Cracks in concrete are inevitable and are one of the inherent weaknesses of concrete. Water and other salts seep through these cracks, corrosion initiates, and thus reduces the life of concrete. So there was a need to develop an inherent biomaterial, a self - repairing material which can remediate the cracks and fissures in concrete. Bacterial concrete is a material, which can successfully remediate cracks in concrete. This technique is highly desirable because the mineral precipitation induced as a result of microbial activities is pollution free and natural. As the cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of the wall is substantial, thus the entire cell becomes crystalline and they eventually plug the pores and cracks in concrete. This paper discusses the plugging of artificially cracked cement mortar using Bacillus Pasteurii bacteria combined with sand as a filling material in artificially made cuts in cement mortar which was cured in urea and Calcium chloride medium. The effect on the compressive strength and stiffness of the cement mortar cubes due to the mixing of bacteria is also discussed in this paper. It was found that use of bacteria improves the stiffness and compressive strength of concrete. Scanning electron microscope (SEM) is used to document the role of bacteria in microbiologically induced mineral precipitation. Rod like impressions were found on the face of calcite crystals indicating the presence of bacteria in those places. In this study, bacterial concrete is to be prepared under grade of concrete OPC 43.The design mix proportioning also carried under IS code provision. Testing of specimens are carried at 7 days ,14 days and 28 days of curing by Compression Testing Machine and Universal Testing Machine for corresponding specimens. The Compressive Strength and Flexural Strength of Bacterial Concrete are found.

1. Welcome to the Seminar on
“Bacterial concrete”
A Remedial Measure For Micro-cracks in Concrete
Presentation By,
Ajeet S Panedakatti
(2GI13CV705)
Guided By,
Prof. R.B.Kulkarni
Civil Engineering Department, KLS
Git ,

2. contentS
1.Introduction
2.Bacterial concrete
3.Classification of bacteria
4.Literature study
5.Case study
6.Bacterial growth curve
7.Tests on bacterial concrete
8.Application in construction

3. 9.Current searches
10.Scanning electron microscopy examination
11.Conclusion
References

4. abStract
 Cracks in concrete are inevitable and are one of the inherent weaknesses of
concrete. Water and other salts seep through these cracks, corrosion initiates,
and thus reduces the life of concrete. So there was a need to develop an
inherent biomaterial, a self - repairing material which can remediate the cracks
and fissures in concrete.
 Bacterial concrete is a material, which can successfully remediate cracks in
concrete. This technique is highly desirable because the mineral precipitation
induced as a result of microbial activities is pollution free and natural.
 This paper discusses the plugging of artificially cracked cement mortar using
Bacillus Pasteurii bacteria combined with sand as a filling material in
artificially made cuts in cement mortar which was cured in urea and Calcium
chloride medium.

5. 1.introDUction
 Cracks in Concrete
1.Concrete is a building material that is an absolutely essential
component of public infrastructure and buildings.
2. It is most effective when reinforced by steel rebar, mainly because its
tensile strength without reinforcement is considerably low relative to
its compressive strength.
3. Concrete is also a very brittle material with low tolerance for strain,
so it is commonly expected to crack with time.
4. Cracks expose the steel reinforcement to the elements, leading to
corrosion which heightens maintenance costs and compromises
structural integrity over long periods of time.

6. introDUction (continUeD)
5. Concrete cracks and suffers serious wear and tear over the decades
of its expected term of service.
6. Concrete is not flexible and cannot handle significant amounts of
strain.
7. Self-healing concrete in general seeks to rectify these flaws in order
to extend the service life of any given concrete structure.
8. Rapid growth and development in the infrastructure can be seen
over the past hundred years in the construction activities. In this
development concrete plays an important role in the development of
the infrastructure in the day-to-day life.

