BIO-CONCRETE

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SELF HEALING CONCRETE

• BIO-CONCRETE
• Prabhat kumar sahu
• 0901109200
• Civil engg

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INTRODUCTION

• 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.

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• 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.

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Bacillus subtilis(JC3)

• JC3 is a gram ve bacteria
• Can be cultivated easily in lab with minimum cost
• It is non-pathogenic

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EXPERIMENTAL PROGRAMME

• Objectives
• Experimental procedure
• Chemical reactions
• Experimental results

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OBJECTIVE

• Analysis of compressive strength with varying
  bacterial con.
• Analysis of split tensile strength .
• Effect of bacterial conc. on different grades of
  concrete

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Procedure

• 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.

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• 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)

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Chemical process

• MICCP involves a complicated chain of reaction.
• But can sum up to following two steps
• Ca2 Cell ? Cell-Ca2
• Cell-Ca2 CO32- ? Cell-CaCO3?

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Surface 1 Concrete surfaceSurface 2
CaCO3 ptt
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PLAIN CONCRETE
BACTERIAL CONCRETE
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Experimental results
Cell Conc./ml of water Compressive strength (28 days)(Mpa) increase
NIL 51.81 _
104 58.02 11.99
105 61.79 16.15
106 57.21 10.42
107 54.66 5.51
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Compressive strength (28 days)
Grade of concrete Controlled concrete (Mpa) Bacterial concrete (Mpa) increase
M 20 28.18 32.74 16.18
M 40 51.19 60.17 17.54
M 60 72.61 94.21 29.75
M 80 93.8 119.2 27.08
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Spliting tensile strength
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
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Prctical use

• 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.

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CONCLUSION

• 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

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• 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.

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Referrence

• 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.

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• 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

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