Roughly 5 to 10 percent of global CO2 emissions are related to the manufacture and transportation of cement, a major ingredient of concrete. With cement production expected to grow exponentially in coming decades, the industry is trying to address its environmental challenges.

The manufacture of cement is relatively efficient when compared with other building materials, such as steel and wood. The problem is the scale at which it’s produced – roughly 2.4 billion tons in 2006 and growing.

Worldwide, manufacturers are experimenting with using organic waste materials as a substitute for some of the cement used in concrete. These materials can replace up to 25 percent of the cement in the mix. Less cement means less greenhouse gas produced. Italy’s Italcemente is the world’s fifth-largest cement producer, and it is looking beyond reducing CO2 emissions by creating a cement that actually breaks down airborne pollutants.

No easy replacement for cement is on the horizon. No other known material is as abundant, accessible, and effective as limestone, the key ingredient in cement.

Read (Christian Science Monitor)