Concrete Is Most Used Material

From the sidewalks beneath our feet to the towering dams that power our cities, modern civilization is quite literally built on a foundation (Review) of concrete. Its global use is staggering, second only to water as the most-consumed substance on the planet. But what we call concrete is actually a composite material. It's a carefully balanced recipe of aggregate (crushed stone, gravel, and sand) that is bound together by a paste made of water and cement. When these ingredients are mixed, a chemical reaction called hydration begins, causing the mixture to harden and gain its formidable, rock-like strength.

While we often think of it as a modern invention, the basic concept is ancient. The Romans were masters of an early form of concrete, using volcanic ash to create structures so durable that many, like the iconic dome of the Pantheon, still stand today. The key innovation that sparked its modern ubiquity was the invention of Portland cement in the 19th century. This new binder was stronger and more consistent, turning concrete into the affordable, versatile, and reliable building material that enabled the construction boom of the last 150 years.

This incredible utility, however, comes with a significant environmental cost. The production of Portland cement is an energy-intensive process that involves heating limestone to extreme temperatures, which releases vast amounts of carbon dioxide. As a result, the cement industry is a major contributor to global greenhouse gas emissions. This has spurred a worldwide race among scientists and engineers to develop greener, more sustainable alternatives that can meet our insatiable demand for concrete without the heavy carbon footprint.