When rising temperatures make air conditioning a costly necessity, this new cement might just be the solution you’ve been looking for. Developed by researchers at Southeast University in China and published in Science Advances, this specially engineered cement doesn’t simply absorb the sun’s heat—it reflects it. By skilfully incorporating reflective ettringite crystals into its mix, the cement acts like both a mirror and a radiator, bringing down indoor temperatures even under intense sunlight.
If you’ve ever struggled with high energy bills or uncomfortable indoor heat, then you’ll appreciate how straightforward this innovation is. The process is simple yet effective: minerals such as limestone and gypsum are ground into a fine powder, mixed with water, and cast into a silicon mould equipped with small holes. These holes allow the ettringite crystals to form directly on the surface, setting the stage for the cement’s cooling properties. Tests on a Purdue University rooftop showed the material to be 5.4°C cooler than the surrounding air, even under peak sunlight.
The cement’s benefits don’t stop at temperature control. It also boasts rapid setting properties—enough to resist the impact of a 200g iron ball from a short distance within six minutes. Moreover, rigorous mechanical and environmental tests have been passed with flying colours, and machine learning analysis suggests that, over the course of 70 years, this material could yield a net-negative carbon footprint. In other words, it might well help steer the cement industry towards becoming a leader in carbon reduction.
With buildings consuming nearly 40% of global energy and contributing to about 36% of carbon emissions, innovations like this are essential. This supercool cement not only promises a reduction in energy use and lower bills, but it also paves the way for healthier, cooler urban environments. As we look to build a more sustainable future, small changes at the construction level can make a significant impact.
