Small Cement Mixture Change Could Reduce GHG Emissions

cement-mixture
Bryan Kilgore for Zondits, October 3, 2014

Cement is produced with mixtures of calcium rich minerals and clay. The targeted industry standard mixture ratio of calcium to clay is 1.7. The mixture is cooked at high temperatures reaching 1,500°C (2,732°F). Carbon dioxide emissions are produced due to chemical reactions involved and heating energy required. MIT researchers, led by Roland Pellenq, discovered that a small mixture ratio adjustment to 1.5 could reduce CO2 emissions during cement production up to 60% and increased mechanical resistance to fractures.

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MIT’s new cement recipe could cut carbon emissions by more than half

Gizmag, September 28, 2014

As one of our most relied upon construction materials, concrete makes a significant contribution to our overall carbon emissions. Calcium-based substances are heated at high temperatures to form the cement, a process that produces carbon dioxide. But by slightly altering the quantities of materials used, scientists from MIT have uncovered a new method of cement mixing that could reduce these emissions by more than half.

Concrete is generally made by mixing gravel, water, sand and cement. To produce the cement, calcium-rich materials such as limestone are cooked up, typically with clay, at temperatures as high as 1,500° C (2,732° F). The energy required to heat up the mix combined with a resultant chemical reaction generates carbon dioxide, a process the researchers say is responsible for between five and ten percent of total industrial greenhouse gas emissions.

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