Capturing CO2 by olivine weathering in facade plaster

The building and construction sector accounts for a significant proportion of current anthropogenic CO₂ emissions. Reducing the carbon footprint of building materials is difficult because some process-related CO₂ emissions cannot be avoided. While the industry is developing methods to reduce its emissions by capturing CO₂ from flue gas streams, this study investigates an alternative mechanism to reduce the carbon footprint of building materials, namely the incorporation of olivine into building materials such as façade plaster. Olivine is susceptible to weathering and reacts with CO₂ to form magnesium carbonate and silica.

In collaboration with the company Knauf Gips KG, an outdoor test facility will be built to monitor the mineralogical changes in olivine façade plaster under natural weathering conditions over a period of 18 months. In parallel, laboratory experiments will be carried out to accelerate the weathering process by continuous artificial weathering of the plaster samples. Fluids will be regularly sampled and analysed to detect potential environmental hazards, such as the release of nickel and chromium into the environment. All plaster samples will be analysed by X-ray diffraction (XRD) and scanning electron microscopy (SEM) to identify mineralogical and structural changes during the experiments. The extent of CO₂ mineralisation will be assessed based on mass balance calculations with the experimental reactants and their products. A sustainability assessment of the whole value chain will be carried out to determine whether olivine in building materials can effectively contribute to offsetting the CO₂ emissions of the construction industry.