7. 2.bacterial concrete
1. In order to heal the cracks in bacteria, autogenous self-healing
techniques are adopted by embedding bacteria and healing agent to
precipitate calcium carbonate on the freshly formed micro-cracks.
The precipitation of calcite by continuous hydration of cement
helps in production of calcium carbonate precipitation with the help
of urease producing bacteria.
2. The influence of ureolytic bacteria “Bacillus pasteurii” on
concrete helps in calcite formation by continuous hydration of
cement in concrete.
3. The bacteria used are capable of precipitating calcite by
producing urea with the help of calcium source. The bacteria are
added at the time of mixing process of concrete along with calcium
sources, nitrogenous and phosphate ingridients .

8. 3.claSSification of bacteria

9. The Bacteria Can be classified based on three categories
1. Based on shape
Bacilli,
Spirilla ,
Cocci.
2. Based on gram strain
Gram positive
Gram negative
3. Based on survival in atmosphere
Aerobic and anaerobic

10. 4.LITERATURE SURVEY
1. Chintalapudi kartik et all : Carried the work on the bacterial
concrete, the addition of urease producing bacteria along with
calcium source results in calcite precipitation in concrete.
Experiments showed that the cell concentrations of 106 cells/ml of
water in the cement paste and mortar specimens has higher
compressive strength gain was up to 39.8% , 33.07% and 50% ,
28.2% respectively.
2. S Siddiraju et all:In the self -healing of concrete technique
ureolytic bacteria are used, hence the concrete is called Bacterial
concrete. The percentages of bacteria selected for the study are
3.5% and 5% by weight of cement. In addition, calcium lactate was
used at 5% and 10% replacement of cement by weight.

11. .
3. Amudhavalli et all : Carried work on the bacteria such as
Bacillus Pasteuri, Bacillus megaterium, Bacillus subtilis which
are having some disadvantages and also Pseudomonas
aeruginosa are undoubtedly pathogen and cannot be directly
applied in building structures like houses and offices because
of health concerns.

12. 5.CASE STUDY
PROPERTIES OF BACTERIAL BASED SELF
HEALING CONCRETE
Chintalapudi kartik, Rama Mohan Rao.P, (2016)
In the case study it is discussed that, the addition of urease
producing bacteria along with calcium source results in calcite
precipitation in concrete. The ureolytic bacteria” Bacillus
pasteurii” which can produce urea is added along with the
healing agent to seal the freshly formed micro-cracks by
calcium carbonate precipitation. Experiments showed that the
cell concentrations of 106 cells/ml of water in the cement
paste and mortar specimens has higher compressive strength
gain was up to 39.8% , 33.07% and 50% , 28.2% respectively.

13. METhoDoLogY
Materials used
1. Cement :
OPC-43 grade cement. Normal consistency of cement is 32% nd
specific gravity is 3.08.
2. Coarse and fine aggregates :
Crushed granite stones is used as coarse aggregates, specific gravity
is 2.95.Fine aggregates having specific gravity of 2.69.
Fine aggregates confirming to IS 383:1970.Fine aggregates are free
from dust when used in concrete.

14. Bacteria used
Name Bacillus Pasturii
Shape Rod shaped-9 Micron meters
Density 10,00,000 spores per gram
Function Enzyme production
Order Bacillales

15. Preparation of bacterial solution
1. Primarily 12.5g of Nutrient broth (media) is added to a 500ml
conical flask containing distilled water.
2. It is then covered with a thick cotton plug and is made air tight
with paper and rubber band.
3. It is then sterilized using a cooker for about 10-20 minutes. Now
the solution is free from any contaminants and the solution is clear
orange in color before the addition of the bacteria.
4. Later, the flasks are opened up and an exactly 1ml of the
bacterium is added to the sterilized flask and is kept in a shaker at a
speed of 150- 200 rpm overnight.
5. After 24 hours the bacterial solution was found to be whitish
yellow turbid solution.

