Pour the bubbly

An Auckland researcher is working on an airy way to produce greener concrete.

- Veronika Medyha

In the wake of natural and climate disasters, we often talk about building back better, but then continue to use the same construction materials because they are usually the cheapest and most easily available.

Concrete is a good example. It has been poured into buildings and bridges for centuries because of its strength, durability and the relatively simple recipe for making it. Worldwide, we now use 30 billion tonnes of concrete a year, three times more than four decades ago. Demand for it is rising more steeply than for steel or wood, and it makes up by far the largest share of all human-made building materials, which now collectively outweigh Earth's entire living biomass.

In many ways, concrete is an ideal material for climate-resilient buildings, except for the carbon footprint of one of its main ingredients - cement.

At least 8% of global CO₂ emissions come from the cement industry alone. But efforts to decarbonise concrete are under way, and they may improve some of its properties.