Factors Influencing CO2 Sequestration via Olivine Weathering in Cement-Based Building Materials

Enhanced silicate rock weathering has been proposed as a geoengineering strategy to sequester atmospheric CO2. Incorporating this approach into cement-based building materials could help offset production-related emissions. Although olivine is widely studied for enhanced weathering, its effectiveness in cementitious systems remains unexplored. We present results from field and laboratory experiments on an olivine-containing façade plaster prototype developed with Knauf Gips KG. After an 18-month field test, no significant in situ olivine weathering was observed in the exposed plaster samples. Laboratory experiments show that olivine dissolution is suppressed at alkaline pH. This suppression is consistent with carbonate ion inhibition of surface Mg sites as described in the literature but was not independently verified here. Whether this limitation extends to other cementitious systems with different pore structures, moisture regimes, or binder compositions requires further investigation. Based on published dissolution behavior, Ca/Mg-aluminosilicates may represent more suitable alternatives, though this was not experimentally tested.