In the quest for sustainable infrastructure, scientists are turning to an unlikely ally: bacteria. A recent study published in *Case Studies in Construction Materials* (translated as “Studies in Construction Materials”) has shed light on the thermal dependency of microbial self-healing in concrete, offering promising insights for the energy sector and beyond. Led by Seleem S.E. Ahmad from the Engineering Materials Department at Zagazig University in Egypt, the research explores how different strains of bacteria perform at various temperatures, from room temperature down to sub-zero conditions.
The study focuses on two bacterial strains, Bacillus Megaterium (BM) and Bacillus Sphaericus (BS), and their ability to heal cracks in concrete through a process known as Microbially Induced Calcite Precipitation (MICP). This natural process involves bacteria precipitating calcium carbonate, effectively sealing cracks and restoring the material’s integrity. “The potential for bacterial self-healing concrete to extend the lifespan of infrastructure is immense,” says Ahmad. “Our research aims to understand how different strains and concentrations of bacteria perform under varying thermal conditions, which is crucial for real-world applications.”
The team tested the concrete samples at 24°C and sub-zero temperatures (-16±2°C and -24°C), using a range of analytical techniques including energy-dispersive spectroscopy, scanning electron microscopy, and X-ray diffraction. They also employed ultrasonic, compressive, and flexural testing to assess the material’s mechanical properties.
The results were striking. At room temperature, the concrete’s compressive strength increased by 40.24% after 28 days when treated with Bacillus Megaterium. Moreover, at 0°C with a 2.5% bacterial concentration, both strains achieved 100% crack healing. However, the performance of the two strains diverged at lower temperatures. Bacillus Megaterium demonstrated remarkable cold tolerance, increasing compressive strength by 54.87% at 0°C, while Bacillus Sphaericus showed a drop in performance.
“This research highlights the importance of selecting the right bacterial strain for specific environmental conditions,” explains Ahmad. “Bacillus Megaterium’s superior performance at low temperatures makes it a promising candidate for applications in cold climates or seasonal environments.”
The implications for the energy sector are significant. Infrastructure in cold regions, such as oil and gas pipelines, offshore wind turbines, and Arctic construction projects, often faces harsh environmental conditions that accelerate material degradation. Bacterial self-healing concrete could offer a sustainable and cost-effective solution, reducing maintenance costs and extending the lifespan of these critical assets.
Furthermore, the study’s findings could pave the way for future developments in bio-based construction materials. As the demand for sustainable infrastructure grows, researchers are increasingly turning to nature-inspired solutions. “This research is just the beginning,” says Ahmad. “We are exploring the potential of other bacterial strains and optimizing the conditions for MICP to further enhance the performance of self-healing concrete.”
The study, published in *Case Studies in Construction Materials*, provides a valuable contribution to the field of bio-based construction materials. As the world seeks to build more sustainable and resilient infrastructure, the insights gained from this research could shape the future of construction, offering a greener and more durable alternative to traditional materials.