This pavement is lit.
A team of scientists at Michoacan University in Mexico have created a type of cement that glows in the dark. Roads made with this material would be able to light up highways and bike paths without the use of electricity, purely by absorbing energy from the sun’s rays. Similarly, buildings and other structures constructed with this concrete coating would be illuminated as well.
To create cement with this property, scientists modified its microstructure so it wouldn’t form crystals. In that way, the new concrete is more like glass, allowing light to penetrate the material, as opposed to more typical, opaque concrete. Scientists achieved these optical properties by mixing standard raw materials with other additives; in the end, it became phosphorescent in the dark.
Berta Carreño, writing for Scientific American, explains:
Phosphorescent materials absorb energy from radiation such as the ultraviolet light emitted by the sun—or by lamps, if indoors—energy they later emit as light, which can be seen after dark. As it loads up energetically with ultraviolet rays, even on cloudy days the cement will be able to absorb enough energy to glow during dark periods for up to 12 hours.
The team still needs to optimize the balance of materials in order to regulate its luminescent intensity and color. A phosphorescent concrete that’s too bright would pose a hazard to late-night drivers.
This newly-developed concrete isn’t ready for the marketplace yet and it will need to be further studied to understand the material’s new properties. For example, its inorganic nature may pose new questions about the stability of its compounds and how to perform repairs.
These self-lit roads, could be particularly beneficial in areas with limited access to electricity, Carmen Andrade, a researcher at the Spanish National Research Council Institute of Building Sciences in Madrid, told Scientific American.
The announcement of luminous concrete comes on the heels of the recently published atlas on light pollution, which reveals that a third of humanity can no longer see the Milky Way. It’s possible that these roads could one day replace street lights, potentially reducing this light pollution. But, depending on their luminance, they could alternately add to the mass of artificial light that obscures the stars.