The building sector is responsible for about 50% of all materials taken from the earth and for the production of about one-third of all waste produced in Europe. The transition of the building sector to a circular economy is thus of primordial importance to mitigate both problems.
Characterizing material flows and environmental impacts of the construction value chain is crucial to boost the circularity approach since the building design phase. Material flow analysis (MFA) and life cycle assessment (LCA) are two of the most known and diffuse methodologies to quantify the environmental and economic impacts of the built environment through a circular approach. While there have been advancements over the last decade in the implementation of various circular strategies, the building industry urgently needs to implement more effective recycling and reuse procedures to lower the rate of consumption by applying a circular economy framework, overcoming barriers and limits, such as data quality and availability used in the assessment process.
On the other hand, steel is the most recycled material in the world and can be recycled indefinitely. Recycled steel makes up about 40 percent of the total amount of steel produced, avoiding almost 950 million tons of CO2 emissions and 1 billion tons of iron ore[1]. However, appropriate metrics are necessary to quantify all benefits and also burdens of recycling and reusing steel in the context of building design.
Hence, in this paper, a hybrid methodology is proposed that explores the synergies between LCA and MFA in the assessment of the circularity of buildings. Furthermore, the proposed approach aims to identify and quantify all potential benefits of the circularity of buildings over the complete life cycle. In addition, the proposed approach is applied to a steel building, showing the advantages of steel structures in relation to the circular economy.
[1] https://www.theworldcounts.com/challenges/planet-earth/mining/advantages-of-recycling-steel