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0204SelfHealing.pdf

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Self-healing concrete is a concrete that repairs cracks through a biological reaction caused by bacteria in the concrete. When cracks form and air and water enter, bacteria produce limestone to fill the cracks. This allows the concrete to heal itself over time. The bacteria remain dormant for over 200 years but become active when cracks form. Self-healing concrete improves durability and reduces corrosion compared to normal concrete, though it has 20% lower strength and higher costs. Potential applications include tunnels, bridges, and marine structures.

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SELF HEALING CONCRETE 43
Self Healing Concrete Self Healing Concrete (SHC) is a concrete which heals itself by repairing cracks with the help of bacteria when it comes in contact with air and water. It produces lime on outer layer of concrete. • Filling of the cracks is a biological reaction or in other words, a product i.e, limestone is produced within the concrete with the help of bacteria and after hardening it fills the crack known as self healing of concrete. • The bacteria which is present inside the concrete will be in a dormant state for over 200 years under dry conditions and when there will be a crack, moisture enters inside the concrete, and bacteria act as a catalyst in the process of crack healing. 44
Self Healing Concrete • Self Healing Concrete (SHC) is also known as “Bio Concrete” or “Bacterial Concrete”. • It improves the durability of concrete by its self healing property. Properties of SHC: 1. Compressive strength 2. Tensile strength and 3. Flexural strength Advantages of SHC: 1. Self-healing concrete is an effective method for sealing off cracks in the infrastructures. 2. Reduction in the corrosion of steel reinforcements inside the concrete 45
Self Healing Concrete 3. Increases the moisture impermeability. 4. It is an eco-friendly technique reducing carbon dioxide emission. 5. It is a revolutionary concept promising better future for concrete exhibiting additional strength and durability to the structure, especially where preservation of monuments are concerned. Disadvantages of SHC: 1. The clay particles used in the self-healing concrete occupy about 20% of the total volume of the concrete by replacing the normal aggregate thus reducing compressive strength to about 20-25%. 2. The concrete at present, cannot be used for the construction of sky-scrappers, however with the further advancement in the technique, one can overcome this problem. 3. The cost of bacterial concrete is double that of conventional concrete. 4. The growth of the bacteria is not the same in all weather conditions and media. 46
Self Healing Concrete 5. Design Standards of self healing of concrete are not available in any IS codes or other code. 6. The investigation is costlier and time-consuming. Applications of SHC: 1. It can be used for sectors such as tunnel lining, structural basement walls, highways, bridges, concrete floor and marine structures. 2. Durable road construction. 3. High strength buildings with more bearing capacity. 4. Long lasting river banks. 5. Erosion prevention of loose sands. 6. In the production of bricks. 47
Self Healing Concrete BACTERIA 48
Self Healing Concrete BACTERIA 49
Self Healing Concrete 50
Self Healing Concrete 51
Self Healing Concrete 5. Design Standards of self healing of concrete are not available in any IS codes or other code. 6. The investigation is costlier and time-consuming. Applications of SHC: 1. It can be used for sectors such as tunnel lining, structural basement walls, highways, bridges, concrete floor and marine structures. 2. Durable road construction. 3. High strength buildings with more bearing capacity. 4. Long lasting river banks. 5. Erosion prevention of loose sands. 6. In the production of bricks. 52
Self Healing Concrete Questions 1. What is self healing concrete? Explain its mechanism. 2. What are the advantages and disadvantages of SHC? 3. Mention the properties of SHC. 4. Mention applications of SHC 53

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0204SelfHealing.pdf

  • 2. Self Healing Concrete Self Healing Concrete (SHC) is a concrete which heals itself by repairing cracks with the help of bacteria when it comes in contact with air and water. It produces lime on outer layer of concrete. • Filling of the cracks is a biological reaction or in other words, a product i.e, limestone is produced within the concrete with the help of bacteria and after hardening it fills the crack known as self healing of concrete. • The bacteria which is present inside the concrete will be in a dormant state for over 200 years under dry conditions and when there will be a crack, moisture enters inside the concrete, and bacteria act as a catalyst in the process of crack healing. 44
  • 3. Self Healing Concrete • Self Healing Concrete (SHC) is also known as “Bio Concrete” or “Bacterial Concrete”. • It improves the durability of concrete by its self healing property. Properties of SHC: 1. Compressive strength 2. Tensile strength and 3. Flexural strength Advantages of SHC: 1. Self-healing concrete is an effective method for sealing off cracks in the infrastructures. 2. Reduction in the corrosion of steel reinforcements inside the concrete 45
  • 4. Self Healing Concrete 3. Increases the moisture impermeability. 4. It is an eco-friendly technique reducing carbon dioxide emission. 5. It is a revolutionary concept promising better future for concrete exhibiting additional strength and durability to the structure, especially where preservation of monuments are concerned. Disadvantages of SHC: 1. The clay particles used in the self-healing concrete occupy about 20% of the total volume of the concrete by replacing the normal aggregate thus reducing compressive strength to about 20-25%. 2. The concrete at present, cannot be used for the construction of sky-scrappers, however with the further advancement in the technique, one can overcome this problem. 3. The cost of bacterial concrete is double that of conventional concrete. 4. The growth of the bacteria is not the same in all weather conditions and media. 46
  • 5. Self Healing Concrete 5. Design Standards of self healing of concrete are not available in any IS codes or other code. 6. The investigation is costlier and time-consuming. Applications of SHC: 1. It can be used for sectors such as tunnel lining, structural basement walls, highways, bridges, concrete floor and marine structures. 2. Durable road construction. 3. High strength buildings with more bearing capacity. 4. Long lasting river banks. 5. Erosion prevention of loose sands. 6. In the production of bricks. 47
  • 10. Self Healing Concrete 5. Design Standards of self healing of concrete are not available in any IS codes or other code. 6. The investigation is costlier and time-consuming. Applications of SHC: 1. It can be used for sectors such as tunnel lining, structural basement walls, highways, bridges, concrete floor and marine structures. 2. Durable road construction. 3. High strength buildings with more bearing capacity. 4. Long lasting river banks. 5. Erosion prevention of loose sands. 6. In the production of bricks. 52
  • 11. Self Healing Concrete Questions 1. What is self healing concrete? Explain its mechanism. 2. What are the advantages and disadvantages of SHC? 3. Mention the properties of SHC. 4. Mention applications of SHC 53