Light-emitting cement

Dr José Carlos Rubio, from Mexico’s University of San Nicolas Hidalgo, has created a light-emitting cement that has a life span of 100 years. By absorbing solar energy and returning it to the environment, Dr Rubio says the material will be able to light roads, highways and bicycle lanes without the need for electricity.

“Nine years ago, when I started the project, I realised there was nothing similar worldwide, and so I started to work on it,” said Dr Rubio. “The main issue was that cement is an opaque body that doesn’t allow the [passing] of light to its interior.”

Dr Rubio explained that common cement is a dust that, when added to water, dissolves as an effervescent pill. “In that moment,” he said, “it starts to become a gel” — similar to the kind used for hair styling, but stronger and more resistant. At the same time, some crystal flakes are formed — these are unwanted subproducts in hardened cement.

Because of this, Dr Rubio focused on modifying the microstructure of the cement in order to eliminate crystals and make it completely gel, helping it to absorb solar energy and then return it to the environment as light. The idea is that the building, road, highway or structure that’s made out of the cement will begin to absorb solar light in the morning and emit it for around 12 hours during the night.

Dr Rubio noted that most fluorescent materials are made out of plastic and have an average life span of three years because they decay with UV rays. The new cement, on the other hand, is made out of sand, dust or clay, which becomes the gel, and the only residue is water. It is also sun-resistant and has an estimated life span of 100 years.

The material currently exists in the colours blue and green, while the light intensity can be regulated to avoid dazzling drivers or cyclists. Its inclusion in plaster and other construction products is also being developed.