BIO-CONCRETE THE NEXT GENERATION CONCRETE (Report on Bio concrete)

BIO-CONCRETE THE NEXT GENERATION CONCRETE

VISVESWARAYA TECHNOLOGICAL UNIVERSITYBELAGAVI-590 014

Technical Seminar Report

On

“BIO-CONCRETE THE NEXT GENERATION CONCRETE” For I Semester

Master of Technology

In

CONSTRUCTION TECHNOLOGY

By

ASHISH KUMAR D.R

USN: ______________

DEPARTMENT OF CIVIL ENGINEERING

KARAVALI INSTITUTE OF TECHNOLOGY

ENGINEERING COLLEGE

MANGALORE – 575031

2016- 2017

KARAVALI INSTITUE OF TECHNOLOGY, MANGALORE 1


KARAVALI INSTITUTE OF TECHNOLOGY

ENGINEERING COLLEGE

MANGALORE – 575031

DEPARTMENT OF CIVIL ENGINEERING

CERTIFICATEThis is to certify that the technical seminar work entitled “BIO-CONCRETE THE

NEXT GENERATION CONCRETE” is submitted by ASHISH KUMAR .D.R bearing

with USN: ______________ in partial fulfillment for the 4award of degree of Master of

Technology in “Construction Technology” of the Visvesvaraya Technological University,

Belgaum during the year 2016-17. It is to certify that all suggestions and corrections

indicated for the internal assessment have been incorporated in the report. The seminar report

has been approved as it satisfies the academic requirements in respect of seminar work

prescribed for the 1st sem M.Tech degree.

Mr. SACHIN Dr. DASARATHI (M.Tech Coordinator) Professor and Head

Assistant Professor Dept. of Civil Engineering

Dept. of Civil Engineering K.I.T, Mangalore

K.I.T, Mangalore



ACKNOWLEDGEMENT

With great pleasure I wish to express my deep sense of gratitude to my coordinator

Mr. SACHIN, Assistant Professor, Department of Civil Engineering, Karavali Institute of

Technology Engineering College, Mangalore, for his valuable guidance with his

continuous encouragement without which this work would not have been success.

I express my sincere thanks and gratitude to Dr. DASARATHI, Professor and Head

of the Department of Civil engineering, for his help and encouragement.

I would like to thank to our beloved principal Dr. R K BHAT, for his co-operation

during seminar submission.

Finally, I would like to express my heartfelt gratitude to all Faculty members,

K.I.T Mangalore, Family members and Friends, who have directly or indirectly helped me

for the successful completion of this seminar.

ASHISH KUMAR D.R



BIO-CONCRETE

THE NEXT GENERATION CONCRETE

ABSRACT:

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. So there was a need to develop

an inherent biomaterial, a self-repairing material, which can successfully

remediate cracks in concrete. A novel technique in remediating cracks and

fissures in concrete by utilizing microbiologically induced calcite precipitation

(MICP) is a technique that comes under a broader category of science called

biomineralization. It is a process by which living organisms form inorganic

solids. Bacillus Pasteruii, a common soil bacterium can induce the precipitation

of calcite.

This technique is highly desirable because the mineral precipitation

induced as a result of microbial activities is pollution free and natural. As the

cell wall of bacteria is anionic, metal accumulation (calcite) on the surface of

the wall is substantial, thus the entire cell becomes crystalline and they

eventually plug the pores and cracks in concrete.



AN INTRODUCTION TO CONCRETE:

Concrete can be considered as a kind of artificial rock with properties

more or less similar to certain natural rocks. As it is strong, durable, and

relatively cheap, concrete is, since almost two centuries, the most used

construction material worldwide, which can easily be recognized as it has

changed the physiognomy of rural areas. However, due to the heterogeneity of

the composition of its principle components, cement, water, and a variety of

aggregates, the properties of the final product can widely vary. The structural

designer therefore must previously establish which properties are important

for a specific application and must choose the correct composition of the

concrete ingredients in order to ensure that the final product applies to the

previously set standards. Concrete is typically characterized by a high-

compressive strength, but unfortunately also by rather low-tensile strength.

However, through the application of steel or other material reinforcements,

the latter can be compensated for as such reinforcements can take over tensile

forces.

