In the quest for sustainable construction materials that don’t compromise on performance, a team of researchers led by Asmaa A. Selim from the Department of Civil Engineering at Benha University in Egypt has made a significant breakthrough. Their work, published in the journal *Next Materials* (which translates to “Next Materials” in English), explores the potential of hybrid fibre reinforcement in limestone calcined clay cement (LC3) mortar, offering a promising approach to optimize both strength and fire resistance.
LC3 is an innovative binder that replaces up to 60% of ordinary Portland cement (OPC) with a blend of calcined clay and limestone, reducing CO₂ emissions by up to 40%. While LC3 has shown mechanical and durability properties comparable to OPC, its fire resistance has been a critical concern, particularly in constructions exposed to high temperatures.
Selim and her team investigated the mechanical and fire-resistant performances of LC3-based mortars incorporating polypropylene (PP) fibre, basalt (BS) fibre, and their hybrid combinations (PP-BS). “The goal was to enhance the fire resistance of LC3 composites without compromising their mechanical properties,” Selim explained.
The results were promising. After an hour of exposure to the ASTM E119 cellulosic fire curve, the LC3-plain mortar without fibre experienced complete failure, retaining 0% of its original strength. However, the 0.3% PP-reinforced LC3 mortar exhibited the best residual results, retaining 66.46% and 18.78% of its original compressive and flexural strength, respectively.
The team also prepared hybrid LC3 composites by adding BS fibres at different levels to the 0.3% PP-reinforced LC3 optimum mortar. While the BS-reinforced LC3 mortar experienced explosive failures under rapid-fire exposure, the hybrid fibre-reinforced mortars demonstrated superior performance. “Hybrid fibre reinforcement offers a balanced solution, improving the overall mechanical properties and fire resistance compared to single-fibre and fibre-free systems,” Selim noted.
This research could have significant implications for the construction and energy sectors. As the world shifts towards greener building materials, the development of LC3 with enhanced fire resistance could open up new possibilities for sustainable infrastructure development. Moreover, the improved fire resistance could enhance the safety of buildings, particularly in fire-prone areas.
The study suggests that hybrid fibre reinforcement could be the key to unlocking the full potential of LC3. As Selim puts it, “This approach not only promotes sustainability but also ensures the safety and durability of structures.” With further research and development, this innovative material could become a staple in the construction industry, contributing to a more sustainable and resilient built environment.
The findings were published in the journal *Next Materials*, marking a significant step forward in the quest for sustainable and safe construction materials. As the world grapples with the challenges of climate change and urbanization, such innovations offer hope for a greener and safer future.