1. Under the guidance of,
Dr. P.C SABUMON
PRESENTED BY,
BALAJI..N
(13MST1028)
2. Cracks in concrete are inevitable and are one of the inherent
weaknesses of concrete. Water and other salts seep through
these cracks, corrosion initiates, and thus reduces the life of
concrete.
Remediation of already existing cracks has been the subject of
research for many years.
The various products such as structural epoxy, resins, epoxy
mortar and other synthetic mixtures are used as a filling agents
for repairing concrete, but these are neither environment
friendly nor safe.
3. The materials that are capable of controllable response to
the environment are called smart materials.
A dumb material can be made smart by combining them
with microorganisms.
In the study microorganism added are, Bacillus pasteurii,
common soil bacteria. Since the cracks are remediated by
the microorganisms the process is called the
microbiologically-enhanced crack remediation (MECR)
process.
4. To repair minor/micro cracks of concrete by bacterial action.
Cast specimen and test for load to crack and treat with bacterial
biomass and study the repairing action.
5. SL NO NAME OF AUTHOR YEAR RESEARCH WORK
1)
2)
3)
4)
Ramakrishnan et al
Barabesi et al
Day J L et al
Muynck et al
2001
2007
2003
2008
microbiologically induced calcite (CaCO3)
precipitation. (MICP) is reported by the
research group
he has studied calcite formation by
Bacillus subtilis, in order to identify genes
involved in the biomineralization process.
This paper describes the results of an
innovative approach in concrete crack
remediation utilizing microbiologically
induced calcite .
Shortcomings of conventional surface
treatments have drawn the attention to
alternative techniques for the
improvement of the durability of concrete.
6. SL NO NAME OF AUTHOR YEAR RESEARCH WORK
1)
2)
3)
4)
Leuschner et al
Marvasi et al
Patil et al
Nagaraj et al
2001
2009
2008
2004
Research was conducted to examine the
effects of dehydration and rehydration on
radioactive phosphorous and carbon
molecular mobility in dormant Bacillus
subtilis spores.
They have chosen Bacillus subtilis 168 as
their model to study which physiological
aspects are associated with calcium
carbonate (calcite) formation during
biofilm development when grown on
precipitation medium.
Efficiency of Microbiologically Enhanced
Crack Remediation was evaluated by
comparing the compressive strength
check in involvement. of Bacillus pasteurii
in calcite precipitation.
He says that for proportioning concrete
mixes water cement ratio becomes a
dominant factor, when the strength of
concrete is lesser than that of aggregate
7. • Bacterial concrete is a self-remediating biomaterial, in
which microorganisms, Bacillus pasteruii, a common soil
bacterium, are added which can continuously precipitate
calcite, which fills the cracks.
• The phenomenon of calcite precipitation is called
Microbiologically Induced Calcium Carbonate
Precipitation (MICCP).
• Actually bacterial concrete is not a concrete. Bacteria are
just introduced either on the hardened concrete or into the
concrete before placing.
9. METHODOLOGY
Review of literature
Study of bacterial concrete
Comparison of crack before and after
injecting bacteria using NDT
Application of load induce
hair pin crack find crack
width using NDT
Preparing the reinforced
concrete beams
Bacterial injection to beam in
medium and curing
Result
10. MATERIALS AND METHODS
Ordinary Portland cement of 53 Grade.
Size of beam available in our lab 100*100*500.
BACTERIAL SOURCES
Microorganisms Bacillus pasteurii and Bacillus sphaericus
were obtained pure bacterial culture was isolated named as
isolate 1 from curing tank at Civil Engineering PG Research
lab, M S Ramaiah Institute of Technology Bangalore.
11. Using the compression testing machine, care should be taken
for inducing very minor crack like hair pin crack.
Crack width has to be determined using NDT.
Medium of Bacterial Concrete
•Three different mediums were selected for test.
•Water
•Phosphate-buffer solution
•Urea-CaCl2
12. The beam specimens after de-molding are immersed in
triplicates in respective bacterial solution grown overnight
separately for 24hrs. After 24hrs the beam are wiped with
a blotting paper to remove any surface bacteria and cured
in corresponding calcite precipitation media (Calcium
source 49gm/Lt + Urea 20g/Lt) at room temperature
(Figure) until compression testing at the intervals of 7, 14
and 28 days. Media were replaced at a regular interval of 7
days. Control samples need to be prepared in similar
manner and cured in water. Compression testing is
performed in compression testing machine.
13. Dr .sookie bang in 2007
Dr.v. ramakrishnan in 2007
