction by 50% they can save up to 4,000,000 tonnes of CO2 annually” (Overview – National Climate Change Strategy, 2011).

In taking on this statistic, Ecocem has developed an environmentally friendly cement that can (and has been) used in education, health, retail, water, wastewater, local authority, housing and farming projects in the European regions of Holland, Ireland and France. In doing this, Ecocem has figured that if half the cement used in a year was of a green cement such as GGBS, then 2,000,000 tonnes of CO2 would be reduced. On a more personal level, should you decide to go green with your cement while building your new home, there’s a potential of saving over 10 tonnes of CO2 within that single project which would be the “equivalent of leaving your car at home for over 2 years” (Overview – National Climate Change Strategy, 2011).

With all that overload of information, it can be easy to see how making the investment for your next building project to include green cement for your concrete would be beneficial.

In reading up more on Ecocem, you’ll find the argument quite clear that there is no need to worry about sacrificing the technical components that make concrete so strong when choosing a green cement. Concrete made with green cement is just as strong, if not stronger.

Limestone or reusing waste materials are just two examples of how cement can become more environmentally friendly – and it doesn’t just stop with the ingredients. Concrete as a building material on a whole can be considered a “green” element to a construction site. “Concrete acts as a natural insulator, or better said, helps to adjust to environmental conditions” (Eco-Concrete: A Green Building Material, 2011). Not quite like a good quality merino sweater, but close enough. Concrete helps a homeowner’s heating/cooling needs by retaining heat. This means that during the cold winter days it absorbs the sun’s warmth, whereas in the summer it helps to keep the air cool. Most of all, concrete is an excellent building tool as it tends to be completely airtight, eliminating the worry that energy is being wasted by seeping out through cracks in the wall.

Because concrete is usually of a lighter color, it reflects light, making it a beneficial material when building in an environment where many buildings are placed closely together. Quite simply, a material that is colored to absorb light can increase the area’s overall temperature – not a great situation for muggy summer afternoons.

According to Eco-Concrete: A Green Building Material (2011), the feature of concrete that best exhibits its ability to be a sustainable product is its durability. “Sustainable building and living emphasizes long-term solutions and products over cheap, short-term products that will be thrown away and add to the waste management issues that already exist. Concrete can last for many times longer than conventional building materials, such as wood or drywall. It is very resistant to common causes of deterioration in homes such as insect activity, rot, rust and even fire” (Eco-Concrete: A Green Building Material, 2011).

Overall, sometimes going green means getting back to the basics. They say the most important feature of a building is its foundation. Imagine what our world would be like if the foundation of all our buildings were designed with being green in mind.

Imagine a world in which we could dramatically decrease our CO2 emissions with each construction project?

Companies such as Ecocem have gotten the ball rolling – all that is left is for us to jump aboard and join in the ride.

Bibliography

Eco-Concrete: A Green Building Material. (2011). Retrieved July 2, 2011, from Concrete Ideas: http://www.concreteideas.com/eco-concrete-a-green-building-material

Garcia, H. (2010, April 20). British and Indian Experts Experiment with Portland Cement for a Greener Concrete. Retrieved July 2, 2011, from Aggregate Research: http://www.aggregateresearch.com/articles/18990/British-and-Indian-experts-experiment-with-Portland-Cement-for-a-greener-concrete-.aspx

Green Awards 2011 Sponsors. (2011). Retrieved July 2, 2011, from Green Awards: http://www.greenawards.ie/sponsors.php

Overview – National Climate Change Strategy. (2011). Retrieved July 2, 2011, from Ecocem: http://www.ecocem.ie/index.php?p=environmental

What is Concrete? (2011). Retrieved July 2, 2011, from Sim Science: http://www.simscience.org/cracks/advanced/concrete2.html

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