Mixing waste – whether used coffee grounds or recycled soft plastics – into concrete and keeping it out of landfill is a way one of the world’s most-used building materials can boost a circular economy and consume less virgin material such as sand.

The carbon content of concrete, one of the highest-emitting materials, can also be cut by using alternative binding agents such as slag from molten metal, treated contaminated soil or flyash from coal-fired powerstations instead of cement.