Building codes are holding back low-carbon concrete. A new study shows why.
Building standards treat all concrete the same, hindering the use of greener concrete, but climate conditions play a much bigger role in determining a structure’s durability
Low-carbon concrete, which absorbs more carbon dioxide from the air and reduces its internal alkalinity, poses a potential problem for durability. This vulnerability to rust corrodes the steel reinforcement within the concrete. Building codes, designed to prevent such corrosion, inadvertently discourage the use of greener concrete even though it benefits the climate.
ETH Zurich's new study, published in Nature Communications, reveals why this dilemma exists. The researchers modeled corrosion in real-world conditions across four cities with distinct climates—Zurich, Bergen, Manaus, and Huailai. They discovered that climate, rather than the concrete's chemistry, is the main factor affecting corrosion.
Wet concrete can corrode up to 100 times faster than dry concrete, while the impact of different concrete mixes is comparatively minor. Consequently, low-carbon concrete might degrade quickly in a humid, rainy city like Manaus but hold up well in a dry city like Huailai. This finding suggests that building standards should be tailored to a structure's specific location rather than applying uniform rules across the board.
Lead researcher Ueli Angst emphasized the need for engineers to better understand how low-carbon concrete behaves under various weather conditions. By calibrating codes to a structure's actual location, low-carbon concrete could be widely deployed in climates where it performs well, without waiting for a breakthrough in materials science.
Written by urgent.news from Anthropocene Magazine's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
