This document presents information on bioconcrete or self-healing concrete. Bioconcrete contains bacteria and a chemical precursor that allows cracks in concrete to autonomously heal. The bacteria used are from the Bacillus genus and are able to withstand the alkaline environment of concrete. Calcium lactate acts as the chemical precursor that activates the bacteria, causing them to precipitate calcium carbonate to fill cracks. While bioconcrete shows promise for self-healing abilities, further optimization is needed to avoid compromising the concrete's strength and ensure the bacteria remain viable for longer periods of time to continuously heal cracks as they form.

1. PRESENTED BY-
SOUMALYA BAG
ROLL NO-20125005
PAPER CODE-CE(892)
UNDER THE GUIDANCE OF
Mrs. APARNA ROY & Mr. SOUMEN ROY
SEMINAR REPORT ON

2. INTRODUCTION
Crack formation is a typical phenomenon
related to durability.
Percolation of cracks 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 consists of bacteria and an organic mineral precursor
compound.

3. WHAT IS BIO CONCRETE
Its is a special type of concrete invented by a group of
microbiology researchers under the head of Henk Jonkers.
Bio concrete is also called as BACTERIAL CONCRETE or
self healing concrete.
Its specially made to increase
the lifespan or the durability
of concrete structure by
the self healing action
of that concrete.

4. WHAT SPECIAL PRESENT IN BIO CONCRETE
There are two thing present in bio 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.

5. WHAT BACTERIA IS USED
Most of the bacteria belongs to genus bacillus are fulfilling the required
criteria discussed above. some of the list of bacteria are
B. Pseudofirmus ,
B. Cohnii B. Filla B. Pasteurii…etc
The suitable chemical precursor found to be most suitable is
“calcium lactate” Ca(C3H5O2)2

6. CLASSIFICATION OF BACTERIAS
Bacteria is generally classified in three category
Basis on Shape, Basis on Gram Stain and Basis on
Oxygen Demand which shown in Fig. 2 and sub
types of each category also can be shown in Fig. 3,
Fig. 4, and Fig. 5.

7. Fig.3 Classification on Basis of shape

8. Fig.4 Classification on Basis of Gram Stain

9. Fig. 5 Classification on Basis of oxygen demand

10. WHAT IS HAPPENING INSIDE BIO
CONCRETE(MECHANISM)
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 crack and the precursor is activated

11. Ca(C3H5O2)2 + 7O2 → CaCO3 + 5CO2 + 5H2O
CO2 + Ca(OH)2 → CaCO3 + H2O
(carbonation)
The activated precursor intern induces the bacteria to react with
that precursor and form a base of calcium carbonate called as
limestone, the chemical equation is given above

12. HOW THE HEALING AGENTS ARE APPLIED
1) BY DIRECT APPLICATION
The bacteria and the chemical precursor(calcium lactate) are
added directly while making the concrete.
2) ENCAPSULATION LWA
a) The part of the coarse aggregate is replaced by the light
weight aggregate(LWA) , which is impregnated with twice the
calcium lactate solution and the spores of bacteria.
b) After impregnation the clay particles with 6% healing agents
and the concrete is made .

15. BEFORE HEALING AFTER HEALING

16. 20x

17. 40x

20. The Concrete properties should not be negatively
affected by addition of a healing agent to the concrete
mixture.
a large amount of bacteria and certain mineral precursor
compounds like calcium lactate do substantially
influence concrete compressive and tensile strength
when the healing agent is added, Optimization of
healing agent is necessary so that it wont affect the
characteristics of concrete
EVALUATION

21. CONCLUSION
The spores would be crushed by smaller holes.
No strong spores were detected in a 135-day old
specimen, implying the majority of spores in the cured
cement mixture were available for less than 4 months.
Further research is needed to increase the time period
that the bacterial spores remain in the concrete. It could
be possible.