New Construction Technology - Self-Healing Concrete to Repair Cracks
Concrete is the most significant building material used in construction which can withstand compressive forces but not tensile forces. Due to low tensile strength, it begins to crack when it is subjected to tension. This is why it is steel-reinforced to withstand tensile forces. Because of its comparatively low tensile strength, cracks in concrete are a common phenomenon. Such cracks impair the durability of concrete since they offer a convenient route for the transport of liquids and gases that potentially contain dangerous substances. If micro-cracks expand and reach the reinforcement, it is not only possible to attack the concrete itself, but it can also corrode the reinforcement. Thus, it is important to monitor the width of the crack and to heal the cracks as soon as possible. Since the costs involved in the maintenance and repair of concrete structures are generally high, the focus of this research is on the development of concrete for self-healing.
What is self-healing Concrete?
A material of self-healing is described as a material capable of repairing itself back to its original state. Self-healing Concrete is also referred to as “Bio-Concrete” & “Bacterial Concrete”. Self-healing concrete cracks will allow concrete structures to have a longer service life and not only make the material more durable but also more sustainable.
How does it Work?
This concrete consists of a special form of bacteria genus Bacillus along with ingredients such as calcium lactate, nitrogen, and phosphorus. For up to 200 years, these bacteria can sleep in the concrete.
The bacteria will increase and multiply when the water drops into the structure if the concrete structure gets damaged. They consume oxygen and begin feeding on the calcium lactate once the bacteria are awakened, and convert soluble calcium lactate into insoluble limestone. The limestone generated compresses the cracked surface and seals it.
- Helps to fill the cracks.
- Improvement in compressive strength of concrete.
- Helps to reduce maintenance and repair.
- Reduction in the permeability of concrete.
- Reduction in corrosion of reinforced concrete.
- Better resistance against freeze-thaw attack reduction.
- The cost of concrete for self-healing is double
than that of conventional concrete.
- Skilled labour is required.
- The growth of any bacteria in any atmosphere media is not good.
- Analysis of calcite precipitation is an expensive study.
- For sectors such as bridges, highways, structural basement
walls, tunnel-lining, concrete floors & marine structures, self-healing
concrete can be used.
- This is a revolutionary technology that can provide durable
- High strength structures with more bearing capacity.
- Erosion prevention of loose sands.
- Long-lasting river banks.
it is still being developed, this type of concrete is used on a limited scale
and is not yet commercially common. Cost and development are some of the major
Effects on Architecture & Design: Architects need to re-consider design standers-by increasing the lifespan of a building. The design of any building is affected by a long life-span, as architects must take into consideration the future prognosis of two key aspects:
- The potential function within a specific building (potential technological needs, change of function, change of lifestyle, etc.)
- The future function of the urban space that surrounds a certain house. Therefore, the key challenge of architects is to foresee the future needs and the current ones to design and create a useful, aesthetic, and most importantly, highly versatile building in order to quickly change function.
Environmental impact: One of the two main producers of carbon dioxide (CO2) pollution is the cement industry, which is directly damaging our world. Therefore, carbon dioxide emissions are reduced significantly by using SHC.
- Hence, self-healing concrete is crack resistant. Which protects the Concrete & Reinforcement from cracks & corrosion.
- By doing this, it prevents water to percolate into reinforced steel concrete & hence it does not comes in contact with reinforcements. Thus, it prevents reinforcement from corrosion.
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