By Ananta 
In an era where durable infrastructure is crucial for sustainable development, self-healing concrete has emerged as a game-changer. This groundbreaking technology possesses the ability to repair cracks and damage autonomously, ensuring the longevity of structures while reducing maintenance costs. This article delves into the world of self-healing concrete, exploring its working principles, real-world applications, and environmental advantages.
What is Self-healing Concrete?
Self-healing concrete is a special type of concrete that exhibits self-repairing properties. Self-healing concrete can repair its cracks by autonomous or autogenous methods. The use of self-healing concrete extends the wife span of the construction and will lead to more durability in concrete.
Self-healing concrete is a particular type of concrete. This concrete can retain its original state when it is subjected to cracks.
Self-healing is specially used to enhance the durability of concrete structures. The use of this concrete thus extends the lifespan of the construction.
What is Bio-concrete Concrete?
Bio-concrete is a material that produces minerals like calcium carbonate with the help of dormant bacteria present in the concrete. In this method, the bacteria will heal the cracks that appear on the surface of the concrete.
Bio-concrete is also known as Bacterial Concrete.
Why should we need Self-healing Concrete?
Concrete is the most efficient and widely used construction material because of its relatively low constant freedom of design. It can resist high compressive stress. But it cracks due to the weakness in tension, shrinkage, and fatigue loading which can reduce concrete’s toughness and increase permeability. This way the cracks can cause the reduction of concrete’s structural integrity, durability, and life span.
Through these cracks, aggressive substances enter the concrete. These aggressive substances cause concrete degradation and reinforcement corrosion. The repair of these cracks is very laborious and thus expensive.
In such a context, this concrete provides an actual solution. Self-healing in concrete is a process in which it retains its performance after the initial damage. The technology of Self-healing in concrete can reduce unnecessary maintenance costs and provide a longer material lifetime.
How Does Self-Healing Concrete Work?
At the core of self-healing concrete lies microorganisms or encapsulated healing agents embedded within the material. When cracks form, these agents are activated in response to moisture ingress, triggering a chemical reaction that fills the cracks and restores the integrity of the concrete. This self-repair mechanism not only prevents further deterioration but also enhances the structural performance of the concrete.
What are the Benefits of Self-Healing Concrete?
- Enhanced Durability: Self-healing concrete extends the service life of structures by effectively repairing cracks and preventing the ingress of harmful substances.
- Cost Savings: By reducing the need for frequent maintenance and repair, self-healing concrete offers significant cost savings over the lifespan of a structure.
- Environmental Sustainability: The longevity of self-healing concrete contributes to reduced resource consumption and carbon emissions associated with construction activities.
- Improved Safety: Self-healing concrete enhances structural integrity, thereby minimizing the risk of collapse and ensuring the safety of occupants and the public.
How is Self-Healing Concrete Utilized in Construction?
Self-healing concrete can be incorporated into various infrastructure projects, including bridges, highways, tunnels, and buildings. Research and development in this field have led to the commercialization of self-healing concrete products, offering a viable solution for sustainable construction practices.
Best Ways to Implement Self-Healing Concrete:
- Incorporate in Bridge Decks: Self-healing concrete can be used in bridge decks to mitigate the effects of cracking caused by cyclic loading and environmental exposure.
- Highway Pavements: Application of self-healing concrete in highway pavements can reduce maintenance costs and extend the lifespan of roads, resulting in smoother and safer transportation networks.
- Tunnel Linings: Self-healing concrete provides enhanced protection for tunnel linings against water ingress and corrosion, ensuring the long-term integrity of underground structures.
Types of Self-healing Concrete
This concrete is of two types:
- Biotic concrete –Various bacteria are used as a catalyst in the crack healing process.
- Abiotic concrete– Various chemical compounds are used as a catalyst in the crack-healing process.
Methods of Self-healing Concrete
There are mainly two types of self-healing methods of concrete.
- Autogenous Self-healing method- Autogenic self-healing is a natural material-healing property, which initiates from the presence of generic materials in the concrete. The object of autogenic self-healing is the rehydration of un-hydrated cement in the concrete. The rate of Autogenic self-healing is much greater at an early age due to the presence of a high amount of un-hydrated cement and wet-dry cycles.
The method of autogenic self-healing can also be enhanced using fibers to restrict crack opening. The presence of a superplasticizer in the cement also enhances self-healing. - Autonomous Self-healing Concrete- In the autonomic self-healing system, encapsulated active healing agents are released into the concrete. Micro-vascular glass tube networks and microcapsules are the most popular encapsulation systems. The mobile liquid Healing agents used in this system should have a strong bonding ability between the crack faces.
Some of the most popular healing agents are alkali-silica solutions, methyl methacrylate, hydrogel, epoxy resins, and bacteria-based microorganisms.
Advantages of Self-healing Concrete:
- The biggest advantage of this concrete is that it increases the lifespan of the concrete structure.
- Self-healing technology decreases the maintenance of the concrete.
- Self-healing technology reduces the permeability of concrete.
- The possibility of corrosion of reinforced concrete is reduced in the case of self-healing concrete.
- This concrete improves the compressive strength of concrete compared to ordinary concrete.
