This Cement absorbs CO2 like a sponge

http://www.pbs.org/newshour/bb/cement-alternative-absorbs-carbon-dioxide-like-sponge/

Cement has been called the foundation of modern civilization, the stuff of highways, bridges, sidewalks and buildings of all sizes. But its production comes with a huge carbon footprint. Environmental chemist David Stone was seeking a way to keep iron from rusting when he stumbled upon a possible substitute that requires significantly less energy. Special correspondent Kathleen McCleery reports.