This document discusses bacterial concrete, a self-repairing biomaterial. It begins by introducing the concept and challenges with existing concrete repair methods. Bacterial concrete uses bio-mineralization processes where bacteria form inorganic solids either inside or outside the cell. Four types of bacteria - B. Pasturii, B. Subtiles, B. Sphaericus, and B. Cohnii - are classified and their activation mechanisms described. The document then explains how bacterial concrete works to self-repair cracks, highlights advantages like improved strength and durability, and concludes by discussing applications in construction.

1. Bacterial Concrete- A Self Repairing
Biomaterial
PRESENTATION
BY
ABHISHEK KUMAR
CIVIL ENGINEERNG (IIIrd Year)
G.B.PANT ENGINEERING COLLEGE
PAURI

2. INRODUCTION
 Cracking of Concrete is an inevitable
phenomenon.
 Remediation of already existing cracks
has been the subject of research from
many years.
 The various products such as structural
epoxy resins, other synthetic mixtures
are used as a filling agents for repairing
concrete.
 The use of Epoxy resins is neither Eco-
friendly nor safe for human health.

4. It uses a process by which living organisms
form inorganic solids i.e. also called bio-
mineralization.
“The process can occur inside or
outside the microbial cell or even
some distance away within the
concrete. Often bacterial activities
simply trigger a change in solution
chemistry that leads to over saturation
and mineral precipitation. Use of these
Bio mineralogy concepts in concrete
leads to potential invention of
new material called ―Bacterial
Concrete”

6. Bacterial Classification :-
In this study the four different kinds of
bacteria were used and comparison
results are based on them, these are
classified as:-
 B. Pasturii
 B. Subtiles
 B. Sphaericus
 B. Cohnii

7. Activation Mechanism
(B.Pasturii)
B . Pasturii is activated by the
mechanism of oxidative determination
of amino acids and the nutrients
required for its formation are:-
 Trypticase
 Yeast extract
 Tricine
 Agar solution
 Glutamic Acid

8. Activation Mechanism
(B.Subtiles)
B . Subtiles is activated by the
mechanism of Hydrolysis of Urea and
the nutrients required for its formation
are:-
 Urea
 Calcium salts
 Ammonium chloride
 Sodium Bicarbonate

9. Activation Mechanism (B.
Sphaericus)
B . Sphaericus is activated by the
mechanism of bio oxidative analysis of
Urea and the nutrients required for its
formation are:-
 Urea
 Yeast Extract
 Calcium Salts

10. Activation Mechanism (B. Cohnii)
B . Cohnii is activated by the
mechanism of bio oxidative analysis of
Urea and the nutrients required for its
formation are:-
 Peptone
 Yeast extract
 Actical
 Natamycine

11. HOW DOES BIO CONCRETE
WORKS.....
 when a concrete structure is damaged and water starts to seep
through the cracks that appear in the concrete, the spores of
the bacteria germinate on contact with the water and Calcium
lactate.
 Having been activated, the bacteria start to feed on the calcium
lactate. 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.

12. It mimics the process by which bone
fractures in the human body are naturally
healed by osteoblast cells that mineralise to
re-form the bone.
The consumption of oxygen during the
bacterial conversion of calcium lactate to
limestone has an additional advantage.
Oxygen is an essential element in the
process of corrosion of steel and when the
bacterial activity has consumed it all it
increases the durability of steel reinforced
concrete constructions.

13. Why bacteria activates only after
crack
 The two self-healing agent parts (the
bacterial spores and the calcium
lactate-based nutrients) are
introduced to the concrete within
separate expanded clay pellets 2-4
mm wide, which ensure that the
agents will not be activated during the
cement-mixing process. Only when
cracks open up the pellets and
incoming water brings the calcium
lactate into contact with the bacteria
do these become activated.

14. Process of fixing cracks in concrete by
bacteria

16. SCANNING ELECTRON MICROSCOPY INVESTIGATIONSCANNING ELECTRON MICROSCOPY INVESTIGATION
 To give a visual documentation of the extent of mineral
precipitation in various regions within the cement mortar.
 To characterize the microstructure relationship of the
precipitates and the filling material.
 To confirm the elemental composition of the mineral
precipitates.
 To identify microscopic evidence supporting the
participation of bacteria in mineral precipitation.

17. Microstructure Examinations:-
 It is based on the micrograph obtained
by scanning electron microscopic
analysis.
 From the micrograph it was
investigated the growth of rod shaped
fabulous deposition in concrete with
bacteria.
 It also reveals the calcifying power of
the different bacterial micro-organisms
and their interaction with concrete.

18. Magnified image of full-grown calcite crystals with distinct and
sharp edges, found in the interior surface of the crack.
Magnified image of full-grown calcite crystals with distinct and
sharp edges, found in the interior surface of the crack.

19. Rod Shaped Deposition on
Concrete Surface
Rod-shaped impressions, consistent with the dimensions of B. pasteurii
are spread around the calcite crystals, formed on the surface of the
specimens subjected to sulfate attack.
Rod Shaped
Impressions
Rod-shaped impressions, consistent with the dimensions of B. pasteurii
are spread around the calcite crystals, formed on the surface of the
specimens subjected to sulfate attack.
Rod Shaped
Impressions

20. Developing Calcite Crystals

21. Magnified Image of Calcite
Crystals
agnified image of calcite crystals developed on the surface of th
ement mortar beams with bacteria subjected to alkali aggregate
agnified image of calcite crystals developed on the surface of th
ement mortar beams with bacteria subjected to alkali aggregate

22. Advantages:-
 It remediates cracks quickly.
 It improves the compressive strength
of the concrete.
 It increases the durability of concrete.
 Reduction in corrosion of
Reinforcement.
 Asthetic appearance are not harmed
through this.
 It is pollution free and natural.

23. Durability Comparison
Comparison of change in durability factor for specimens made with and
without bacteria and subjected to freeze thaw cycles
100 100 100 100
86.11 87.52
91.81 92.05
0
20
40
60
80
100
Control1 Control2 Bacteria1 Bacteria2
Mix Designation
DurabilityFactor.
0 cycles
300 cycles

24. Compressive Strength
Comparision
Bacteria Specimen
Compressive
Strength for M25
B. Pasturii 30
B. Subtiles 33
B. Sphaericus 28
B. Cohnii 29

25. Disadvantages
 It is somewhat costlier than
conventional concrete.
 Investigation of calcite precipitation is
very costly.

26. APPLICATION OF BACTERIA IN
CONSTRUCTION AREA
 This new technology can provide
ways for low cost and durable roads.
 High strength buildings with more
bearing capacity.
 Long lasting river bank.
 Erosion prevention of loose sands
 Low cost durable housing.

27. Green Roofing
 -Roof covered with vegetation cover over a water
proofing materials.
 -A layer of mosses are allowed to grow due to the
nutrient media provided by biological concrete.
 Practised generally for several purposes-:
 Absorbing rainwater thus keeping house cool and
also surronding.
 Reduces pollution and providing hygienic
environment.

29. CONCLUSIONS:-
•Microbial 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.
•Work of various researchers has improved our
understanding on the possibilities and limitations
of biotechnological applications on building
materials.
•Enhancement of compressive strength, reduction
in permeability, water absorption, reinforced