Self healing concrete bacterial concrete and biological concrete

1. DARBHNGA COLLEGE OF ENGINEERING,DARBHANGA
Department of Civil Engineering
Presentation on
Self Healing Bacterial Concrete
Present by:
Raja Kumar , Kr Subhendu Shubham & Prince kumar
18101111031 18101111007 & 18101111056

2. CONTENT
INTRODUCTION
SELF HEALING CONCRETE
BACTERIA
CHARECTERSTICS OF BACTERIA
BIO CONCRETE MICANISM
CHEMICAL REATION
APPLICATION
ADVANTANGE AND DISADVANTRAGE
CONCLUSION

3. INTRODUCTION
CONCRETE:
• it is the most widely used material for the construction. Concrete is
weak in tension and strong in compression and cracks are inevitable in
concrete. Once cracks form in concrete it may reduce the lifespan of
the concrete structures.

4. SELF HEALING CONCRETE
 Self healing concrete is a concrete which heals it self when it comes in contact
with air and water. It produced 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 grins may become Exposed
to moisture penetrating the crack.
 In that case the Hydration process may start again and Hyration process may fill
up and Heal the crack.
 Self Healing concrete is also known as Bio concrete
 Self healing concrete is a product that will Biologically produce Limestoneto heal
cracks that appear on the surface of concrete structures.

5. BACTRIA
 In 1877, FERDINAND COHN climed that with a Bacteria known as
“GENUS BACILLUS” Concrete could be healed.
 It contains an outer Layer of thick wall, which Resist sunlight chemical exposure etc.
 Mixing: When spores fine aggregate, coarse aggregate and cement are mixed together,
which results in self healing concrete.But while mixing one precaution is taken that
Bacteria and cement are not allowed to mix together with the help of CALY PELLETS.
• Cement and water have a very high pH value of around 13 when it mixed together. In such
high pH environment most micro-organisms die. The bacteria which need to be added
should fit such special norms i.e., it should be alkali resistant and it should also be able to
withstand the harsh environmental conditions of the concrete.

6.  Specially selected types of the bacteria GENUS BACILLUS, along with a calcium –
Based nutrient known as calcium Lactate, and Nitrogen and Phosporus are added to
the ingredients of the concrete when it is being mixed
 There are moderate techniques to repair the cracks in concrete by itself called Self-
Healing Concrete. This bacterial remediation technique surpasses other techniques as
it is bio-based, eco-friendly, cost-effective and durable.
 Concrete is a highly alkaline material, the bacteria added is capable of withstanding
alkali environment. Bacteria with calcium nutrient source are added into the concrete
at the time of mixing. If any cracks will be formed in concrete, bacteria precipitate
calcium carbonate. This will seal the cracks.

7. TYPES OF BACTERIA
There are different types of bacteria and spores below
I. Bacillus megaterium
II. Bacillus pasteurii
III. Bacillus subtilis
IV. Bacillus aerius
V. Sporosarcina pasteurii
VI. Bacillus cohnii
Bacullus pasteurii most commonly used soil bacteria in concrete

8. BACTERIAL SOULTION

9. BACTERIA USED

10. CHARECTERISTICS of BACILLUS PASTEURII
 Single celled organisms.
 Commonly available in all type of soil
 Doesn’t react with other ingredients of the concrete.
 Susceptible to high alkaline environment (cultured bacteria up to
130).
 Heals up to 0.4 mm wide cracks.
 Suitable for all type of concrete.

11. BIO CONCRETE MECANISM
 In self-healing concrete, ingredient is mixed with
bacterial water replacing potable water. Bacterial
water has a concentration of 105 cells of Bacillus
megaterium per ml of water. The bacterium goes
into dormant state, when cracks occur in future by
obvious reason, the bacteria get exposed to the air
and water and they start precipitating calcite
crystals.

12. MACHANISM OF SELF HEALING

13. CHEMICAL REATION

16. HEALING SHOWN IN MICROSCOPE

18. APPLICATION

19. ADVANTAGE
• The use of self-healing concrete significantly enhances the strength of concrete.
• It has lower permeability when compared to conventional concrete.
• Repair without human work.
• It has also lower water absorption when compared to conventional concrete.
• It offers great resistance against freeze and thaw attacks.
• The chances of corrosion of reinforcement are reduced to negligible.
• Redressing of cracks can be done efficiently.
• Overall maintenance cost of this concrete is low

20. DISADVANTAGE
•  There is no design of bacterial concrete is mentioned in IS codes or any other codes.
•  Cost of this concrete is comparatively higher than conventional concrete; it’s about 10-30% more than conventional concrete.
•  The germination of bacteria is not suitable in every environment.
•  The investigations involved to observe calcite precipitation are costly.
•  Bacteria that are used in concrete are not good for human health; hence its usage should be limited to the structure.
• Application of Bacterial concrete:
• Self healing bacterial concrete can be used for sectors such as tunnel-lining, structural basement walls, highway bridges, concrete floors and
marine structure.
•

21. CONCLUSION
• Microbial mineral precipitation resulting improve the overall
behaviour of concrete.
• The greatest improvement in compressive strength occurs at cell
concentrations of 125 cells/ml mixing water.
• The studu result shows that increase in compressive strength of
concrete
• Less permeability and corrosion resistance.

22. REFERANCES