Crystals are key when it comes to reducing cement’s carbon footprint

Published on October 4th, 2016 | By: Stephanie Liverani

[Image above] Credit: whereareyousimon; Flickr CC BY 2.0

From infrastructure to automobiles to electricity, our manufacturing processes and the ways we consume energy are getting “greener.”

And the goal is clear: reduce carbon emissions.

The U.S. Environmental Protection Agency is developing stringent standards to reduce emissions, and this week India formally joined the Paris climate change agreement by officially adding the country to the list of United Nations members to ratify the plan.

But the challenge remains when it comes to transforming how we manufacture one of the most ubiquitous construction materials on the planet—cement.

Current cement manufacturing practices are carbon-intensive. In fact, today’s standard Portland cement production accounts for nearly 5% of the world’s total carbon emissions, so researchers are looking to nature for solutions to more sustainable concrete production.

In April, researchers from Rice University in Houston, Texas, took an atomic-level look at how concrete is produced. Rouzbeh Shahsavari, theoretical physicist at Rice, and his team published the results of computer modeling studies that reveal how dislocations—or screw-like defects—in raw crystals used for concrete affect manufacturing efficiency.

They found that tricalcium silicates (C3S) that consist of pure rhombohedral crystals are better than others for producing cement clinker—round lumps of C3S that, when ground into a powder, mix with water to make cement. When a clinker is easy to grind, manufacturers don’t need to work as hard, the team explained in a press release.

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