Keep friends close, but enemies closer. That is the mantra behind a new technology now gaining ground. Cement production — 4 billion tonnes worldwide — annually accounts for 7 per cent of global CO2 emissions. The way to square it up is by making use of CO2 alongside cement — in concrete production.
When you inject liquid CO2 into wet concrete, it turns into ‘carbon dioxide snow’, which reacts with calcium ions in the cement to form hard calcium carbonate nano particles. The dreaded greenhouse gas is therefore permanently imprisoned in concrete — 17 kg of it per cubic metre of concrete.
The aim is the same as pouring water over freshly laid concrete for hardening it; only, the results are better.
The claim that carbonaceous concrete costs as much as conventional concrete may not be true. But what’s important is that CO2-concrete has begun to attract climate funds. Last September, Amazon and Microsoft were part of a consortium that invested in Canadian company CarbonCure, a player in this technology, which aims at bringing down emissions by 500 million tonnes by 2030. All ‘set’ for the future, so to speak.
