Researchers have turned concrete from a demolished school building and carbon dioxide (CO2) from the air into new blocks strong enough to build a house with. The process involved grinding the old concrete into powder, reacting it with CO2 from the air, pressurizing it in layers in a mold and finally heating it to form the new block. Instead of making buildings from new concrete only, this technique could offer a way to recycle old materials while also trapping carbon dioxide in the process. The blocks could theoretically be remade again and again, through the same process.
