Cement is a material that is all around us and one that we hardly notice. It is the main ingredient in concrete, which is in the bridges we cross, the sidewalks we step on and the buildings we work in. Cement is the second most consumed material on Earth, only behind water. More surprising than the amount we consume is the amount of CO2 that cement produces. This single industry can make up anywhere between 5% to 10% of global emissions.
The main substance in cement is limestone that is heated to 1400C and then ground down to create a lumpy, yet solid substance known as clinker. Clinker is them combined with gypsum to form cement. The amount of heat needed to produce cement makes its energy and emission consumption very high. The heating of limestone creates CO2 as does the burning of fossil fuels to heat the kiln. The most common cement used for construction is Portland cement, which is the cheapest and consequently has the most environmental concerns.
Researchers at the Ecole Polytechnique Federal de Lausanne (EFPL) in Switzerland believe they have found a more efficient way to create cement. Their cement is produced by materials that are widely used and available- calcined clay and ground limestone. By mixing in their cement, known as LC3, with Portland cement, they believe they can bring down global CO2 emissions by several percent. It is not enough to just cut emissions, the new cement must also be strong and durable enough to be used as current cement is.
The EFPL just received a round of funding to further their research and we here at Coburn-Myers are looking forward to what they come up with.