Mixing concrete is like baking a cake, says Antonio Catarino, one of Bton’s managing directors. “If you only mix the liquid ingredients of a dough, it’s easier than with flour. If you use flour, you need more strength.” So at Bton they first mix the cement with water and only add sand and gravel later. That uses less energy, says Catarino. Bton only uses renewable energy and locally available resources for its production. The company has written many recipes and developed more than 6,000 mixing techniques. They can even incorporate desert sand, which is available in huge quantities.
Bton’s building material is also up to 40 percent lighter than conventional concrete because so-called lightweight aggregates, i.e. porous aggregates, can be incorporated. This means that the concrete does not have to bear as much of its own weight. The company uses its new material to build prefabricated parts for buildings. It can produce around 2,000 housing units a year. This alone is only a small part of Bton’s production. But in addition to the Soltau plant, in which the company has invested nine million euros, it wants to build further plants. Inquiries and orders come from the USA, Brazil, Singapore, Dubai and Saudi Arabia.
Are the goals that the cement industry has set itself realistic? In Germany, completely CO₂-neutral production of concrete would certainly be feasible in ten to 15 years,” says Catarino, but globally we are talking about more than half a century.”
There are several approaches to making the concrete industry more climate-friendly. But there isn’t one brilliant idea yet. Ultimately, a combination of ideas is needed to reduce the huge CO₂ emissions. Because without concrete, nothing works in the construction industry, not even in the world of tomorrow. Dams are made of concrete, as are retention basins for flood protection, and so are wind turbines.