16. 6.BACTERIAL gRoWTh CURVE

17. Stationary phase: During this stage, the number of cells undergoing division is equal to the
number of cells that are dying. There is no further increase in cell number and the population
is maintained at its maximum level for a period of time. The primary factors responsible for
this phase are the depletion of some essential metabolites and the accumulation of toxic acidic
or alkaline end products in the medium.
• Decline or death phase: Because of the continuing depletion of nutrients and buildup of
metabolic wastes, the microorganisms die at a rapid and uniform rate. This decrease in
population closely parallels its increase during the log phase. Theoretically, the entire
population should die during a time interval equal to that of the log phase. This does not
occur, however, since a small number of highly resistant organisms persist for an
indeterminate length of time.

18. Bacterial growth curve

19. Chemical process to remediate cracks by bacteria
Crack –penetrating water would not only dissolve calcite (CaCO3)
particles present in mortar matrix ,but would also react together
with atmospheric carbon dioxide with not fully hydrated lime
constituents such as calcium oxide and calcium hydroxide according
to the following reactions.
The freshly produced minerals from the above stated reactions and
from dissolved and re-crystallized calcite mineral, precipitated on
the surface of cracks what resulted in crack-sealing and concomitant
reduction in permeability of the mortar.

20. 7.Tests on bacterial concrete
1. Compression strength test:
The cube of size 15X15X15 cm was used for the test.
The inner surface of cubes was applied with light coat oil. The dust
free coarse, fine aggregates and the cement was mixed in a
mechanical mixture, to the dry mix calculated quantity of water
along with bacteria was added to the dry mix, such that a uniform
colour of concrete is formed. The concrete cubes were tested after
28 days curing.

21. 2.Flexural strength test :
The beam of size 10X10X50 cm was used for the test.
The inner surface of beams was applied with light coat oil. The
dust free coarse, fine aggregates and the cement was mixed in a
mechanical mixture, to the dry mix calculated quantity of water
along with bacteria was added to the dry mix, such that a uniform
colour of concrete is formed. The concrete beams were tested after
28 days curing.

22. Test Results
Compressive and flexural strength test result for 7
and 28 days

24. 8.Application in construction

25. 9.Current Searches
Marine structures Underground constructions

26. 10.Scanning electron microscopy
examination
SEM forbio concrete shows that more denseinmicro structures ascompare to
conventional concrete,which implies thatitenhance strength tothe concrete

27. Conclusions
1. Bacterial concrete technology has proved to be better than many
conventional technologies because of its eco- friendly nature, self-
healing abilities and increase in durability of various building
materials.
2. Work of various researchers has improved our understanding on
the possibilities and limitations of biotechnological applications on
building materials.
3. The application of bacterial concrete to construction may also
simplify some of the existing construction processes and
revolutionize the ways of new construction processes.
4. Bacterial concrete, primarily reduce the maintenance costs, repair
costs and hence results in increase of durability of the structures.

28. Reference
1. Chintalapudi kartik, Rama Mohan Rao.P, (2016), “Properties of
Bacterial-based Self-healing Concrete”, International Journal of
Chemical Tech Research, Vol.9, No.02, Page no: 182-188.
2. Emily Adelsohn, John Hartsock,(2007),”Bacteria Infused self-
healing concrete”, International Journal of Chemical Tech Research,
Vol.81, No.12, Page no:89-112.
3. Abhijit Mandlik , Sharique Anwar, MD Zeeshan, Manish Chavan,
Parvin Gorde ,(2015) , “A Review Of Bacterial Concrete as an
application in Construction” , International Journal of Chemical
Tech Research , Vol.3, Issue-6, Page no:76-115.

29. 4. Dr S Siddiraju, N Ganesh, (2015), “Behavior of Bacterial
concrete”, International Journal of Science and Research, Vol.17,
No.18, Page no: 115-189.
5. Amudhavalli.N.K, Keerthana.K, Ranjani.A, (2015),”Experimental
Study on Bacterial Concrete”, International Journal Scientific
engineering, Volume-1, Issue-8.
6. Mayur Shantilal Vekariya, Prof. Jayeshkumar Pitroda , (2013),
“Bacterial Concrete: New Era For Construction Industry”,
International Journal of Engineering Trends and Technology,
Volume 4, Issue 9- Sep 2013.