In the quest to reduce carbon emissions in the construction industry, sustainable cementitious materials have emerged as a promising alternative to traditional concrete. However, their performance under high temperatures has been a subject of scrutiny. A recent review published in the journal *npj Materials Sustainability* (translated as “Nature Partner Journal Materials Sustainability”) sheds light on this critical aspect, offering insights that could shape the future of sustainable construction.
Led by Zhengyu Zhang from the School of Civil and Environment Engineering at Nanyang Technological University, the review examines the high-temperature behavior of various sustainable concrete materials. These include supplementary cementitious materials (SCMs) blended with ordinary Portland cement (OPC), ultra-high-performance concrete (UHPC), recycled aggregate concrete (RAC), alkali-activated concrete (AAC), limestone calcined clay cement (LC3), and CO2-cured concrete.
The study reveals that the performance of these materials at elevated temperatures varies significantly. For instance, SCM-blended systems show differing results based on the type of material used. “Fly ash generally enhances thermal stability, while slag improves strength retention, and silica fume can potentially increase spalling susceptibility,” Zhang explains. This variability underscores the importance of material selection and blend optimization in achieving desired thermal performance.
UHPC, known for its superior mechanical properties, also presents a higher risk of spalling at high temperatures. However, this risk can be mitigated through the addition of fibers, offering a potential solution for enhancing its fire resistance.
Recycled aggregate concrete (RAC) shows promising results, with some studies reporting comparable or even enhanced high-temperature behavior relative to traditional concrete. This finding highlights the potential of RAC in reducing the environmental impact of construction materials without compromising performance.
Alkali-activated concrete (AAC) generally exhibits good fire resistance, influenced by the type of precursor materials and activator used. Meanwhile, LC3 concrete demonstrates similar strength retention to OPC at moderate temperatures, suggesting its viability as a sustainable alternative.
CO2-cured concrete performs well up to 600°C but experiences rapid degradation at higher temperatures due to the decomposition of calcium carbonate. This limitation points to the need for further research to enhance its thermal stability.
The review elucidates the mechanisms influencing the performance of sustainable concrete materials at elevated temperatures and identifies critical research directions to enhance their fire resistance. As Zhang notes, “This review provides a comprehensive understanding of the high-temperature behavior of sustainable concrete materials, paving the way for their broader adoption in construction applications.”
The findings of this research have significant implications for the energy sector, particularly in the development of sustainable and energy-efficient construction materials. By understanding the thermal behavior of these materials, engineers and architects can design buildings that are not only environmentally friendly but also safe and resilient under extreme conditions.
As the construction industry continues to seek sustainable alternatives to traditional materials, this review offers valuable insights that could shape the future of sustainable construction. By addressing the challenges and opportunities highlighted in this research, the industry can move closer to achieving its sustainability goals.