In an era where sustainability and safety are paramount, a groundbreaking study from the National University of Sciences and Technology (NUST) in Pakistan is set to revolutionize the construction industry, particularly in the energy sector. Led by Muhammad Saqib Khan, the research delves into the performance of fiber-reinforced recycled aggregate concrete (RAC) under elevated temperatures, offering a promising solution to both environmental and fire safety challenges.
The study, published in Scientific Reports, explores the potential of recycled aggregate concrete reinforced with fibers to enhance high-temperature performance. This innovation is crucial for the energy sector, where fire hazards are a significant concern, and the demand for sustainable building materials is ever-increasing.
Khan and his team began by evaluating concrete mixtures with varying percentages of recycled aggregate—0%, 25%, and 50%—at room temperature, 300°C, and 600°C. The results were striking. Conventional concrete (RAC00) showed a 16% reduction in compressive strength at 300°C and over 50% at 600°C. In contrast, the mixture with 25% recycled aggregate (RAC25) demonstrated remarkable resilience, with only a 1% strength decline at 300°C and a 28% reduction at 600°C. “This makes RAC25 the most effective composition for further study,” Khan noted, highlighting its potential for real-world applications.
The second phase of the study involved incorporating steel fibers (SF) and polypropylene fibers (PPF) into RAC25. The results were even more impressive. RAC25 with steel fibers showed substantial tensile strength improvements: a 5.6% increase at room temperature, 24.8% at 300°C, and 28.3% at 600°C. “Steel fibers enhanced strength across all temperatures,” Khan explained, underscoring their effectiveness in maintaining structural integrity under heat.
Polypropylene fibers, however, showed a different pattern. While they increased tensile strength by 12.5% at room temperature, their performance declined at higher temperatures, with a 9.9% decrease at 300°C and 32.9% at 600°C. This indicates that while polypropylene fibers can improve ductility and toughness at lower temperatures, they are not suitable for high-temperature applications.
The study also employed statistical modeling using ANOVA and response surface methodology (RSM) to confirm the validity of the findings. The high model validity (R2 > 0.80) further strengthens the case for RAC25 with steel fibers as a sustainable, heat-resistant construction material.
The implications of this research are far-reaching. For the energy sector, where fire safety is a critical concern, this innovation offers a sustainable solution that can withstand high temperatures without compromising structural integrity. Moreover, by promoting the use of recycled aggregates, it addresses the environmental burden of construction and demolition waste, aligning with global sustainability goals.
As the construction industry continues to evolve, the integration of recycled materials and advanced fiber technologies is set to play a pivotal role. This study from NUST not only paves the way for more sustainable and fire-resistant building materials but also sets a benchmark for future research in the field. The energy sector, in particular, stands to benefit significantly from these advancements, ensuring safer and more sustainable infrastructure for the future.