CORROSION BASED DURABILITY STUDY IN … constant voltage technique method of corrosion testing is adapted. Specimen size of 100mmx100mmx100mm were cast and steel rod of 150mm was used

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International Journal of Civil Engineering and Technology (IJCIET) Volume 8, Issue 9, September 2017, pp. 680–691, Article ID: IJCIET_08_09_077

Available online at http://http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=8&IType=9

ISSN Print: 0976-6308 and ISSN Online: 0976-6316

© IAEME Publication Scopus Indexed

CORROSION BASED DURABILITY STUDY IN

CONCRETE USING BIOMINERALIZATION

R. Vasanthi

Associate Professor, Department of Civil Engineering,

Vetri Vinayaha College of Engineering and Technology, Thottiyam, Tamil Nadu, India

Dr. R. Baskar

Associate Professor, Department of Civil & Structural Engineering, Annamalai University,

Annamalai Nagar, Chidambaram, TamilNadu, India

ABSTRACT

The resistance of concrete against attacks by acid, weather, abrasion, corrosion is

named as durability, which will also influence engineering properties. Degree of

durability and engineering property depends on the major factor of micro pores and

their bonding in interconnection. Pre casting factors such as its ingredients, mix

proportions, placing and curing methods, the surrounding environmental conditions

also being the next dependable factor for properties of concrete. All this factors serves

as the element of life span of concrete structure. These factors are inversely

proportional to life span of structures, as it increases the life of the structure gets

decreased. Sealing micro pores will not only increase its engineering properties but

also increase the durability factor such as corrosion, permeability etc., In this a clear

study has been made on Corrosion which holds a greater part in deterioration of

structures, corrosion starts due to the formation of cracks in the structure, sealing of

cracks may be a possible at its exterior levels, but in its internal structure cracks

grows consecutively, a bio approach has been applied in sealing the micro pores and

cracks internally in the structure by bacterial growth, which precipitates calcite which

seal the micro pores and cracks thereby increasing engineering and durability factors.

Hence biomineralization using Bacteria is a sustainable and an eco-friendly output

towards the existing needs against strength and serviceability of structure.

Keywords: Lactobacillus spp, Saccromyces spp and Rhodopseudomonas spp, Bacillus

Subtilis, Load Test, Accelerated Corrosion Test.

Cite this Article: R. Vasanthi and Dr. R. Baskar, Corrosion Based Durability Study in

Concrete Using Biomineralization, International Journal of Civil Engineering and

Technology, 8(9), 2017, pp. 680–691.

http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=8&IType=9

R. Vasanthi and Dr. R. Baskar


1. INTRODUCTION

Concrete is a keen material in construction. Maintenance of concrete is one of the major

issues in concrete structures. Renovation can be done to a maximum case of externally,

building a smart renovation from its inner part is always been a greater risk for the engineers

and designers. When the surface gets any cracks or fissures due to drying shrinkage there will

be more pores on the surface of concrete. Through this aggressive gases, chemicals like,

oxygen, carbon-di-oxide, water, chloride, sulphate etc, will penetrate, resulting in reduction

on strength and durability of the structure. The penetration of ingress ion through pores of the

concrete the reinforcement steel gets corroded. In order to prevent such kinds of problem bio-

mineralization is a technique which was arrived. The bacteria, precipitating calcium carbonate

which act like lime stone ,if any aggressive agencies enter through pores the bacteria

immediately get activated and precipitate calcite which will arrest these cracks, due to the

penetration of chloride ion and sulphate inside the concrete there will be a decremental effect

on durability this lead to corrode the reinforcement steel in the concrete [1].The concrete

structure has more pore which is the way for the material degradation, the penetrating

aggressive agent inside the surface causes more impact on mechanical properties of the

concrete which is an important factor for durability of the concrete[2].The calcite precipitation

improves the overall performance on both mechanical and durability. Different types of

bacteria will produce different calcite precipitation in different environment in a different way

