It’s the stuff of modern life, and we use it in astonishing quantities. Last year, around the world, nearly two billion tons of steel was produced — more than 500 pounds for every person on earth. And at least 30 billion tons of concrete, or nearly 9,000 pounds for each of us. The scale can be hard to believe, until you look at a runway or a suspension bridge and contemplate what was required to build it.
Apart from developing blended cements, researchers and companies are focusing on ways to use captured CO2 as an ingredient in the concrete itself, locking it away and preventing it from entering the atmosphere. CO2 can be added in the form of aggregates — or injected during mixing. Carbonation curing, also known as CO2 curing, can also be used after concrete has been cast.
You may have come across the detectable warnings on sidewalk ramps before crossing the street. They're called truncated domes, which are surface indicators designed to assist those who are visually impaired, like Rachel Fisher.
In a typical year, more than 50 blind runners complete the California International Marathon with guides; 53 runners who identified themselves as having a vision impairment finished the New York City Marathon in 2019. Many others ran shorter races.