The bridge may not look that special. For 150 years, various bridges have transported sheep, cows, cars and skiers over the river Grødøla in Sunndal. When the stone bridge had to be replaced, the local road department contacted world-class researchers. With the result. – This is world news! We think this is the solution of the future, says Grethe Hjetland in Norsk Hydro. Now the small bridge, surrounded by beautiful nature, will become an advertisement for one of the planet’s largest and most polluting industries: the concrete industry. ALUMINUM: Grethe Hjetland from Hydro admires the aluminum under the new bridge in Sunndal. Photo: Roar Strøm / news Basic concrete There is an enormous amount of concrete on Earth. There will soon be more concrete than biomass on our planet. Around 8 percent of CO₂ emissions in the world come from concrete. The bridge in Sunndal is the first in the world to be built with aluminum and concrete. – Everyone around us said that “aluminum and concrete don’t go together”, says Harald Justnes, the inventor behind it all. THE MASTER BRAIN: Harald Justnes, chief researcher at Sintef. Photo: Sintef Cement is used in concrete, which is reinforced with a reinforcement of steel bars on the inside. Both the cement and the steel cause large climate emissions. In addition to the steel rusting. After 50–100 years, you have to spend a lot of money on repairs. In 2015, Sintef researcher Justnes was asked a question at work: – Can you not reinforce with (stainless) aluminium? No, because the aluminum would weather due to the high pH in concrete. Nevertheless, on the way home the chemist got an idea. 80 percent less CO₂ – What if you change the concrete itself? And did it make it less basic? thought Justnes Soon he will start experiments, and even replace more than half of the cement with burnt clay. Something that turned out to work, and which today he gives telephone calls from all over the world. REVOLUTION: Environmental concrete above, aluminum below. Photo: Roar Strøm / news There are many advantages to replacing steel with aluminum and cement with clay: Clay produces lower emissions, as it is burned in approx. 800 degrees, compared to 1450 degrees for cement. The same applies to the metal. Aluminum needs less than half the heat that steel needs. That means less current and emissions. The metal can be obtained, among other things, from old car engines. Altogether, CO₂ emissions are reduced by between 60 and 80 per cent. In addition, one can manage with much thinner concrete slabs, and will save large sums by avoiding maintenance and demolition. PROUD: Grethe Hjetland and Trond Furu from Hydro and Gunnar Olav Furu from the local road team at the new climate bridge in Sunndal. Photo: Roar Strøm / news Anti-rust box On the bridge in Sunndal they are proud. Grethe Hjetland from Hydro wants to sell “concrete of the future” to the whole world. – This “green” concrete can replace all other concrete. Perhaps with the exception that it should be used with care where there is a risk of fire. They hope that the bridge will become an attraction, in addition to transporting people and cattle weighing up to 10 tonnes. A small box with sensors under the bridge will ensure that the aluminum is not weakened. UP TO 10 TONNES: The first car over the bridge went well in any case. The car was a Mitsubishi Outlander. Photo: Roar Strøm / news “Forever” What is the challenge before this becomes the new standard? – Getting hold of enough clay, says researcher Harald Justnes. Today, little clay is burned around the world. But how long will the new climate bridge actually last? For almost “eternal time”, according to the man behind the idea. – There are Roman constructions that stand today, but they had neither reinforcement nor frost. With aluminium, we will beat the Romans, says Justnes. He vouches for an “extreme” lifespan of at least a thousand years. – I see no reason why I should not be able to guarantee it. I won’t live long, so no one can sue me, Justnes chuckles.
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New bridge in Sunndal with concrete of the future reduces CO₂ emissions by 80 percent – news Møre og Romsdal – Local news, TV and radio