[3].Specified bacterial species precipitates calcite in a highly impermeable and resistance to

corrosion. This microbial concrete increases the life of the structures. Microbial activities will

be eco-friendly and it is natural. The process of microbial urease hydrolyzes urea to produces

ammonia and carbon- di-oxide, ammonia released to the surrounding subsequently increase

the PH

value, leading to accumulation of calcium carbonate [4].Bacillus sphaericus are pore

forming bacteria which withstand extreme temperature for several years. It gives more

durability and resist corrosion in the concrete. The bacillus flexus have best potential in

producing calcite[5].Externally applied such specific species ureolytic and process occur

inside or outside the concrete surface, microbial cell precipitate bio-mineral such as calcite

which is dense in nature and seal the crack, which will prevent the entry of aggressive gases

and liquids. The bacteria consumes oxygen which will prevent corrosion of reinforcement

steel present in the concrete .Oxygen play an important role in the process of corrosion and

durability of concrete[6].The bacteria acts as a barrier against oxygen to penetrate through the

cracks and it protect the reinforcement steel from corrosion[7].When the concrete subject to

tension the cracks will be caused over the surface .The water seepage through the crack

promotes corrosion in RCC structure and it reduces the life duration of the structure. Self-

healing is the only solution for durability of concrete [8].In wet environmental conditions the

bacterial concrete is very effective and corrosion of reinforcement comes under control. Pores

on the concrete surface partially filled with the growth of bacterial calcite material and reduce

the penetration, also increase the density and strength of the concrete specimen [9]. More

liberation of heat due to hydration of cement causes pores in concrete structure. If more

porosity permits the aggressive gases to penetrate inside and it reduces the life span of the

structure (16).When the penetration of chloride ion reduced the PH value of the concrete,

results in reduction in passivating coat of reinforcement, due to this steel starts corroding. To

prevent such process the calcite precipitation acts as passivate over the steel surface.

Microbiological treatment in concrete improves durability, mechanical properties, and reduces

the corrosion in concrete structure.

Corrosion Based Durability Study in Concrete Using Biomineralization


2. MATERIALS AND METHODS

2.1. CEMENT

Ordinary Portland cement was used for the present study which was examined for all its

characteristics under the procedure followed form IS: 4031-1988 and conforms the codes.

2.2. FINE AGGREGATE

The sand confirming to IS: 383-1970 was used for the study, the river sand was collected

from the nearby sand dig up and verified against its organic and inorganic impurities and also

found that it confirms IS: 2386-1963.

2.3. COARSE AGGREGATE

Size of 20mm was used for the investigation which confirms IS: .383-1970 and its individual

characteristics such as bulk modulus, fineness was calculated in accordance with IS: 2386-

1963. (Methods of test for aggregates for concrete)

2.4. WATER

Ordinary potable water was used for casting the specimens also in curing which confirms IS:

3025-1964[Part 22&23] with IS: 456-2000

2.5. BACTERIA

The microorganism preferred in present study was Bacteria which has greater list, following

Bacteria’s were chosen based on the previous studies,

1) Medium contains a combination of Lactobacillus spp, Saccromyces spp and

Rhodopseudomonas spp

2) Medium contains Bacillus Subtilis

Micro life – Bacillus Subtilis or Grass Bacillus is a catalase- positive bacterium, which

survives in soil, gastrointestinal tract of humans, Bacillus Subtilis is rod shaped, tough,

protective endospore which makes the tolerance limit to a maximum in severe environmental

conditions. They are very good in production of enzyme in all biotechnological operations. In

this present study the above mentioned Bacteria’s were used.

2.6. DURABILITY TEST

Cube specimens of 100mmx100mmx100mm were cast with two medium; MCB [Microbial

Concrete containing Bacillus Subtilis] and MCM [Microbial concrete contains mixture –

Lactobacillus spp, saccromyces spp, Rhodopseudomonas spp] which is added in unique

dosage in their application for 40ml. After the required curing period – 28days, the specimens

were removed from curing and cleaned with dry cloth aided with visual inspection. After that

the specimens were immersed in 5% solution of NaCl and 5% solution of H2SO4. The

specimens were tested against it durability at planned intervals. Aside visual inspection was

also done to read the surface texture of the specimens. After the intervals the specimens were

dried out of the acidic solution and tested for its compression.

