Cement’s carbon footprint, and alternatives we can use
The worldwide cement market is booming due to the demands of urban construction, but the massive levels of carbon it uses has been fuelling research into environmentally-friendly alternatives to cement.
It’s a little-known fact that cement is one of the most environmentally-damaging products used in construction, and while its impact is not as obvious as that of fossil fuels, cement production is a significant contributor to global carbon emissions, accounting for approximately 5% of the carbon released into the atmosphere every year. With the world finally beginning to take carbon emissions seriously, there is increasing pressure on industry to reduce carbon footprints, leading to notable opportunities for environmentally-friendly solutions.
Capital Concrete is the first company in the UK to supply Earth-friendly, cement-free concrete, significantly reducing the carbon impact, by up to 79% compared to traditional concrete. And there is no difference in the performance, so for us – and many of our clients, this is a no-brainer, with very little by way of cost differential.
AshCrete is another concrete alternative, using fly ash instead of traditional cement. Fly ash is a by-product of burning coal, and 97% of the traditional constituents in concrete could be replaced with materials that have been recycled.
We also try to use locally-sourced materials to minimise the impact of transportation, and we take great care to recycle any materials we can, and try to keep the disposal of non-recyclable materials to a minimum.
The science behind cement and carbon emissions
To make cement, limestone (calcium carbonate) and clay are heated up inside a large kiln. The heat releases carbon dioxide from the limestone and converts it to lime (calcium oxide) which then reacts with the silica in the clay to form alite and belite, both of which are calcium silicates. Cement is used as a bonding agent when combined with gravel to create concrete.
Removing carbon dioxide from limestone is a vital part of the process of making cement but that carbon dioxide is then released into the air, contributing to global emissions. What’s more, the cement making process requires burning fossil fuels for the running of industrial ovens, as well as the mining and transporting of raw materials and more that adds to cement’s carbon footprint.
Reducing the amount of carbon dioxide that we are pumping into the air is a matter of critical importance , and every industry needs to find ways to refine its practices to achieve carbon neutrality as quickly as possible. The cement industry is a key example, leading the way in pursuit of eco-friendly alternatives to cement. As the literal building blocks of civilization, we can’t reduce the amount of cement needed to improve the lives of people all over the world, but we can come up with innovative solutions for smarter concrete.
We are grateful to Joseph Keller for some elements of the scientific information used in this article, taking from an article that appeared in Agriculture Investing News in March 2019