In the quest for sustainable construction materials, a groundbreaking study led by Osama Zaid at the Institute of Material Technology, Building Physics, and Building Ecology, Faculty of Civil and Environmental Engineering, TU Wien, has shed new light on the potential of mine tailings in ultra-high-performance fiber-reinforced concrete (UHPFRC). The research, published in ‘Scientific Reports’ (Nature), explores how mine tailings powder (MTP) and mine tailings sand (MTS) can be used to replace cement and quartz sand, respectively, in UHPFRC, offering a promising solution to the environmental challenges posed by conventional concrete production.
The study delves into the mechanical and durability properties of UHPFRC with varying MTP and MTS contents, revealing significant enhancements in key performance indicators. “The optimal mix of 15% MTP and 60% MTS not only enhances compressive strength by 12.49% but also reduces autogenous shrinkage by 49.28% and significantly improves sulfate resistance,” Zaid explains. These findings are particularly relevant for the energy sector, where infrastructure often faces harsh environmental conditions and requires materials with exceptional durability and strength.
The research highlights that the optimal mix achieves a compressive strength of 165.2 MPa at 90 days, a remarkable improvement over traditional UHPFRC. Additionally, the mix demonstrates a residual compressive strength of 115.2 MPa and a mass loss of 25.4% in sulfate resistance tests, indicating its potential for use in aggressive environments. The workability tests show a decrease in flow spread, which is a trade-off for the enhanced mechanical properties, but the overall performance gains are substantial.
The study also reveals that the incorporation of mine tailings leads to a slower and more controlled hydration process, as evidenced by a delayed Tmax in the heat of hydration analysis. This controlled hydration contributes to the material’s long-term durability and mechanical performance. The microstructural analysis further supports these findings, showing a reduction in porosity and enhanced hydration stability with increasing mine tailings content.
The implications of this research are far-reaching for the construction industry, particularly in the energy sector, where the demand for durable and sustainable materials is high. The use of mine tailings in UHPFRC not only reduces the environmental impact of concrete production but also provides a viable solution for managing mine waste. As Zaid notes, “The improved microstructural characteristics contribute to the material’s long-term durability and mechanical performance, making it a viable option for sustainable construction practices.”
This research paves the way for future developments in the field, encouraging further exploration of alternative resources in construction materials. As the energy sector continues to evolve, the need for sustainable and high-performance materials will only grow, and this study offers a compelling path forward.