2.7. WATER ABSORPTION TEST

Specimen of Size 100mmx100mmx100mm were cast and kept in oven for 105°C and allowed

to cool its own. Then the specimens weighed before immersion and it were immersed in water

bath and weighed after the planned intervals – 12hrs, 24hrs, 48hrs and 96hrs, thereby

calculating the percentage of water absorption for each specimen.



2.8. ACCELERATED CORROSION TEST

The constant voltage technique method of corrosion testing is adapted. Specimen size of

100mmx100mmx100mm were cast and steel rod of 150mm was used which was inserted in

specimen to a depth of 50mm in the concrete cube. A constant voltage of 24V was applied in

the rod. At a regular interval of 1hr the potentials were noted. The crack pattern at the

specified period of time were noted and compared. Fig.1. illustrate the accelerated corrosion

test

Figure 1 Accelerated Corrosion Test

2.9. LOAD TEST

Beam Specimen of size 150mmx150mm and length of 1600mm were cast for the design mix

and applied for the stipulated curing period, which is again imposed for accelerated curing test

with bar projection of 50mm on either side and the optimum duration derived from

accelerated corrosion test was applied and released after that and tested against flexure. Two

point load application was conducted to measure the deflection of the specimens, the results

were plotted and compared as per IS: 516-1999. The test continued till the failure of beam,

after testing it was stopped by gradual release of load using the outlet valve. Fig.2.illustrates

the load test on beams

(a) (b)

Figure 2 a) Accelerated Corrosion (AC) on Casted Specimen b) Load Testing after AC

2.10. SEM (Scanning Electronic Microscope)

SEM analysis was conducted on MCB (Microbial Concrete containing Bacillus Subtilis) and

MCM [Microbial concrete contains mixture – Lactobacillus spp, saccromyces spp,

Rhodopseudomonas spp] specimens, its culture and precipitation formation was studied in

detail.



2.11. XRD (X-Ray Diffraction)

The specimens were also applied for XRD studies, which also proved the formation of

Calcium Carbonate precipitation in a higher level.

3. RESULTS AND DISCUSSIONS

Table.1. and Fig.3 and 4 shows the weight loss comparison of specimens immersed in acidic

environment, specimen imposed to acid HCl for specified percentage, it is seen that out of all

the 120 days an average rate of loss is measured and found as; for CC it is 6.25% and MCB it

is 2.06% and in case of MCM it is 0.42%, and when imposed to H2SO4 CC is found to have

8.32% and MCB have 2.56% and MCM proves a lesser average of 1.02%. The resistance

against acidic environment is due to the formation of calcite precipitation in the micro pores

inside the concrete. Higher the formation of Calcite precipitation greater the resistance against

acidic environment.

Table.1.Durability Test Results-Weight Loss Comparison [HCL and H2SO4 Immersion]

Description 0 Day Avg. 30

Days Avg.

45

Days Avg.

60

Days Avg.

90

Days Avg.

120

Days Avg.

Conventional Concrete immersed in HCL Solution

CC1 2.606

2.620

2.600

2.615

2.567

2.560

2.421

2.423

2.368

2.392

2.296

2.296 CC 2 2.644 2.640 2.604 2.465 2.398 2.364

CC 3 2.610 2.606 2.509 2.420 2.410 2.228

Microbial Concrete containing media with LSR [40ml] – immersed in HCL Solution

MCM1 2.491

2.502

2.489

2.500

2.483

2.494

2.478

2.488

2.471

2.482

2.465

2.474 MCM2 2.528 2.524 2.520 2.515 2.509 2.499

MCM3 2.488 2.488 2.478 2.471 2.465 2.457

Microbial Concrete containing Bacillus Subtilis [40ml]- immersed in HCL Solution

MCB1 2.590

2.613

2.587

2.603

2.560

2.584

2.551

2.564

2.540

2.535

2.500

2.510 MCB2 2.610 2.600 2.581 2.570 2.530 2.510

MCB3 2.638 2.623 2.610 2.571 2.536 2.520

Conventional Concrete immersed in H2SO4 Solution

CC1 2.510

2.521

2.480

2.480

2.440

2.447

2.390

2.363

2.150

2.187

2.050

2.080 CC 2 2.560 2.500 2.480 2.400 2.210 2.100

CC 3 2.492 2.460 2.420 2.300 2.200 2.090

Microbial Concrete containing media with LSR [40ml] – immersed in H2SO4 Solution

MCM1 2.535

2.524

2.530

2.497

2.529

2.515

2.526

2.512

2.520

2.493

2.515

2.455 MCM2 2.505 2.500 2.490 2.490 2.460 2.400

MCM3 2.531 2.529 2.527 2.520 2.500 2.450

Microbial Concrete containing Bacillus Subtilis [40ml]- immersed in H2SO4 Solution

