09 Dec Ecologically and economically sound: the reuse of scrap steel
The construction industry has great potential to reduce resource consumption, CO2 emissions and waste generation in a climate-friendly way
Ecologically and economically sound: the reuse of scrap steel
Circular construction: The construction industry holds great potential for reducing resource consumption, CO2 emissions, and waste generation in a climate-friendly way. For example, load-bearing steel components from existing buildings could be reused after deconstruction. This is not only ecologically but also economically attractive. Terms like “repair” and “recycling” are widely known in relation to sustainability. More recent terms include “retrofitting” and “reuse.” Both significantly expand the sustainability portfolio and represent further pathways within a circular economy.
Recycling, Reuse, Retrofitting
Source of the image: European Commission: Joint Research Centre, Circular technologies in construction – Putting science into standards, Publications Office of the European Union, 2024, https://data.europa.eu/doi/10.2760/876431
Retrofitting involves extending the lifespan or adapting an existing building structure to changed usage scenarios or loads. The existing structure is assessed and then reinforced in a targeted manner or simply upgraded for the altered use.
In re-use, individual components or even entire components are dismantled and, after qualification of the geometrically unchanged components, reused in new buildings.
Source of the image: Worldsteel Association – Sustainability Indicator 2023 Report
Re-use is currently rather the exception.
While retrofitting is already well-established in the repair and reinforcement of structures such as bridges, the situation is different when it comes to reuse. The reuse of load-bearing components is currently infrequent, even though there are historical examples. Depending on the source, only about 5–14% of steel components are reused; the remaining 83–97% of dismantled steel is recycled. Reuse would save considerable energy and emissions compared to recycling: Recycling requires the steel to be melted down at temperatures of approximately 1,500–1,600°C.
The low reuse rate is partly due to the lack of standardized technical guidelines for reusing used components. To unlock the enormous potential of these materials, the components must be thoroughly inspected and requalified to ensure their suitability for reuse.
Our contribution to a standardized testing system for reuse
But things are changing! The Ministry of Regional Development and Housing of Baden-Württemberg recently published a new guideline on reuse in steel construction, laying the first scientific foundations for practical application. [1]
At the same time, we at IWT-Solutions AG are contributing to the development of a standardized testing system for the reuse of scrap steel. Together with the Institute for Steel Construction at RWTH Aachen University and the Technical University of Central Hesse, we have examined in more detail the non-destructive testing methods (here we could insert an internal link to StIM) that we have been using for years in the repair of structures, also for their suitability for reuse.[2]
Our question: How can we systematically characterize steels from existing structures using mobile and non-destructive StIM testing, evaluate the material properties and reliably qualify them for reuse?
StIM: minimal effort, maximum reliability
We have demonstrated that our StIM method enables requalification with minimal effort, little intervention in the load-bearing structure and the component itself, and, most importantly, with high reliability. This method is based on mobile optical emission spectroscopy (OES). It is particularly well-suited for mobile applications, such as in existing buildings or on construction sites. We are confident that the non-destructive testing of components, not only with mobile OES, and our findings will be incorporated into the testing procedures for the reuse of scrap steel.
If you would like to have the material properties of reusable steel components analyzed and evaluated today, please feel free to contact us.