In a world increasingly demanding sustainable infrastructure, the construction industry finds itself grappling with a dual challenge: maintaining the integrity of structures while minimising environmental impact. Enter fungi-based self-healing concrete—a revolutionary approach to repair cracks and extend the life of concrete using biological agents. As researchers explore the potential of this innovative material, it promises to reshape how we think about construction sustainability.
Image courtesy: LMS Technologies
Cracking the Problem with Concrete
Concrete, the backbone of modern infrastructure, has a durability problem. Bridges, dams, and highways are all susceptible to cracking over time due to environmental stressors, seismic activity, and material limitations. These cracks often compromise structural integrity, leading to frequent and costly repairs.
Globally, the construction industry is responsible for 8% of carbon dioxide emissions, primarily due to cement production. With over 4 billion tonnes of cement manufactured annually, the pressure to find eco-friendly solutions is mounting. While modern admixtures like fly ash and silica fume can enhance concrete’s durability, they don’t address repair needs. Fungi-based self-healing concrete presents an entirely new paradigm: a living material capable of autonomous repair.
What Is Self-Healing Bioconcrete?
Self-healing concrete integrates microorganisms such as bacteria or fungi within its matrix. When cracks develop, these microorganisms activate and repair the damaged areas by precipitating calcium carbonate (CaCO₃), a compound that mimics natural limestone.
Fungi, in particular, are emerging as a superior option in this field. Unlike bacteria, fungi tolerate more extreme conditions and require simpler nutrients to thrive. Fungal spores remain dormant during concrete curing, with its high pH and temperature, but germinate when cracks form and moisture collects. Once active, the fungi begin producing CaCO₃, effectively sealing cracks from within and preventing further structural damage.
Graphical abstract of research led by Pui Yan Wong, Joyabrata Mal, Anna Sandak, Lijun Luo, Jianxiong Jian and Nirakar Pradhan, published last October in Science of The Total Environment.
Fungi as a Key Player
Recent research highlights the resilience of certain fungal strains, such as Trichoderma reesei, in harsh concrete environments. These fungi demonstrate:
High pH tolerance: Vital for surviving the early alkaline conditions of concrete curing.
Thermal resilience: Spores can endure temperatures up to 55°C, a typical by-product of concrete hydration.
Longevity: Dormant spores remain viable for extended periods, activating only when conditions are favourable.
The fungi’s ability to form bio-minerals makes them an ideal candidate for large-scale applications in bioconcrete.
Representative images of fungal cultures with biomineralization or organomineralization capacity
Sustainability Benefits of Fungi-Based Concrete
Reduced Resource Demand: By extending the lifespan of concrete structures, self-healing bioconcrete minimises the need for new material production.
Lower Carbon Emissions: Fewer repairs and replacements mean reduced cement manufacturing, which directly cuts CO₂ emissions.
Energy Efficiency: Self-healing mechanisms eliminate the need for intensive manual inspections and repairs, reducing overall maintenance energy.
The construction sector’s sustainability goals align perfectly with these benefits. For example, the International Energy Agency estimates that the global building floor area will double by 2060, requiring sustainable solutions like fungi-based bioconcrete to mitigate the ecological burden.
Challenges and the Road Ahead
While promising, implementing fungi-based bioconcrete is not without obstacles:
Cost and Scalability: Encapsulation of microorganisms and maintaining their viability on a large scale remain expensive.
Optimisation of Delivery Systems: Techniques such as vascular networks or capsules for microbial agents need refinement to maximise effectiveness.
Acceptance in the Industry: Convincing stakeholders of the reliability and cost-effectiveness of this technology is crucial for widespread adoption.
Researchers are also exploring machine learning tools to model and optimise microbial activity, which could further enhance the performance of fungi-based self-healing concrete in diverse environments.
Challenges and future prospects in the development of self-healing bioconcrete technologies.
A Step Toward Resilient Infrastructure
The potential applications of fungi-based bioconcrete extend beyond repairing cracks. Coastal structures, prone to extreme conditions, could benefit significantly from its self-healing capabilities. In seismic zones, where crack formation is inevitable, this technology could reduce repair costs while ensuring safety.
As construction activity ramps up globally, solutions like fungi-based bioconcrete offer a compelling opportunity to build resilient and eco-friendly infrastructure. While more research is needed, the integration of living materials in construction signals a shift toward a more sustainable future—one where nature-inspired innovation meets the challenges of modern urbanisation.