The Topmix Permeable concrete works by having a permeable layer on the surface, made up of relatively large pebbles through which water can drain almost instantly. This is followed by an ‘attenuation layer’, which feeds the water into a drainage system that connects with the city’s groundwater reservoirs.

Therefore all the water is being fed straight back into the system for irrigation, drinking water, swimming pools, and firefighting purposes.

While permeable concrete has been around for the past 50 years, it’s mostly been used under pavements to help with drainage, so the researchers at Tarmac designed a surface layer version of it that’s capable of withstanding the weight of heavy traffic.

Not only can the super-absorbent concrete be used in conjunction with existing concrete - cities can install it so the runoff from regular concrete is fed into the Topmix Permeable - but it will also be significantly cooler than regular concrete during the hottest months of the year. “During periods of rising temperatures and intense rainfall, water stored within the system evaporates creating a cooling effect reducing surface temperatures,” Tarmac said.

If that water happens to freeze, the entire system would be destroyed, so the concrete can only be used in places where temperatures are never likely to dip that low.