MCB1 2.606

2.555

2.600

2.537

2.580

2.530

2.550

2.490

2.500

2.460

2.460

2.430 MCB2 2.545 2.536 2.510 2.490 2.450 2.430

MCB3 2.515 2.512 2.500 2.470 2.430 2.400



Figure 3 Comparison Chart on Weight loss immersed in HCl Solution

Figure 4 Comparison Chart on Weight loss immersed in H2SO4 Solution

Table 2 and fig 5 and fig.6. illustrates the comparison between the compressive loss of

specimens. While analyzing the Compressive strength loss it shows that Conventional

Concrete in HCL and H2SO4 shows an average of 18.1% and 20.72%, in case of MCB it

shows 10.17% and 15.47%, on MCM it shows 7.60% and 13.04% which also proves that

specimens with MCM holds good resistance than all other specimens. On individual

investigations MCM shows a higher resistance from its initial period of testing due to the

increased percentage of calcite precipitation inside the pores.

Table 2 Durability Test Results-Compressive Strength Loss

[HCL and H2SO4 Immersion]

Spec.

30 Days %

Loss

in Fck

45 Days %

Loss in

Fck

60 Days %

Loss in

Fck

90 Days %

Loss in

Fck

120 Days %

Loss in

Fck B A B A B A B A B A

HCL Immersion – Dosage 40 ml

CC 35.8 34.83 2.71 36.4 30.74 15.55 36.95 30.48 17.51 36.95 27.17 26.47 37.4 26.92 28.02

MCB 41.6 41.0 1.44 41.94 40.2 4.15 42.22 39.64 6.11 42.45 38.82 8.55 42.8 35.2 17.76

MCM 45.9 45.38 1.13 46.41 44.92 3.21 46.96 42.36 9.80 46.96 38.92 17.12 48.0 38.6 19.58

H2SO4 Immersion – Dosage 40 ml

CC 36.2 33.84 6.52 36.8 30.75 16.44 37.85 29.45 22.19 35.83 26.39 26.35 37.4 25.39 32.11

MCB 44.93 42.52 5.36 46.23 43.74 5.39 46.85 41.72 10.95 46.80 37.92 18.97 47.83 36.10 24.52

MCM 46.3 43.12 6.87 45.83 41.43 9.60 45.86 40.28 12.17 47.86 37.90 20.81 47.86 34.50 27.91



Figure 5 Comparison Chart on Compressive Strength loss in HCL

Figure 6 Comparison Chart on Compressive Strength loss in H2SO4

Table 3 and fig 7 illustrates water absorption results on specimens immersed in water.

Specimens of MCM shows a lesser fraction in water absorption from its initial time of testing

ie., 12 hrs to final time of testing ie., 96hrs which range from 1.31% to 3.485% which also

should be noted that it reduces it percentage after 48hrs. In case of MCB and CC specimens

relatively they absorb more water content than MCM specimens ie., MCB in range of 4.22%

to 4.29% and CC specimens in range of 6.86% to 5.41% at its initial and final testing period,

which proved that microbial growths results in sealing of pores and prevention of absorption.

Table 3 Water Absorption Test Results

Spec. Initial

Wt.

Weight After

12 Hrs % of WA 24 Hrs % of

WA 48 Hrs

% of

WA 96 Hrs

% of

WA

CC 2.55 2.725 6.86 2.732 7.13 2.741 7.49 2.688 5.41

MCB 2.582 2.691 4.221 2.698 4.50 2.703 4.68 2.693 4.29

MCM 2..295 2.325 1.31 2.385 3.92 2.390 4.13 2.375 3.485



Figure 7 Comparison Chart on Water Absorption

Table 4 and fig 8 indicates the result for accelerated corrosion test, the test result shows

that, passage of current in all the mixes at different age, conventional concrete cracks at 3rd

day and increase in current consumption is very high, in case of MCB the concrete specimen

cracks at 5th

day after the consumption of current is very high, but in case of MCM it resist for

8th

day, after that we can find the cracks and high range of current consumption, which again

proves that a higher resistance is offered by MCM specimens.

