BACTERIAL BASED SELF HEALING CONCRETE

1. G M INSTITUTE OF TECHNOLOGY, DAVANAGERE
Department Of Civil Engineering.
2017 – 2018
Presented by:
NIKHIL S
4GM14CV028
BACTERIAL BASED SELF-HEALING
CONCRETE

2. CONTENTS
INTRODUCTION
BACTERIAL CONCRETE
BACTERIA USED
CHARACTERISTICS OF BACTERIA
CULTURING AND MIXING OF BACTERIAL CONCRETE
MACHANISM OF HEALING
CHEMICAL REACTION
APPLICATION
ADVANTAGES & DISADVANTAGES
CONCLUSION
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3. INTRODUCTION
• Cracks in concrete formed due to various reasons which allows chemicals and water to
enter ,and causes corrosion of reinforcement and finally leads to failure of structure.
• There are different methods for prevention and control of cracks , bacterial concrete is
one of them.
• The bacteria’s which are added to concrete and makes the concrete which can repair
itself without human work called Bacterial based self healing concrete.
• Bacteria’s added with soluble calcium lactate (feed) which convert invert into insoluble
crystals of calcium carbonate , when exposed to atmosphere.
• Which seals the cracks and makes the concrete impermeable.
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4. BACTERIAL CONCRETE
• The principle of the concrete is “Bio mineralization” , precipitation of crystal by using
bacteria.
• Bacteria’s mixed with concrete at the time of mixing and they remain hibernated for 200
years.
• Gets activated when exposed to water or moisture.
• The concrete is high in alkalinity and pH varies from 8-9 ,the bacteria’s used should be
able to sustain alkaline environment.
• Bacillus group of bacteria’s are common soil bacterium and able to sustain high alkaline
and harsh environment.
• These bacteria’s able to precipitate calcite crystals.
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5. TYPES OF BACILLUS BACTERIA’S
There are different types bacteria’s are listed below
• Bacillus pasteurii
• Bacillus subtilis
• Bacillus sphaericus
• Bacillus cohnii
• Bacillus pseudofirmus
Bacillus pasteurii is most commonly used soil bacteria in concrete.
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6. BACTERIA USED
Bacillus pasteurii
Animated images Bacillus pasteurii diagram
Microscopic images of Bacillus
pasteurii

7. Characteristics Bacillus Pasteurii
• Single celled organisms.
• Commonly available in all type of soils.
• Doesn’t cause any harm to human.
• Long rods, 0.6-0.8 μm in width and 2.0 to 3.0 μm in length.
• Doesn’t react with other ingredients of the concrete .
• Susceptible to high alkaline environment (cultured bacteria up to
13).
• Heals up to 0.4 mm wide cracks.
• Suitable for all type of concrete.
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8. Culturing & mixing bacteria concrete
• Primarily 12.5 gm. of nutrient (calcium lactate) is added to a 500ml conical
flask containing distilled water.
• It is than covered with thin cotton plug and made it as airtight.
• It is than sterilized using cooker for about 10-20 minutes , now the solution
is free from any contaminants and clear orange solution is obtained.
• Later the flask is opened up and exactly 1 ml of bacterium is added to the
sterilized flask and kept shake at a speed of 150-200 rpm overnight.
• After 24 hours the bacterium solution was found to be yellow turbid
solution with bacteria having cell concentration of 105 cells per ml.
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9. BACTERIAL SOLUTION
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Incubator Bacterial solution

10. MACHANISM OF SELF HEALING
• When the cracks develops it allows water and moisture content into the concrete
• As soon as the water enters the concrete through cracks ,the bacteria’s become active and it start
feeding the calcium lactate and absorbs the oxygen from water or moisture and start precipitating the
insoluble crystals of calcium carbonate ( lime stone ) and seals the cracks
• When the cracks completely filled and again bacteria’s goes to hibernate.
• In the favourable environment it takes around 2 weeks to completely heal a crack width of 0.4mm.
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13. Healing progress shown in SEM
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14. Healing shown in microscope
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15. Chemical reaction
• As the bacteria feeds oxygen is consumed and the soluble calcium lactate is
converted to insoluble limestone.
• The limestone solidifies on the cracked surface, thereby sealing it up.
• Tests all show that bacteria embedded concrete has lower water and chloride
permeability by 88%
• Reaction:
• Ca(C3H5O2)2 + 7O2 → CaCO3 + 5O2 +5H2O
(Calcium lactate)
• The crystals expand until the entire gap is filled.
• The extra molecule of water again continuous the reaction.
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16. Results by Research papers
Strength Study
Tests on M30 concrete
Conventional Concrete Bio Concrete
7 days 28 days 7 days 28 days
Compressive Strength 20.85 30.00 27.10 38.95
Split Tensile Strength 3.26 4.51 3.93 5.13
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Results in (Mpa) for Concrete and bacteria cell concentration 10^5/ml
mixing water

17. SEM images for cell concentration
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19. Application
• Used in underwater structure
• Used in water Bearing structure
• Used in under ground structures
• Used in pre cast members
• Used for all types of concrete works
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20. ADVANTAGES
• Concrete become impermeable .
• Repairs without a human work.
• Self-healing concrete also prevents the exposure of the internal reinforcements.
• It has made to extend the life span of a concrete structure of any size, shape.
• Increase the strength of the concrete.
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21. DIS ADVANTAGES
• Cost of construction more.
• Skilled labour required.
• Bacterial culture required.
• It is still developing technology.
• Accuracy in mixing and culturing.
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22. Conclusion
• Microbial mineral precipitation resulting improve the overall behaviour of
concrete.
• The greatest improvement in compressive strength occurs at cell concentrations of
10^5 cells/ml mixing water.
• The study result shows that increase in compressive strength of concrete.
• Less permeability and corrosion resistance.
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23. References
• Ramachandran S.K., Ramakrishnan V. and Bang S.S., Remediation of concrete using
microorganisms, ACI Materials Journal 98(1), 3-9 (2001)
• S. SUNIL PRATAP REDDY International Journal of Earth Sciences and Engineering ISSN 0974-
5904, Vol. 03, No. 01, February 2010, pp. 116-124.
• Chintalapudi Karthik, Rama Mohan Rao.P. Properties of Bacterial-Based Self-healing concrete,
International journal of chem tech Research (2016) vol.9, No.02 pp182-188.
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24. • Navneethchahal, Rafat Siddique, Anitha Rajar (2012). “Influence of
Bacteria on the compressive strength, water absorption of the concrete”,
Asian journal of Civil Engineering, Vol 1, No 1, 43-55.
• Abhijit Sing Parmar, Ankit Patel (2013),”Improvement on the concrete
cracks by using Bacillus Pasteurii”, International journal for Scientific
Research & Development, Vol 1, Issue 1.
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25. Thank You