Concrete — a mixture of cement, sand, and water — is the second most used material on Earth after water. Ton-for-ton, more of it is laid down every year than steel, wood, plastics, and aluminium combined. Problem is, cement production emits 8% of global CO2 — four times that of air travel. Swedish startup Cemvision has devised a cement making process that utilises by-products from industries like steel and mining instead of fresh limestone, resulting in a circular, cleaner alternative.  “We’re on track to producing cement that emits 95% less carbon than traditional methods while remaining just as strong and…This story continues at The Next Web