abstract for self healing

7/21/2019 ABSTRACT for Self Healing

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Classifcation on Basis o shape

SELF-HEALING MATERIAL BACTERIAL CONCRETE

M.Sivakumar S.Kumaresan

Adhiarasak!hi En"ineerin" C#$$e"e

Me$maruva!hur.

ABSTRACT-- Micro-cracks are the main causeto structural failure. One way to circumvent costly

manual maintenance and repair is to incorporate

an autonomous self -healing mechanism in

concrete. One such an alternative repair

mechanism is currently being studied, i.e. a novel

technique based on the application of

biomineralization of bacteria in concrete. The

applicability of specifically calcite mineral

precipitating bacteria for concrete repair and

plugging of pores and cracks in concrete has beenrecently investigated and studies on the possibility

of using specific bacteria as a sustainable and

concrete -embedded self-healing agent was studied

and results from ongoing studies are discussed.

ynthetic polymers such as epo!y treatment etc. are

currently being used for repair of concrete are

harmful to the environment, hence the use of a

biological repair technique in concrete is focused.

"ecently, it is found that microbial mineral

precipitation resulting from metabolic activities of

favourable microorganisms in concrete improved

the overall behaviour of concrete. #ence in thispaper define the bacterial concrete, its classification

and types of bacteria, chemical process to fi! the

crack by bacteria, advantages and dis-advantages

and possibilities of application of M$%&

'Microorganism used for %alcium %arbonate

&recipitation in %oncrete( in construction area by

literature review are discussed

INTRO%&CTION

Concrete which forms major component in the

construction Industry as it is cheap, easily availableand convenient to cast. But drawback of these

materials is it is weak in tension so, it cracks under

sustained loading and due to aggressive

environmental agents which ultimately reduce the

life of the structure which are built using these

materials. This process of damage occurs in the early

life of the building structure and also during its life

time. Synthetic materials like epoies are used for

remediation. But, they are not compatible, costly,

reduce aesthetic appearance and need constant

maintenance. Therefore bacterial induced Calcium

Carbonate !Calcite" precipitation has been proposed

as an alternative and environment friendly crack

remediation and hence improvement of strength of

building materials.

CLASSIFICATION OF BACTERIA

Bacteria is generally classified in three categoryBasis on Shape, Basis on #ram Stain and Basis on

$ygen %emand which shown in 'i"and sub types

of each category also can be shown in 'i".


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Carbonate Precipitation in Concrete

&Type here'

(ARIO&S T)*ES OF BACTERIA &SE% IN

CONCRETE

There are various types of bacteria were used inconstruction area, from literature review it is as shown in

and other application of bacteria are shown in Ta+$e.,

andTa+$e

Ta+$e-

, Overvie #' vari#us C#ns!ru/!i#n

Ma!eria$s made usin" MIC*

Ta+$e- Mi/r##r"anism used '#r Ca$/ium

HO0 %OES BIO-CONCRETE 0ORK1

Self(healing concrete is a product that will biologically

produce limestone to heal cracks that appear on thesurface of concrete structures. Specially selected types of

the bacteria genusBacillus

, along with a calcium(basednutrient known as calcium lactate, and nitrogen and

phosphorus, are added to the ingredients of the concretewhen it is being mied. These selfhealing agents can lie

dormant within the concrete for up to )** years.

*ROCE%&RE

*reara!i#n #' Ba/!eria$ S#$u!i#n

+rimarily ).-g of utrient broth !media" is added to a

-**ml conical flask containing distilled water. It is thencovered with a thick cotton plug and is made air tight

with paper and rubber band. It is then sterili/ed using a

cooker for about *()* minutes. ow the solution is free

from any contaminants and the solution is clear orange in

colour before the addition of the bacteria &-'.


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&Type here'

Fi" -,2Solution without bacteria !only media"

0ater the flasks are opened up and an eactly ml of the

bacterium is added to the sterili/ed flask and is kept in a

shaker at a speed of -*()** rpm overnight. 1fter )2

hours the bacterial solution was found to be whitish

yellow turbid solution.

Fi" -2Solution with bacteria

C#mressi#n S!ren"!h Tes!

The cubical 3oulds of si/e -*mm -*mm -*mm

were cleaned and checked against the joint movement. 1

coat of oil was applied on the inner surface of the

3oulds and kept ready for the concreting operation.

3eanwhile the re4uired 4uantities if cement, fine

aggregate and coarse aggregate !passing through IS sieve

of )* mm si/e and retained on 2.5- mm" for the

particular mi are weighed accurately for concreting.

6ine aggregate and cement were mied thoroughly in a

hand mier such that the colour of the miture is

uniform. Then, weighed 4uantity of coarse aggregate is

added to the mier and then it rotated till uniform dry

miture is obtained. Then, calculated 4uantity ofbacterial solution and water was added and miing was

continued for about 7 to - minutes to get a uniform mi.

The wet concrete is now poured into the 3oulds and for

every ) to 7 layers and compacted manually. 1fter

concreting operations, the upper surface is leveled and

finished with a mason s trowel. The corresponding

identification marks were labeled over the finished

surface and they were tested for 5 and )8 day strengths

in a compressive strength testing machine &2'.

Fi" -32Concrete cube subjected to compression

,., F$e4ura$ S!ren"!h Tes!

3oulds of *cm *cm -*cm is used and the 3oulds

are cleaned and the joints between the sections of


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&Type here'

3oulds shall be thinly coated with 3oulds oil and a

similar coating of 3oulds oil shall be applied between

the contact surfaces of the bottom of the 3oulds and the

base plate in order to ensure that no water escapes during

the filling. The interior faces of the assembled 3oulds

shall be thinly coated with 3oulds oil to preventadhesion of the concrete. 3eanwhile the re4uired

4uantities of cement, fine aggregate and corresponding

coarse aggregate for the particular mi are weighed

accurately for concreting. 6ine aggregate and cement

were mied thoroughly in a hand mier such that the

colour of the miture is uniform. Then, weighed 4uantity

of coarse aggregate is added to the mier and then it

rotated till uniform dry miture is obtained. Then,

calculated 4uantity of water and bacterial solution was

added and miing was continued for about 7 to - minutes

to get a uniform mi. The wet concrete is now poured

into the 3oulds in ) to 7 layers and compacted manually.1fter concreting operations, the upper surface is leveled

and finished with a mason s trowel. The corresponding

identification marks were labeled over the finished

surface and the beams were tested for 5 and )8 days

strengths.

. RES&LTS AN% ANAL)SIS

The test results showed a significant difference in the

specimens tested, with and without bacteria. 9ere are the

following tables and charts which will give clearinformation about the compression and fleural strength

test results.

Ta+$e -,2compressive strength test results for 5 and )8

days

SI.$ %ays

ormal

concrete

!:mm)"

Bacterial

concrete

!:mm)"

5 )*.82 )5.*;

) )8 );.;; 78.;8

Ta+$e -2fleural strength test results for 5 and )8 days

SI.$ %ays

ormal

concrete

!:mm)"

Bacterial

concrete

!:mm)"

5 7.;) 2.

abstract for self healing

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