Green Geopolymer Concrete Cuts Carbon Emissions and Endures 800°C

Traditional Portland cement production accounts for about 7‑8% of global CO₂ emissions, with the process requiring high‑temperature kilns that emit roughly 0.6 ton of CO₂ per ton of cement. China produces about half of the world’s cement, while the sector’s overall carbon intensity has changed little since the 19th‑century invention of Portland cement.

Researchers at Kaunas University of Technology in Lithuania have developed a geopolymer mortar made entirely from industrial and construction waste, including recycled ceramic bricks and metakaolin from a glass factory. The binder is activated with an alkaline solution, avoiding energy‑intensive kilns. Laboratory tests showed that after exposure to 800 °C, the best mixes retained compressive strengths up to 53 MPa with limited cracking, outperforming conventional concrete, which typically loses strength at such temperatures. The material is suited for high‑heat applications such as tunnels, industrial plants, chimneys, and furnaces. Professor Danutė Vaičiukynienė highlighted the potential for this waste‑based binder to reduce the cement sector’s carbon footprint, while energy expert Vaclav Smil underscored the broader challenge of decarbonising steel, concrete, plastics and fertilizers.