ETH Study Could Remove Barriers to Low-Carbon Concrete

(CONNECT) A team at the Swiss Federal Institute of Technology Zurich (ETH) is working on an easy-to-conduct climate test for reinforced concrete. In the future, such a test could determine which type of low-carbon concrete is suitable for which location in the long term, without having to wait decades for data from actual structures. According to an international study involving ETH researchers, simply assessing the moisture content at a given location is not sufficient and puts more environmentally friendly types of concrete at a disadvantage.

However, the method already developed by the team clearly indicates that current European standards for assessing the impact of climate on the susceptibility of reinforced concrete to corrosion fall short. “The climate plays a much bigger role than we expected,” Ueli Angst, professor of materials durability at ETH, is quoted as saying in a press release. "The same concrete can behave completely differently in a different climate." Nevertheless, European standards currently classify the four study sites—Zurich, Bergen (Norway), Manaus (Brazil), and Huailai (China)—as belonging to the same category: “alternating wet and dry.”

However, in Bergen and Manaus, it is evident that steel rusts at different rates despite receiving the same annual rainfall. According to the ETH study, the key factor is how rainy and dry periods alternate. In addition, the team's model calculations showed that low-carbon concrete lasts 50 years or longer at certain locations than at others. Instead of using the same concrete everywhere according to the same rules, we need to take greater account of a structure’s location in the future.

“As a result, current standards can become an obstacle to new and more environmentally friendly materials,” said Angst. According to the report, the new approach could eliminate such an obstacle. This is because many of today's testing methods were developed for conventional cements and no longer account for the specific properties of climate-friendly concrete types. Now, Angst and his team also want to develop a simple and quick method for risk assessment with regard to climate change. ce/mm