Analysis: Concrete is the most used construction material in the world and makes up around 5% of Ireland's emissions
Cement and concrete are amazing. Yes, you have read that right. Combined, they form the basis for all infrastructure around us from our homes to the roads, bridges and tunnels we drive on, to airports, stadiums and train stations. The recently constructed 3D concrete printed house in Dundalk demonstrates the advancement in technology and material science that concrete is making to our infrastructure.
Next to water, concrete is the most consumed material in the world and has been in use for thousands of years. The earliest use of concrete dates to 7,000 BC. The Romans used concrete to construct awe-inspiring structures like the Pantheon and aqueducts, which are still in use today. In 1894, Joseph Aspdin invented the traditional 'Portland' cement which revolutionised concrete production.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
From RTÉ 1's Nine News, Dundalk homeowner says moving into the 3D printed home is like 'winning the lottery'
But while concrete provides us with so much, it comes with a price: its environmental impact, principally through carbon emissions. Concrete contributes approximately 5% of Ireland's carbon emissions and and 8% at a global level mostly through the production of the cement used to bind it together.
Before I go on, let me clarify something that is often misunderstood: cement and concrete are not the same thing. Cement is a powder and one of the constituents that goes into concrete. Concrete comprises of cement and water that glues the other main constituents, namely sand and stone (known as aggregates) to form the rigid strong material that we all know.
Cement is the grey powder manufactured in cement factories. In Ireland, we have three manufacturers with plants around the country. If you get an opportunity to visit a cement factory, take it. The sheer size of the plant and scale of the process is only surpassed by the nature of the science underlying its production.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
From RTÉ Radio 1's Today with Claire Byrne, UCD physicist Dr Shane Bergin on the secret history of concrete
In essence, cement is essentially limestone rock mixed with clay and shale which is ground into a powder and heated to over 1,4000C in a kiln. The change from limestone to cement at these temperatures creates 'clinker' which is ground with gypsum to a fine powder. Due to the underlying chemistry, you can't make cement without releasing carbon dioxide.
Irish manufacturers are aware of the environmental impact of their product and have invested in producing cement in a more sustainable and energy efficient way. To reduce the carbon load in concrete, designers and specifiers regularly substitute cement with other ‘supplemental cementitious materials’ as they are called. These are often waste materials from other industrial process so using them has a double benefit as they would otherwise be landfilled.
The most common supplemental material used in Ireland is a waste product from iron manufacture. This low carbon white coloured 'slag' is ground down into a fine powder and added to concrete, replacing between 30 and 70% of the cement, depending on the application. Other by-product materials like fly-ash, from coal combustion and silica fume from silica production are also substituted for cement in concrete. In more recent years, processed clays (a type of soil) have been used in conjunction with limestone and gypsum to make concrete. Geopolymer concretes, often with no Portland cement, are also gaining traction due to their low carbon footprint.
We need your consent to load this rte-player contentWe use rte-player to manage extra content that can set cookies on your device and collect data about your activity. Please review their details and accept them to load the content.Manage Preferences
From RTÉ Archives, Peter McNiff visits a Cork theme park where animals from across the globe are sculpted in cement for a 1976 episode of Newsround
While Ireland doesn’t have iron manufacture or silica production industries, it does have a large reserve of fly-ash and bottom ash at the ESB generation facility at Moneypoint in Co. Clare. The coal-burning operation at Moneypoint has now stopped, but the byproduct still remains. Ireland also has some limited amounts of suitable clays that could be used as a cement replacement.
Another material that has shown potential, is powdered recycled glass that can be blended with slags and cement to create a lower carbon cement. Researchers at Trinity College Dublin have recently transformed biomass ash byproduct taken from the Edenderry Power Station into a high-quality, low carbon concrete. Another area of interest is the recycling of old concrete as fresh aggregate and the use of filtered rainwater. All of these can further reduce concrete’s environmental impact and support Ireland’s drive for greener construction.
Concrete and cement are central to infrastructure and will continue to form an integral part of all our lives.
Research is underway at TU Dublin in collaboration with the construction industry to investigate the potential of Irish materials to lower the carbon impact of concrete. This work is timely considering the Government's Cement and Concrete Decarbonisation Working Group has highlighted an urgent need to explore and develop low carbon concrete in the medium to long term.
Concrete and cement are central to infrastructure and will continue to form an integral part of all our lives. Collaboration between industry, academia and government is stronger than ever, and green public procurement policies are driving demand for a lower carbon and sustainable practical and scalable product. With the right investment and public awareness, concrete can be part of the climate solution. The story of cement, concrete and carbon is one of opportunity. Every bridge, school and home built with lower-carbon concrete brings us closer to more sustainable world for thousands of years to come.
Follow RTÉ Brainstorm on WhatsApp and Instagram for more stories and updates
The views expressed here are those of the author and do not represent or reflect the views of RTÉ
