The construction industry is one of the largest in the world, and cement and concrete are literally the building blocks of its success. Evolving from prehistoric caves to today’s towering skyscrapers, concrete structures have and will continue to be vital components of modern civilization, providing long-lasting, reliable support for buildings, roads, bridges, tunnels and dams. So much so that concrete is the most consumed material on Earth, second only to water, while the steel used to reinforce it is by far the most commonly used metal. But this doesn’t come without high environmental costs: concrete accounts for 8% of global CO2 emissions, much of which come from the extraction and transportation of aggregate materials such as sand, gravel and crushed stone.