Concrete is rarely the most fascinating of subjects, but a strange ‘thirsty’ version of the material has turned it into something rather compelling.
Topmix Permeable concrete is designed to be a super-absorbent surface covering that allows water to seep through it rather than sitting on top in an attempt to combat flooding.
A video of the material being tested in a car park shows the concrete ‘drinking’ 880 gallons (4,000 litres) of water in around a minute, with most of it disappearing almost as soon as it hits the ground.
It works by having a permeable layer of concrete on top that allows water to drain through a matrix of relatively large pebbles into a loose base of rubble beneath.
A statement by the company said it could not only help to tackle flash flooding in urban areas but may also help to reduce the heating of tarmac in hot weather.
They said: Permeable concrete allows surface water to freely drain through the wearing surface to the underlying ground with the ability to act as a reservoir during periods of high downfall.
‘During these periods this characteristic can aid in delaying the discharge of surface water into water courses or drainage systems reducing the risk of overwhelming systems and causing flash flooding.
‘During periods of rising temperatures and intense rainfall, water stored within the system evaporates creating a cooling effect reducing surface temperatures.’
The concept of permeable concrete has been around for nearly 60 years and it is often used under paving to help aid drainage, for example.
However, Tarmac claims advances in the way it can be compacted has now allowed it to be used as a top surface, capable of withstanding use by cars.
It claims the permeable concrete is ideal for large areas of concrete where water can be a problem, such as car parks or driveways.
The company also says the system could help prevent puddles on cycle paths and footpaths.
However, in areas that suffer extreme cold, the concrete is likely to be damaged as the water beneath freezes and causes the surface above to buckle and crack.
Tarmac said it had already installed the Topmix Permeable concrete in a car park in High Wycombe and on Worksop Golf Course.