Self-healing concrete contains special bacteria and a chemical precursor that allow it to autonomously repair cracks. When cracks form, water activates the precursor which induces bacteria to fill the cracks with limestone, healing them. This increases the concrete's durability and service life. The bacteria, like Pseudofirmus and Cohnii, must withstand the alkaline environment. Calcium lactate is a commonly used precursor that the bacteria metabolize to precipitate limestone. This technology could enable more durable infrastructure with reduced maintenance needs.

1. PRESENTED BY
CHIRAG BHANDARI AB16002
RAMSHARAN KELLA AB16006
INDERBIR SINGH AB16010
JATIN SEHGAL AB16021
SAURABH PRADHAN AB16015
SAKET AGRAWAL AB16021

3.  Crack formation is a typical phenomenon related to
durability.
 Percolation of crack may lead to leakage problems,
causing deterioration of the concrete matrix or
corrosion of embedded steel reinforcement.
 In recent years a bacteria –based self healing concrete
is being developed in order to extend the service life.
 A two component healing agent is added to the
concrete mixture.
 The agent consist of bacteria and an organic mineral
precursor compound.
INTRODUCTION

4. WHAT IS SELF HEALING CONCRETE
 It is a special type of concrete invented by a group
of microbiology researchers under the head of
henk jonkers.
 Self healing concrete is also know as “BIO
CONCRETE” Or “BACTERIAL CONCRETE”.
 It is specially made to increase the life span of the
durability of concrete structure by self healing
action of that concrete.

5. WHAT SPECIAL PRESENT IN SHC
CONCRETE
 There are two things present in self healing concrete .
1) The special bacteria that has to resist the alkalinity
and the mechanical stress of concrete.
2) The chemical precursor to activate the bacteria.

6. WHAT BACTERIA IS USED
 Most of the bacteria belongs to genus bacillus are
fullfilling required criteria discussed 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. WHAT IS HAPPENING INSIDE SHC
CONCRETE
 The cracks are formed on the surface of concrete
due to many reasons like shrinkage, inadequate
water for hydration…etc.
 The water is deliberately forced into the cracks and
the precursor is activated.
 The activated precursor intrim induces the
bacteria to react with the precursor and form a
base of calcium carbonate called as limestone and
the crack is filled up.

8. HOW THE HEALING AGENTS ARE
APPLIED
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.

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

11. 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 labour is required.

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

13. 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.