Mixing Up Greener Cement
Oakland, CA — You don't have to look far to see just how much concrete humans use. Everything from highways to high-rise and bridges to runways around the world are made with the energy-intensive, carbon-spewing material.
Contributing at least 5 percent of global carbon dioxide (CO2) emissions, the cement industry is ripe for changes to lower its impact. Cement, the glue that binds concrete, is one of the most carbon-intensive materials out there: It produces one ton of CO2 for every ton of cement made.
The main culprit responsible for the industry's emissions is Portland cement, the most commonly used type of cement, which is created through an energy-intensive process of crushing raw materials and heating them to up to 3,000 degrees Fahrenheit.
Many companies are reducing the amount of Portland cement needed in concrete by replacing some of it with fly ash, a byproduct of coal-fired power plants. In addition to eliminating some of the emissions and raw materials associated with Portland cement, fly ash makes concrete stronger and easier to work with.
Article continues: http://www.greenbiz.com/news/2009/11/12/companies-mixing-up-greener-cement
PHOTO CREDIT: CALSTAR PRODUCTS