I will admit it, I am too lazy to read the entire thing as I am pretty skeptical. Where are they getting the hydroxide from? Does cured concrete contain significant amounts of unreacted calcium hydroxide and they are essentially suggesting to finish curing the concrete after the structures have been demolished and ground up for recycling? It also seems that this would at best absorb the carbon released during the initial cement production and even there only the fraction released from the carbonate but not the fraction used for heating.