Sometimes holes make things better—think Swiss cheese and doughnuts. But can holes also combat climate change?
In a world where extreme flooding and other climate-change-related weather events are becoming more common—and inflicting serious damage on the planet—holes in concrete, an often-used construction material, may actually improve the environmental sustainability of cities globally.
Much of concrete’s appeal as a building material comes from its simplicity. Concrete is simply a mixture of water, sand, gravel and powdered cement. Concrete is also cheap, easy to use and can be sculpted into nearly any shape.
However, concrete is also relatively water-resistant; a parking lot or a road paved with concrete doesn’t absorb it. In times of extreme precipitation, concrete can exacerbate the problem. But good news: new technology is changing this.
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By removing the sand from the mixture but keeping the large aggregates, experts have discovered that it’s possible to make a new type of concrete that is porous, allowing water to filter through the pavement and into the soil below.
The EPA has recently begun experimenting with porous concrete in a car park at its Edison Environmental Centre in Edison, New Jersey. The 110-vehicle car park was completed in 2016 and features 300,000-square-feet of permeable pavement.
Michael Borst, a chemical engineer in the EPA’s National Risk Management Research Laboratory, and who specialises in green infrastructure research and finding ways to help local councils develop cost-effective strategies to meet environmental goals, oversaw the project.
Borst said he and the agency were initially sceptical of the purported benefits of porous concrete. But after the Edison Centre car park experiment and other testing, Borst said: “This stuff works”.