This is one of those questions that can’t be satisfied by a simple yes or no. Concrete is essential for building so it would be impractical to put a blanket veto on concrete. The concrete isn’t necessarily bad; it’s more the process of manufacturing concrete (the second biggest greenhouse gas emitter) – for every ton of cement that is produced, one ton of CO2 is released.
How is it Made?
The process of making concrete is a dabble of science. Firstly, limestone (calcium carbonate), and feedstock materials like clay, are heated to the staggering temperature of 10,000 degrees C. When the limestone hits those temperatures, it breaks down into Calcium Oxide (lime), Silicon Oxides, and Carbon Dioxide. The two oxides are mixed together to make di & tri-calcium Silicate – ground into a fine powder called clinker. Gypsum is added to the clinker to prevent instant setting. Breaking down the limestone accounts for 70% of the CO2 release, burning fossil fuels accounts for only 30%.
The easy solution would be to just stop producing concrete but there are so many vital businesses that rely on it. For example, concrete is the ideal material for patios, driveways, and other areas of hardstanding – you can find more information about the benefits on richfieldconcrete.com.
However, different production methods could make the process greener and more suitable for the environment of today.
Solar Power
The kilns used to heat the clay and limestone reach extremely high temperatures. Traditionally, this has been achieved by burning fossil fuels (accounting for 30% of the total carbon dioxide released during the process). By simply making a switch to a greener heating source, we can eliminate this. For example, using a focused solar power plant could achieve the heat levels without releasing the CO2.
Extra Strong Concrete
Without going into too much detail on this one, the basic idea is that by changing the feedstock (the clay, etc.) entering the furnace, then the chemical composition of the clinker would be changed. An extra strong concrete would mean less is needed to have the same impact. Plasticizers are additives that can be added to the concrete to increase its strength.
Electrolysis
Electrolysis, the process of passing an electric current through a liquid solution, has been developed by MIT scientists for the making of concrete. The idea is that if electrolysis is carried out under 8000 degrees C, the lime would be produced alongside Oxygen and Carbon Monoxide – which can be sold as fuel to use plastics. The process might still generate a dangerous chemical, but it carries the two birds with one stone effect.
The Takeaway
We could have gone into a lot more detail here about whether concrete is bad for the environment, but that would have called for a lot more coffee and time. However, we now have a basic understanding and can safely say that concrete as a finished product is not bad for the environment – but the process of manufacturing concrete can be quite malicious on our ozone layer. Hopefully, in years to come, we can find a way to make concrete without its carbon footprint.
