Researchers from the University of São Paulo and Princeton University have developed a groundbreaking method to recycle cement waste into a sustainable, low-carbon alternative that performs comparably to conventional cement.

This innovative recycling process could potentially reduce emissions from the cement industry by up to 61%, far exceeding the Global Cement and Concrete Association's estimated 9% reduction through traditional clinker replacement methods.

The new technique involves heating crushed concrete to 500 °C, effectively restoring its binder properties without generating harmful emissions.

Their study, published in ACS Sustainable Chemistry & Engineering, demonstrates that mixtures containing up to 80% recycled cement can match the strength of traditional Portland cement while significantly lowering carbon emissions.

By blending recycled cement with finely ground Portland cement or limestone, the resulting mix achieves industry-standard strength and workability, addressing previous performance issues associated with solely using recycled materials.

This technology promotes a circular carbon economy by allowing materials from demolished structures to be reused in new construction projects.

Research leader Sérgio Angulo emphasized that construction waste is often relegated to landfills or low-grade applications, making their recycling approach a significant breakthrough for high-quality applications.

The partnership between Angulo and White aims to address the durability and long-term use of the recycled cement, contributing to a more sustainable future in construction.

Despite the promising technology, challenges remain for wider adoption, including the need for improved sorting and processing of demolition waste and updates to building codes to support performance-based standards.

In Brazil, the implementation of performance-based standards for non-structural building applications may encourage the use of recycled cements.

The collaboration between Angulo and White began when Angulo was a visiting researcher at Princeton in 2023, enhancing their research capabilities and perspectives.

With Portland cement responsible for about 8% of global emissions, reducing its carbon intensity is a crucial goal for the cement industry.