In the quest for sustainable construction, a groundbreaking study published in the journal *Discover Civil Engineering* (translated from the original Persian title) has shed light on the often-overlooked environmental impact of coarse aggregates in concrete. Led by Muhammad Bilal Subhani from the Department of Civil Engineering at Mirpur University of Science and Technology (MUST), the research explores the potential of steel slag aggregates—a by-product of steel production—as a sustainable alternative to natural coarse aggregates in mid-rise buildings.
The study focuses on a 10-story mid-rise building, designed and analyzed using ETABS software, incorporating laboratory-tested physical and mechanical parameters of modified concrete. The research team conducted a comprehensive 100-year Life Cycle Assessment (LCA) to evaluate the environmental impact of the designed structure compared to a conventional concrete building.
The results are striking. By replacing natural coarse aggregates with 100% steel slag aggregates, the study demonstrates a complete reduction in natural aggregate consumption, saving a staggering 11,100 tons of crushed stone aggregates. This substitution leads to a significant reduction in CO₂ emissions—69 tons—and a notable decrease in ozone emissions, amounting to 500 kg over the building’s lifespan. Additionally, this approach conserves approximately 2 million gallons of water, which would otherwise be required for natural aggregate production.
“Current design codes primarily focus on the sustainability of concrete as a whole, with limited guidance on the environmental benefits of replacing individual components like coarse aggregates,” explains Subhani. “This research highlights the need for revised guidelines that integrate material-specific sustainability metrics to encourage the systematic use of alternative aggregates.”
The environmental impact of coarse aggregates was measured following guidelines and data from renowned stone aggregate associations, as referenced in the study. Despite the clear advantages, the lack of explicit provisions in design codes for quantifying the environmental benefits of alternative aggregates limits their widespread adoption.
This research has significant implications for the construction industry and the energy sector. As the demand for sustainable construction practices grows, the adoption of alternative aggregates like steel slag could play a pivotal role in reducing the environmental footprint of buildings. The study underscores the importance of integrating material-specific sustainability metrics into standards to support environmentally responsible construction practices.
Subhani’s work, published in *Discover Civil Engineering*, not only provides a roadmap for future research but also calls for a paradigm shift in how we approach material sustainability in construction. By addressing the gap in knowledge related to coarse aggregate replacement, this study paves the way for more informed decisions and innovative solutions in the quest for greener buildings.
As the construction industry continues to evolve, the insights from this research could shape future developments, encouraging the adoption of alternative aggregates and promoting a more sustainable built environment. The journey towards sustainable construction is complex, but studies like this one bring us one step closer to achieving our goals.