Climate-Friendly Cement Could Pave the Way to a Cooler Future

There’s one sneaky contributor to carbon dioxide emissions that very few people acknowledge, and we stand on it every day: cement. However, in recent years, new companies have been designing environmentally friendly options to manufacture this city-loved material, which now accounts for a twelfth of global CO2 emissions.

It’s projected by the United States Department of Agriculture that, by the year 2050, urban land coverage in the US will grow from 3.1% to a total of 8.1%. Because of this rapid urban growth, thousands of trees and ecosystems will be paved away to create new parking lots and apartment complexes, and due to this, cement companies are incentivized to manufacture billions of gallons of cement every year.

The Creation Process

Not only does cement choke habitats and entomb fertile soil, but the process that’s used to make cement is far from sustainable. The most common way to manufacture cement is through a dry method. The first step is to quarry the principal raw materials, mainly limestone, and then crush the rock in multiple stages. The first crushing reduces the rock to a maximum size of about 6 inches, and then again to about 3 inches or smaller. The crushed rock is combined with other ingredients such as iron ore or fly ash and ground, mixed, and fed to a cement kiln. The cement kiln heats all the ingredients to about 2,700 degrees Fahrenheit in huge cylindrical steel rotary kilns lined with special firebrick. 

After this, Portland Cement Association, while explaining this process in an article, kindly noted that, “As the material moves through the kiln, certain elements are driven off in the form of gasses.” What they fail to assess is that these “certain elements” refer to the carbon dioxide and natural gasses released into our atmosphere, and it’s not a small amount. The environment will continue to be polluted with over 4 billion tonnes of carbon dioxide annually due to this industry. Yet since concrete is such a widespread material, the industry continues to grow. 

Cement is found in everything from concrete, roofs, to structures for healthcare, education, energy, and more. But its benefits mask enormous dangers to the planet and to human health. In fact, The Guardian notes that, “If the cement industry were a country, it would be the third largest carbon dioxide emitter in the world, surpassed only by China and the US.” However, this isn’t just up to one country to fix this problem, but rather, a global challenge. 

Finding Solutions

While it’s impossible to ever stop the manufacturing of cement, other eco-friendly options are being designed as we speak. At the moment, there are very few carbon-negative cements on the market since manufacturers can be wary of the quality and sturdiness these eco-materials may lack. This is why Brimstone, a 35-person startup in Cleveland, Ohio, broke boundaries by receiving certification through a third-party that their cement is structurally and chemically the same as regular cement.

These materials have the same quality and performance that builders have used for over 150 years, but with a key difference: on net, their process removes carbon dioxide out of the air instead of putting it in, making Brimstone’s cement carbon-negative. 

Instead of baking limestone which releases Co2, it starts with carbon-free silicate rock. Brimstone commissioned Twining Consulting, an engineering firm, to help test its alternative cement — analyzing its air contents, measuring its setting time, compressing cubes of the stuff to test its strength. The result: Brimstone’s product met one of the most commonly used standards in the business, known as ASTM C150.

Despite the fact that Brimstone has engineered their cement, they are still far away from obtaining the support and resources in order to start selling. Compared to the emissions produced by vehicles or from power plants, cement still remains of little interest to the public. However, through recent publicity and the combination of a large donation of 500,000 from the federal government’s Advanced Research Projects Agency-Energy, and investors including Amazon’s Climate Pledge Fund and Bill Gates-founded Breakthrough Energy Ventures, we can only hope that our gray, concrete world may become slightly greener.