Concrete is all around you – in the foundation of your home, the bridges you drive over, the sidewalks and buildings of cities. It is often described as the second-most used material by volume on Earth after water.

But the way concrete is made today also makes it a major contributor to climate change.

Portland cement, the key component of concrete, is responsible for about 8% of global greenhouse gas emissions. That’s because it’s made by heating limestone to high temperatures, a process that burns a large amount of fossil fuels for energy and releases carbon dioxide from the limestone in the process.

The good news is that there are alternatives, and they are gaining attention.

Cementlike substances have been used in construction for thousands of years. Architects have found evidence of their use in the pyramids of Egypt and the buildings and aqueducts of the Roman Empire.

The Portland cement commonly used in construction today was patented in 1824 by Joseph Aspdin, a British bricklayer.

Modern cement preparation starts with crushing the excavated raw materials limestone and clay and then heating them in a kiln at around 2,650 degrees Fahrenheit (about 1,450 degrees Celsius) to form clinker, a hard, rocklike residue. The clinker is then cooled and ground with gypsum into a fine powder, which is called cement.

About 40% of the carbon dioxide emissions from cement production come from burning fossil fuels to generate the high heat needed to run the kiln. The rest come as the heat converts limestone (calcium carbonate) to lime (calcium oxide), releasing carbon dioxide.

In all, between half a ton and 1 ton of greenhouse gas is released per ton of Portland cement. Cement is a binding agent that, mixed with water, holds........

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