Recycled Cements Drive Down Emissions Without Slacking on Strength

Typography

Giving a second life to construction materials after demolition, engineers at the University of São Paulo and Princeton have developed an approach for recycling cement waste into a sustainable, low-carbon alternative that is comparable in performance to the industry standard.

Giving a second life to construction materials after demolition, engineers at the University of São Paulo and Princeton have developed an approach for recycling cement waste into a sustainable, low-carbon alternative that is comparable in performance to the industry standard.

In addition to lowering the carbon intensity of the cement and concrete industry, the process could enable new uses for construction and demolition waste, of which concrete is a significant component. In 2018 in the United States, the total amount of construction and demolition waste was more than twice that of household waste.

“Construction waste typically ends up either in a landfill, or, if it’s recycled, will be used in low-grade applications such as in pavements or in soils,” said research leader Sérgio Angulo, a professor of Civil and Urban Construction Engineering at the University of São Paulo. “It’s exciting to show that we can, in fact, recycle this recovered cement waste into a high-quality application.”

Read More: Princeton University, Engineering School

A comparison of recycled cement by itself (left), ordinary Portland cement (middle), and the researchers’ optimized blend of recycled cement and finely ground Portland cement (right), before the addition of water. The optimized cement blend demonstrates similar water requirements, strength gain, and workability to ordinary Portland cement while generating a fraction of the carbon emissions. (Photo Credit: first author Mateus Zanovello, a Ph.D. student working with Angulo at the University of São Paulo).