2. Concrete is the most widely used material for
construction.
It has low tensile strength than compressive strength.
So is most effective when reinforced by steel bars.
Concrete is a brittle material with low tolerance for
strain.
3. So it forms cracks, leading to
corrosion
water ingress
Decrease in durability
increasing maintenance cost
self healing concrete is a solution to all above.
Here we will induce self healing property using JC3
(Bacillus subtilis) bacteria.
4. JC3 is a gram +ve
bacteria
Can be cultivated
easily in lab with
minimum cost
It is non-
pathogenic
Bacillus
subtilis(JC3)
6. Analysis of compressive strength with varying
bacterial con.
Analysis of split tensile strength .
Effect of bacterial conc. on different grades of concrete
7. JC3 bacteria is added to concrete with Calcium lactate
as feeding material.
The conc. of JC3 bacteria is proportional to H2O conc.
Calcium lactate & JC3 mixture is added in form of
palates .
Initially JC3 bacteria spores remain in dormant state
These spores germinate when come in contact with
H2O in temp around 25deg.
8. When cracks are formed ,the local palates also breaks
releasing JC3
Water also seeps through cracks
Bacterial spores germinates when comes in contact
with H2O
JC3 feeds on Calcium lactate forming CaCO3 which
precipitates on cracks.
This process is known as Microbiologically Induced
Calcium Carbonate precipitation(MICCP)
9. MICCP involves a complicated chain of reaction.
But can sum up to following two steps
Ca2+ + Cell → Cell-Ca2+
Cell-Ca2+ + CO32- → Cell-CaCO3↓
14. No of days Controlled
concrete
(Mpa)
Bacterial
concrete
(Mpa)
%increase
7 3.78 4.30 13.75
14 4.62 5.28 14.28
28 4.85 5.74 18.35
15. The use of Self healing concrete has been very
limited world wide .
The concept is still in developing stage & on the way to
large scale use.
In India no use of this has been done.
A group of professors in JNTU are researching on
bacterial concrete.
16. Based on the present experimental investigations, the
following conclusions are drawn:
decrease of permeability of water and other liquids in
concrete.
increases the compressive strength of concrete. The
compressive strength
Splitting tensile strength is increased
All over maintenance cost is minimized
17. From all above results we can consider non pathogenic
bacteria as a major material for inducing self healing
property in concrete.
Now self healing concrete can be said to be future
material.
18. Wang, J., Van Tittelboom, K., De Belie N., and Verstraete,
W.. "Use of Silica Gel or Polyurethane
Immobilized Bacteria for Self-healing Concrete."
Construction and Building Materials 26.1 (2012): 532-
40.Print.
Li, V., University of Michigan, “Self-healing concrete for
safer, more durable infrastructure.” Science Daily,22 Apr.
2009. Web. 28 Feb. 2012.
Jonkers, H. M., A. Thijssen, G. Muyzer, O. Copuroglu, and
Schlangen, E. "Application of Bacteria as Selfhealing Agent
for the Development of Sustainable Concrete." Elsevier.
Elsevier B.V., 30 Dec. 2008. Web. 25Feb. 2012.
19. Brownell, Blaine. "Self-Healing Concrete." Architect, The
AIA Magazine (2011): 90-91. Print. O'Driscoll, Cath.
"Bacteria Fill in the Gaps in Concrete." Chemistry &
Industry (2010). Web. 11 Feb. 2012.
Zwaag, S. Van Der, and Schmets A. J. Self Healing
Materials: An Alternative Approach to 20 Centuries of
Materials Science. Dordrecht, The Netherlands: Springer,
2007. Print.
Yonkers, H. M., and E. Schlangen. "Crack Repair by
Concrete-immobilized Bacteria." Proc. of First
International Conference on Self Healing Materials, Delft
University of Technology, Noordwijk Aan Zee. Springer,
2007. Print
