Concrete is the most-used artificial material. The concrete industry is vast and it is estimated that around seven per cent of CO2 emissions come from the manufacture and use of cement (the main component of concrete) alone. A large proportion of this is due to the use of calcium, which is normally obtained by burning limestone and which is essential for the reaction between cement and water to form concrete.
Considerable research efforts are already underway to find alternative ways of making concrete or similar construction materials more sustainable.
Now, the University of Tokyo researchers have demonstrated a method for combining waste concrete and captured CO2 to create a usable form of concrete called calcium carbonate concrete.
Inspired by the way some aquatic organisms harden into fossils over time, Professor Ippei Maruyama wondered if the same process for forming hard calcium carbonate deposits from dead organic matter could be applied to concrete...