Table 4 Accelerated Corrosion Test Results (*Specimen failed)

Days CC

[Current in mA]

MCM

[Current in mA]

MCB

[Current in mA] Remarks

1 16.5 11 12 -

2 8.5 9 10 -

3 7* 8 7 Cracks visible in CC

4 12 8 7 -

5 15 7 8* Cracks visible in MCB

6 18 7 10 -

7 19 6 13 -

8 22 6* 15 Cracks visible in MCM

9 25 12 18 -

Figure 8 Comparison Chart on Accelerated Corrosion



In Table 5 and fig 9 shows weight loss comparison after the corrosion test were compared

which shows that a greater percentage i.e., 2.87% in CC specimens, 0.23% in MCB

specimens and a lesser fraction of 0.14%b in MCM specimens

Table 5 Weight Loss due to Corrosion

Description Cube Weight in kg

% of Weight Loss Before After

CC 2.641 2.565 2.87

MCM 2.614 2.611 0.14

MCB 2.621 2.615 0.23

Figure 9 Chart represent % of weight loss after Corrosion

In Table 6 load test results shows that conventional concrete records a ultimate of 5.75

tones and 9.6mm deflection, while in case of MCB it records 6.25 tones and 12.3mm which is

8.7% increase in load and 28.1% increase in deflection from CC specimen. On comparing

MCM it records 7.25 tones with 10.5mm ultimate result when compared with CC it increases

by 26.1% in load and 9.4% increase, with MCB 16% increase in load and 14% decrease in

deflection, fig.10. indicates its graphical representation.

Table 6 Load Test Result

Description Load [Ultimate] in

tones Deflection in mm

CC 5.75 9.6

MCM 7.25 10.5

MCB 6.25 12.3



Figure 10 Chart represents Load and Deflection of beams

Fig.11. indicates the SEM images. Detail study on SEM images of MCB and MCM

indicates the type of precipitation inside the specimens, in MCB specimens the precipitation is

carried out in the form of crystals and incase of MCM specimens the precipitation is carried

out in the form of sheets or layers, which induces the strength and durability parameter of all

the tests performed.

(a) MCB (b)MCM

Figure 11 SEM Images

In XRD analysis both the MCB and MCM specimens show the higher level of

precipitation of Calcium Carbonate which turns to be a major factor in activating the

engineering and durability factor. Fig.12. indicates the Precipitation levels on MCB and

MCM specimens.

(a)MCB (b)MCM

Figure 12 XRD on Calcium Carbonate Precipitation in MCB



4. CONCLUSION

• MCM Specimens are found to be more durable to acidic environment than CC

specimen, relatively MCB also proves a better resistance than CC specimens but a

lesser resistance than MCM specimens when immersed in HCL and H2SO4 solution of

5% dosage.

• The discussion on compressive strength shows that MCM and MCB specimens are

more reinforced by Bacterias internally which took more compressive load than that of

CC specimens. MCM turns to be superior on the three specimens.

• Water absorption test results proved that formation of calcite precipitation is highest in

MCM, higher in MCB specimens which resist water absorption in a hopeful way for

sustainability than CC specimens.

• In analyzing Accelerated Corrosion Test MCM, MCB and CC specimens cracks at 8th

,

5th

and 3rd

day which gives a ultimate result of MCM on accelerated corrosion test.

Taking the optimal value in accelerated corrosion the beam elements are casted and

test results which also proves that MCM has the minimum deflection with greater

loads.

• While analyzing SEM and XRD, the calcite precipitation in the form of layers and

crystals with its level, found in MCM and MCB which proves that the better and

strength and durability factor in microbial concrete.

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Documents

CORROSION BASED DURABILITY STUDY IN … constant voltage technique method of corrosion testing is adapted. Specimen size of 100mmx100mmx100mm were cast and steel rod of 150mm was used