Overview

• A Science Advances study from Southeast University reports a metasurface-enhanced cement that kept its surface 5.4°C below ambient air and 26°C below Portland cement in rooftop tests at Purdue University.
• The material grows reflective ettringite crystals in engineered surface depressions and uses an aluminum‑rich gel to transmit infrared, achieving about 96.2% solar reflectance and 96% mid‑infrared emissivity.
• Researchers describe scalable, lower‑temperature manufacturing that they say makes the cement roughly $5 per tonne cheaper than conventional Portland cement.
• Mechanical, environmental, and optical durability tests are reported, and the mix showed very fast early stiffness development, withstanding a 200 g ball drop after six minutes of hydration.
• The team’s machine‑learning analysis suggests potential net‑negative carbon impact over 70 years, though outside experts caution that surface cooling does not guarantee real‑world air or interior temperature reductions without further field validation.