Concrete is one of the building products that have literally transformed our world. With the addition of steel reinforcing, this amazing product allows humans to create structures that reach to amazing heights and vast expanses. The only problem: the heating of limestone required for the production of Portland cement (the binder in concrete) produces significant amounts of carbon dioxide. According to environmental scientists, that is a problem. Can concrete become more environmentally friendly? According to Chris Keenan at Green Building Elements, one California entrepreneur may have found the answer.
Our hope may lie with Brent Constantz and his California company Calera. Calera is creating cement that actually reduces the amount of CO2 put into the air by power plants. Their location, across the street from a major Californian power plant, siphons smoke stack emissions from the power plant, runs the gas through oil rig or brackish water, and the salts and minerals from the water bond with the carbon dioxide in the gas to precipitate out limestone in much the same way that mother nature does it. What he gets is cement, hard aggregate for making concrete, and water that is already a step toward being purified for drinking thus reducing the time and energy needed to return it to a potable state. The cement can be used just like Portland cement, for new buildings or even just patch jobs.