The Dirty Business of Cement Gets a Clean Up from MIT
By James Quirk
Is it possible to change how the most ubiquitous building material on earth is made — one so dirty that it accounts for nearly a tenth of greenhouse gases, yet so cheap to produce that it costs less per kilogram than bottled water?
Researchers at MIT think so. They describe in the journal PNAS a new process for making cement without emitting greenhouse gases.
Cement manufacturing is a dirty business, achieved by grinding up limestone, which is then typically cooked using coal at high heat with sand and clay. As the underlying ingredient in concrete, cement accounts for 8% of global greenhouse gas emissions. If cement were its own country, it would be the third-highest greenhouse gas emitter. For every kilogram of cement produced, an equal amount of carbon dioxide is released into the atmosphere.
Business is booming: the annual growth rate of cement production is 2.5%, with 3.6 billion metric tons produced per year, according to Utpal Nandy, managing director of BU Builders and Consultants, a development company based in India.
Photo courtesy of Martin Reisch.