Disadvantages of Self-healing Concrete
- This concrete is expensive compared to ordinary concrete. The cost of This concrete is almost double that of ordinary concrete.
- There is no standard code available for self-healing concrete.
- As this concrete, is a new product, only very few people have an idea of using it.
Self-healing concrete bacteria name
There are several types of bacteria that we can use in self-healing concrete.
Bacillus subtilis is a soil bacteria . It is able to survive in harsh environments. It produces spores that can remain dormant for long periods of time until they are needed to repair a crack in the concrete.
Bacillus sphaericus is another soil bacteria that has been used in self-healing concrete. It has the ability to produce calcium carbonate to seal cracks in the concrete.
Sporosarcina pasteurii is commonly used in biomineralization applications, including self-healing concrete. It can produce urease, which breaks down urea into ammonia and carbon dioxide. When it is used in self-healing concrete, the urease enzyme produces calcium carbonate to fill in cracks and restore the integrity of the concrete.
Future Scope of Self-healing Concrete
This concrete would be a total game-changer in the construction industry. This self-healing technology will give us the freedom to construct concrete structures without worrying about damages and intensive maintenance.
Testing of self-healing concrete
- Crack-healing efficiency test: This test determines the effectiveness of the self-healing mechanism in the concrete. The concrete is subjected to controlled cracking and then allowed to self-heal. The extent of crack closure and the durability of the healing is measured and analyzed.
- Water permeability test: This test is for determining the ability to prevent water ingress. The concrete is subjected to water pressure, and the rate of water penetration is measured and analyzed.
- Strength and stiffness tests: These tests determine the mechanical properties of self-healing concrete. The compressive strength, tensile strength, and stiffness of the concrete are measured and analyzed.
- Corrosion resistance test: This test is used to determine the ability of the self-healing concrete to resist corrosion caused by exposure to aggressive environments. The concrete is subjected to corrosive substances, and the extent of corrosion is measured and analyzed.
- Freeze-thaw resistance test: This test is used to determine the ability of the self-healing concrete to resist damage caused by freeze-thaw cycles. The concrete is subjected to cycles of freezing and thawing, and the extent of damage is measured and analyzed.
List out all the places where we can use self healing concrete
- Bridges and highways
- Tunnels and underground structures
- Buildings and infrastructure, such as dams, water tanks, and pipelines
- Marine structures, such as docks and piers
- Nuclear waste containers
- Architectural design
- Runways and airport aprons
- Wind turbine foundations
- Industrial flooring
- Retaining walls
- Seawalls and flood protection structures
- High-rise buildings
- Precast concrete structures
- Concrete pavements
- Concrete blocks and masonry units
FAQS on Self-healing Concrete
How long does self-healing concrete last?
This concrete can last up to 200 years because the healing agents can lie dormant for almost 200 years.
Is self-healing concrete expensive?
The cost of this concrete is considerably higher (almost double) than ordinary concrete.
How does self-healing concrete work?
Self-healing concrete contains microcapsules or vascular systems filled with healing agents. When cracks occur, these capsules rupture or the vascular systems release the healing agents, repairing the damage autonomously.
Is self-healing concrete expensive?
The cost of self-healing concrete is currently higher than traditional concrete due to the added technology and materials required. However, with advancements and increased adoption, costs are expected to decrease over time.
Can self-healing concrete be used in extreme climates?
Yes, self-healing concrete can be engineered to withstand extreme climates by using appropriate healing agents and protective measures during the construction process.
What are the long-term benefits of self-healing concrete?
Self-healing concrete significantly increases the lifespan of structures, reduces maintenance costs, and enhances structural integrity, resulting in long-term economic and environmental benefits.
Is self-healing concrete safe for the environment?
Yes, self-healing concrete contributes to environmental sustainability by reducing the need for extensive repairs and minimizing material waste, ultimately reducing the carbon footprint associated with infrastructure development.
Can self-healing concrete be used for historical restoration projects?
Self-healing concrete can be utilized for historical restoration projects to enhance the durability and longevity of heritage structures, preserving their architectural heritage.
How does self-healing concrete contribute to sustainability?
Self-healing concrete reduces the need for new construction, minimizes material waste, and extends the lifespan of infrastructure, aligning with the principles of sustainable development.
What are the challenges in implementing self-healing concrete on a large scale?
Challenges include the cost of production, logistics of large-scale implementation, and integration with existing construction practices. Continued research and development are crucial to overcome these challenges.
Are there any limitations to self-healing concrete?
Self-healing concrete’s limitations include initial higher costs, dependence on specific triggers, and the need for further advancements in large-scale implementation.
What are the future possibilities of self-healing concrete?
The future of self-healing concrete includes advancements in technology, integration with smart infrastructure, and the potential for real-time monitoring and predictive maintenance, revolutionizing the construction industry.
Conclusion
Self-healing concrete represents a groundbreaking innovation in the construction industry. With its ability to autonomously repair cracks and damage, this sustainable material enhances infrastructure durability, reduces maintenance costs, and contributes to environmental sustainability. Although challenges remain, ongoing research and development are propelling self-healing concrete towards a future where sustainable infrastructure is the norm. Embracing this technology will pave the way for a safer, longer-lasting, and more resilient built environment.