Influence and Contribution of High-Strength Steels in Connection with Their Use in Anchoring Systems and Their Manufacturing Processes on Co2 Reduction - Yesterday, Today, Tomorrow

In most cases, geotechnical anchoring systems consist of a steel load-bearing element that is anchored in the ground with cement mortar and, if necessary, additional corrosion protection measures. In this contribution, the influence of the steel load-bearing element on the CO2 footprint of geotechnical systems will be investigated and ways of positively influencing the CO2 footprint will be shown. The following aspects will be examined: Production process of the steel The steel production process plays a major role in terms of CO2 emissions. This refers to the production of steel from iron ore via the blast oxygen furnace route or from steel scrap via electric arc furnaces as well as the production of the electricity used for the production process. European and national standardization processes are currently undergoing radical change, meaning that the CO2 footprint figures resulting from the manufacturing process will have a significant impact on the use of the product in the future. The formal aspect should also be part of the consideration. Choice of anchoring system The choice of a suitable anchoring system leads to not inconsiderable differences in the carbon footprint. The user has the choice between systems that are easy to handle and offer advantages in terms of design, but at the same time require a high material input and therefore have a negative impact on the CO2 footprint. Here, the user already has a considerable influence on the choice of a suitable anchoring system today. Use of high-strength steels A third point on the road to CO2 reduction is the use of high-strength steels. The aim is to show how the use of high-strength geotechnical anchoring systems can contribute to CO2 reduction. The aspects to be considered when using high-strength steel are manifold. In addition to the advantages in terms of handling and occupational safety, the economic benefits such as lower freight costs, the possibility of carrying out different work steps in parallel and, last but not least, the up to 85% reduction in CO2 compared to iron ore-based products should also be emphasized. High-strength steels have been established for ground anchors in the form of strands since the 1950s, but have hardly played a role in other anchoring systems such as micropiles and soil nails. Metallurgical aspects will be examined. Examples from other areas of the construction industry will also illustrate the applicability and thus show ways for the use of high-strength steels as a forward-looking concept in the geotechnics of tomorrow and as part of the concept for CO2 reduction. (Example 1: The development of high-strength SN anchors was able to prove its practical suitability in the tried and tested tunnel anchor technology for driving various tunnels such as the Trimberg, Boyneburg and Stuttgart airport tunnels. A new steel grade enables the use of an SN anchor, which reduces the cross-section and weight by 44% compared to conventional products. Example 2: The use of high-strength reinforcing steels, such as those used in many high-rise buildings in New York or Frankfurt, can also be transferred to geotechnical applications - always taking into account the correct technical use).