A special type of concrete which provided with specific bacteria to fill the cracks in the concrete by converting the unreacted silica(cement) to limestone.

1. PRESENTATION
ON
“SELF HEALING CONCRETE”
PRESENTED BY :
IRSHAD ANSARI

2. CONTENT
1. Introduction
2. Necessity
3. Bacteria
4. Working on self healing concrete
5. Methods
6. Advantages
7. Disadvantages
8. Applications
9. Conclusion

4. 1. INTRODUCTION
DEFINITION-
Self healing concrete is a
concrete which heals itself when it comes
in contact with air and water, it produces
lime on outer layer of concrete.
 In most of the traditional concrete
mixtures 20-30% of the cement is left
unhydrated.
 If cracking of the concrete occurs,
unreacted cement grains may become
exposed to moisture penetrating the
cracks.
 In that case the hydration process may
start again and hydration products may
fill up and heal the crack.

5. NECESSSITY

6. BACTERIA
 Most of the bacteria belongs to genus bacillus are fulfilling required criteria
discusseed above. Some of the list of bacteria are-
1) Pseudofirmus
2) Cohnii
3) Filla
4) Pasteurii
 The suitable chemical precursor found to be most suitable is “CALCIUM
LACTATE”.

7. Negatively charged cell wall and the
presence of positive charged ions
Biomineral production by
means of bind
Bacteria
structure

8. WORKING ON SELF HEALING CONCRETE
 Self healing concrete is a product that will biologically produce lime stone
to heal cracks that appear on the surface of concrete structures.
Ca(C3H5O2)2 + 7O2 CaCO3 + 5CO2 + 5H2O
(calcium lactate) (lime)
 Specially selected types of the bacteria genus bacillus along with a calcium–
based nutrients known as calcium lactate, and nitrogen and phosphorus, are
added to the ingredients of the concrete when it is being mixed.

9. Crack exposes bacteria
Bacteria multiply when water fills crack
Bacteria produce healing products

10. METHODS
1) BY DIRECT APPLICATION
The bacteria and the chemical precursor are added directly while making
the concrete
2) ENCAPSULATION LWA
• The part of the coarse aggregate is replaced by the light weight
aggregate, which is impregnated with the twice the calcium lactate
solution and the spores of bacteria
• After impregnation the clay particles with 6% healing agents and the
concrete is made

11. ADVANTAGES
 Helps to fill the cracks
 Improvement in compressive strength of concrete
 Better resistance towards freeze thaw attack reduction
 Reduction in permeability of concrete
 Reduction in corrosion of reinforced concrete
 Helps to reduce maintenance and repair

13. DISADVANTAGES
 Cost of self healing concrete is double than conventional concrete
 Growth of any bacteria is not good in any atmosphere media
 There is no IS code or other code is available
 Investigation of calcite precipitation is costly studied
 Skilled labor is required

14. APPLICATIONS
 Self healing concrete can be used for sectors such as tunnel-lining, structural
basement walls, highways, bridges, concrete floors and marine structures
 This new technology can provide ways to durable roads
 High strength buildings with more earing capacity
 Long lasting river banks
 Erosion prevention of loose sands

15. CONCLUSION
 Microbial concrete technology has proved to be the better than many
conventional technologies because of its ecofriendly nature and self healing
abilities and increase in durability of various building materials and give
them high strength for more bearing capacity and increase the life of the
building
 Hence, self healing concrete is crack resistant
 Which protects the concrete and reinforcement from cracks and from
corrosion
 By doing this, it prevents water to percolate into reinforced steel concrete
and hence it does not comes in contact with reinforcements
 Thus, it prevents reinforcement from corrosion

16. THANK YOU