In the quest for sustainable construction materials, researchers have turned to seawater and sea sand as viable alternatives to traditional concrete components. However, the behavior of these materials under extreme conditions, such as high temperatures, has remained a critical gap in the knowledge base. A recent study published in the journal *Developments in the Built Environment* (translated from Chinese as *Advances in Building Science*) sheds light on this very issue, offering promising insights for the energy sector and marine engineering.
Led by Yafeng Xu from the School of Civil Engineering at Shandong Jiaotong University in China, the research team investigated the mechanical behavior and microstructural degradation of seawater sea sand concrete (SWSSC) after exposure to high temperatures, ranging from 23°C to 800°C. The study also explored the reinforcing effects of basalt fibers on SWSSC, a topic that has seen limited exploration until now.
The findings reveal a complex interplay between temperature and material properties. As temperatures rose, the compressive strength of SWSSC initially decreased, then slightly recovered, and finally dropped sharply. This behavior was attributed to the dehydration of calcium silicate hydrate (C-S-H) and the decomposition of ettringite (AFt), Friedel’s salt, and calcium hydroxide (Ca(OH)2). The splitting tensile strength, on the other hand, showed a continuous decline with increasing temperature.
The incorporation of basalt fibers into SWSSC (SWSSC-B) was found to mitigate these degradation effects significantly. At a fiber content of 0.2%, the compressive and tensile strengths increased by 65.5% and 14% at 600°C, respectively, compared to unreinforced SWSSC. “The fiber-bridging network plays a crucial role in delaying crack propagation and maintaining the structural integrity of the material,” explained Xu. This enhancement in mechanical properties at elevated temperatures could have substantial implications for the energy sector, particularly in applications where concrete structures are exposed to high temperatures, such as in offshore wind farms, nuclear power plants, and other energy infrastructure.
The study employed a combination of compressive and splitting tensile tests, along with scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses, to provide a comprehensive understanding of the mechanical and microstructural evolution of SWSSC and SWSSC-B under high-temperature exposure. The results not only offer experimental evidence but also theoretical insights that could guide the development of more fire-resistant SWSSC structures.
As the world continues to seek sustainable and durable construction materials, this research highlights the potential of basalt fiber-reinforced SWSSC as a viable option for marine and high-temperature applications. The findings could pave the way for innovative solutions in the energy sector, contributing to the development of resilient and environmentally friendly infrastructure. “This study provides a foundation for further research and practical applications, ensuring that our pursuit of sustainability does not compromise structural integrity,” Xu added.
In an industry where every innovation counts, this research marks a significant step forward, offering a glimpse into the future of sustainable construction and energy infrastructure.