Self Healing Concrete

Short description about Self Healing Concrete

1. VVP POLYTECHNIC, SOLAPUR UNDER THE GUIDENCE OF– Prof. Sathe PRESENTED BY – Shidore Ganesh Rathod Vinayak SEMINAR ON – Self Healing Concrete (SHC)

2. CONTENT

3. DEFINITION – Self healing concrete is a concrete which heals itself when it comes in contact with air and water, it produces lime on outer layer of concrete. In most of the traditional concrete mixtures 20-30% of the cement is left unhydrated . If cracking of the concrete occurs, unreacted cement grains may become exposed to moisture penetrating the crack . In that case the hydration process may start again and hydration products may fill up and heal the crack. 1. INTRODUCTION

4. NECESSITY FORCES ON CONCRETE -

5. CONCRETE WITH REINFORCEMENT CONTINUE…

6. LIME FILLED IN CRACKS CONTINUE…

7. BACTERIA It contains an outer layer of thick wall, which resist sunlight, chemical exposure etc.

8. In 1877, Ferdinand Cohn claimed that with a bacteria known as “Genus Bacillus ” concrete could be healed. CONTINUE…

9. MIXING When spores fine aggregate, coarse aggregate and cement are mixed together, which results in Self H ealing Concrete. But while mixing one precaution is taken that bacteria and cement are not allowed to mix together with the help of clay pellets.

10. WORKING OF SELF HEALING CONCRETE Self-healing concrete is a product that will biologically produce limestone to heal cracks that appear on the surface of concrete structures. Ca(C3H5O2)2 + 7O2 → CaCO3 + 5CO2 + 5H2O ( Calcium Lactate) ( Lime) Specially selected types of the bacteria genus Bacillus, along with a calcium-based nutrient known as calcium lactate, and nitrogen and phosphorus, are added to the ingredients of the concrete when it is being mixed.

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12. TEST ON SELF HEALING CONCRETE HENK JONKERS In 2011, Jonkers and his team is doing testing and case study on self healing concrete. A small structure or part of a structure will be built with the self-healing material and observed over three to five years. Structures will be fitted with some panels of self-healing concrete and others with conventional concrete so that the behaviour of the two can be compared. Cracks will be made in the concrete that are much larger than the ones that have healed up in the laboratory to determine how well and fast they heal over time.

13. COMPARISON BETWEEN SHC AND ORDINARY CONCRETE

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15. ADVANTAGES

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17. Skilled labour are required. Concrete is costly. DISADVANTAGES

18. 1. Self healing epoxies can b e incorporated on the metals to prevent corrosion. 2. Self healing is used on structure to prevent cracks on concrete. APPLICATIONS

19. CONCLUSION Hence, self healing concrete is crack resistant. W hich protects the concrete and reinforcement from cracks and from corrosion. By doing this, it prevents water to percolate into reinforced steel concrete and hence it does not comes in contact with reinforcements. Thus, it prevents reinforcement from corrosion. It is a research project.

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