11 great green ideas

It's a concrete world and the production of cement, a key component of concrete, is a huge source of greenhouse gas emissions. And because concrete is often sealed with a waterproof chemical membrane, it is difficult to recycle. Carlstadt, N.J.-based Hycrete replaces that membrane with a waterproof solution that is mixed into the concrete itself. That allows concrete to be recycled, thus cutting down on cement production. But CEO David Rosenberg's sales pitch is as much about economics as the environment -- Hycrete, he stresses, saves contractors time and money. -- Ryan Derousseau

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