N-Ö-B - Sustainability benchmarks for Austrian concretes, a building block on the way to CO2 neutrality

On the way to climate neutrality in the construction industry (CO neutrality by 2040 in Austria and 2050 in the EU), the greening of concrete construction represents a major challenge. Concrete is the most widely used building material worldwide and, with its emission-intensive component Portland cement clinker, contributes significantly to CO emissions (globally around 8%). On the other hand, it is indispensable for the construction of sustainable infrastructure, the expansion of renewable energies, buildings for climate change adaptation and much more, even in times of transformation to a sustainable environmentally friendly economy. In order to be able to use concrete in a climate-friendly way, a step-by-step complete decarbonization of concrete construction is necessary, which can succeed through contributions from all actors along the concrete production value chain. This project makes a significant contribution in the field of concrete production and the design of concrete structures by laying the foundations for climate-compatible, performance-oriented concrete concepts. In addition to climate compatibility and functional performance, the aspect of the greatest possible durability of concrete plays a decisive role in its sustainability. Good durability properties of concrete against the multiple impacts (exposures) and high quality during execution enable a long service life and thus reduced environmental impacts and costs over the entire life cycle. The latter is particularly important for the long-term economic viability of public buildings, for example. The existing descriptive regulations of concrete standardization (such as ÖNORM B 4710-1:2018) make it difficult to really exploit the existing potential of decarbonization of concrete. Obstacles include (i) rigid specifications for minimum cement content, (ii) limits on the allowable amount of low-emission additives in the binder, and (iii)the lack of class-forming requirements for durability characteristics of concrete types, and (iv) the lack of reduction pathways for CO emissions. The industry-wide basis for new performance-based design and verification concepts for climate-compatible and durable concrete (based on statistically validated, extensive data and testing experience) must therefore first be created.