2. INTRODUCTION
BACTERIAL CONCREATE
BACTERIA USED
CHARACTERISTIC OF BACTERIA
MIXING OF BACTERIAL CONCREATE
MECHANISM OF HEALING
CHEMICAL REACTION
APPLICATION
ADVANTAGES AND DISADVANDAGES
CONCLUSION
REFERENCE
3. Cracks in concreate is formed due to various reasons which allows chemical and water to enter, and causes
corrosion of reinforcement and finally leads to failure of structures.
There are different methods for prevention and controls of cracks, bacterial concreate is one of them.
The bacterial 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 it into insoluble crystals
of calcium carbonate, when exposed to atmosphere.
Which seals the cracks and makes the concreate impermeable
4. The principle of the concrete is “Bio mineralization”, precipitation of crystal by using bacterial.
Bacteria’s mixed with concrete at the time 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 bacteias used should be able to sustain
alkaline environment.
These bacteria‘s able to precipitate calcite crystals.
5. Various bacteria used in the production
of bacterial concrete are.
• Bacillus pasteurizing
• Lysinibacillus sphaericus
• Escherichia coli
• Bacillus subtilis
• Bacillus cohnii
• Bacillus halodurans
• Bacillus pseudofirmus
6. Single celled organism.
Commonly available in all type of soil.
Doesn’t cause any harm to human.
Doesn’t react with other ingrediantsof the concrete.
Susceptible to high alkline environment.
Suitable for all type of concrete.
7. Bacterial concrete is prepared in two ways;
1. By direct application method.
2. By encapsulation method.
By direct application method:
In this direct method, the bacterial spores and calcium lactate are directly added into the concrete after the
mixing process.
By encapsulation method:
In this method, the bacterial spores and calcium lactate are placed together in clay pellets and these are
mixed in the concrete at 6% of the total concrete mixture.
8. 01
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 become active and it start
feeding the calcium lactate and absorbs the oxygen water or moisture and start precipitating the
insoluble crystals of calcium carbonate and seals the cracks.
When the cracks completely filled and again bacteria goes to hibernate.
It takes around two weeks to complete heal a crack width of 0.4 mm.
9. • As bacteria feeds oxygen is consumed and the soluble calcium lactate is converted to insoluble
limestone.
• The limestone solidifies on the cracked surface, thereby sealing itup.
• Tests all shows that bacteria embedded concrete has lower water and chloride permeablity by 88%.
• Reactin : Ca(C3H5O2)2+7O2 ~ CaCO3+5O2+5H20
• The crystal expand until the entire gap is filled.
10. Used in under water structure.
Used in water bearing structures.
Used in under ground structures.
Used in pre cast members.
Used for all type of concrete works.
11. • Self-repairing of concrete without any external applications.
• The flexural strength and compressive strength of self healing concrete are greater than the normal
concrete.
• The permeability of concrete is reduced.
• It also reduces the corrosion of steel reinforcement and improves durability.
• Bacillus bacteria are harmless and can be used for the repairing of the concrete.
• Cost of construction more.
• Skilled labour required.
• Bacterial culture required.
• Accuracy in mixing and culturing.
12. From these studies, it is clear that we can implement this
technology to improve the properties of concrete.
When we compare the cost with sustainability, for long term
solution, the self healing of concrete is dominating the
conventional one.
In the future, self healing concrete is going to revolutionize the
construction industry.
13. • Ramachandran SK, Ramakrishnan v. And Bang SS, Remediation of concrete using micro
organism ACI material journal 98 ( 1 ) , 3-9(2001)
• S SUNIL PRATAP REDDY international journal of earth science and engineering ISSN 0974-5904
VOL, 03,NO0l, February 2010,pp 116-124.
• Chintalpudi karthik, rama mohan rao properties of Bacterial-based self healing concrete,
international journal of chemical tech research (2016) vol9 pp 182-188.
• Ability sing parmar, ankit patel (2013) , "improvement on the concrete cracks by using Bacillus
pasteruii", international journal for scientific research & development, vol 1 issue 1 .
