Concrete, a Centuries-Old Material, Gets a New Recipe

https://www.nytimes.com/2020/08/11/business/concrete-cement-manufacturing-green-emissions.html

Source:  By Jane Margolies, The New York Times. 

Excerpt: ...Central [Concrete] — one of a handful of companies at the forefront of a movement to make a greener concrete — is increasingly experimenting with some decidedly new mixtures. In one part of the plant, carbon dioxide from a chemical gas company is injected into the concrete, locking in that greenhouse gas and keeping it out of the atmosphere, where it would contribute to global warming. Elsewhere, engineers tinker with the recipe for concrete, trying out substitutes for some of the cement, which makes up about 15 percent of the mix and functions as the glue that holds it all together. Cement, however, is also responsible for most of concrete’s carbon emissions — emissions so high that some have abandoned concrete for alternative building materials like mass timber and bamboo. ...concrete is also responsible for about 8 percent of global carbon emissions. If concrete were a country, it would rank third in emissions behind China and the United States. ...Central, part of U.S. Concrete, a manufacturer based in Texas, is making progress tackling the problem: Low-emission concrete makes up 70 percent of the material the company produces annually, up from 20 percent in the early 2000s....