Modern concrete is based on Portland cement, hydraulic cement

patented by Joseph Aspdin in the early 19th century. Already in Roman times

hydraulic cements, made from burned limestone and volcanic earth, slowly

replaced the widely used non-hydraulic cements, which were based on burned

limestone as main ingredient. when limestone is burned (or “calcined”) at a

temperature between 800 and 900°C, a process that drives off bound carbon

dioxide (CO2), lime (calcium oxide: CaO) is produced. Lime, when brought into

contact with water, reacts to form portlandite (Ca(OH)2) which can further

react with CO2, which in turn forms back into calcite (CaCO3), or limestone, the

pre-burning starting material. However, a major drawback of this non-



hydraulic cement is that it will not set under water and, moreover, its reaction

products portlandite and limestone are relatively soluble, and thus will

deteriorate rapidly in wet and/or acidic environments. In contract, Portland

cement produces, upon reaction with water, a much harder and insoluble

material that will also set under water. For Portland cement production a

source of calcium, silicon, aluminum, and iron is needed and therefore usually

limestone, clay, some bauxite, and iron ore are burned in a klin at

temperatures up to 1500°C. The cement clinker produced is mainly composed

of the minerals composed of the minerals alite (3CaO.SiO2), belite (2CaO.SiO2),

aluminate (3CaO.Al2O3), and ferrite (4CaO.Al2O3.Fe2O3), which all yield specific

hydration products with different characteristics upon reaction with water. The

contribution of these clinker minerals to the composition of general-purpose

Portland cement in weight percentage is typically 50%, 24%, 11%, and 8%

respectively. Important characteristics of clinker minerals are reaction rate and

contribution to final strength of the product. For example, of the two calcium

silicates, alite is the most reactive and contributes to early strength. Aluminate

contributes to early strength as its hydration reaction is fast but it also

generates much heat. The final properties of cement-based materials can thus

vary widely as they strongly depend on the mineral composition of the cement

used and therefore, different types of cement, each suitable for specific

applications, are produced. Quantitatively most important hydration product

of general-purpose Portland cement is calcium silicate hydrate (C-S-H), an

amorphous mineral somewhat resembling the natural mineral tobermorite. A

secondary reaction product is calcium hydroxide (portlandite), which together

with the very soluble sodium and potassium oxides (Na2O and K2O) also

present in Portland cement, contribute to the high alkalinity of the concrete’s

pore fluid (pH≈13). The high matrix pH is important in structural concrete as it



protects the embedded steel reinforcement from corrosion. The protective

oxidized thin layer of Fe3+ oxides and oxyhydroxides on the reinforcement steel

(the passivation film) rapidly degrade when the matrix pH drops below 9,

leading to further oxidation and deterioration of the concrete structure due to

expansion reactions and loss of strength. Corrosion of the steel reinforcement

is in fact one of the major causes limiting the durability, or lifetime, of concrete

structures. For further and more detailed information on general concrete

properties the reader is referred to Reinhardt (1958) and Neville(1996).



CONCRETE DURABILITY, DETERIORATION, AND SELF HEALING PROPERTIES:

A variety of additives or replacements of cement can be applied in order

to improve the durability of the final concrete product. Also certain industrial

waste or recycled materials can be used to improve the sustainability, or

environmental friendliness, of concrete and some even improve certain

properties. The production of cement is high-energy consuming as raw

materials are burned at 1500°C, a process that contributes to a significant

amount of atmospheric CO2 release worldwide. Thus, for both economical and

environmental reasons, cement production and use should be minimized.

Examples of industrial waste products, which can partly replace and even

improve cement properties, are fly ash, blast furnace slag, and silica fume. Fly

ash, a waste product from coal-burning power plants, is a source of reactive

silica and can substitute 35-75% of cement in the concrete mix. Application of

fly ash increases concrete strength as it reduces the required water/cement

ratio and also improves resistance against chemical attack as it decreases the

matrix permeability. Similarly, silica fume from the silicon industry and blast

furnace slag from steel industries can partially replace cement in the concrete

mix, as these are source of reactive silica and both reactive silica and calcium

respectively. Other commonly applied additives that improve or change certain

concrete characteristics needed for specific applications are air-entraining

agents to improve freeze/thaw resistance, setting or retarding agents and

plasticizers to enable a lower water/cement ratio to increase concrete

strength.

A number of processes negatively affect the durability and result in the

unwanted early deterioration of concrete structures. One major cause that



initiates various mechanisms of concrete deterioration is the process of

cracking what dramatically increases the permeability of concrete. The

microstructure of hardened cement paste is porous as it contains isolated as

well as interconnected pores. Specifically the connected pores determine

permeability, as these allow water and chemicals to enter the concrete matrix.

As cracking links both isolated and connected pore systems, this results in a

substantially increased permeability. In most concrete-deterioration

mechanisms permeability plays a major role. Intrusion of sulfate ions into the

matrix may result in ettringite formation, a conversion reaction in which a

high-density phase is transformed into a low-density phase, causing expansion

and further cracking of the material. Chloride ions penetrating the matrix

through the connected pore system will destabilize the passivation film of the

steel reinforcement and by doing so accelerate further corrosion. Similarly, in a

process called carbonation, CO2 diffusing through the pore system will react

with alkaline pore fluid components such as Ca(OH)2 which will result in a

lowering of matrix pH and again depassivation of the protective film on the

steel reinforcement. These examples make clear that cracking of concrete

should be minimized and that a potential healing mechanism should ideally

result in the sealing or plugging of newly formed cracks in order to minimize

increases in matrix permeability. An active self healing mechanism in concrete

should be ideal as it does not need labor-intensive manual checking and repair

what would save an enormous amount of money.

A self healing mechanism or self healing agent in concrete should

comply ideally with all, or at least with some, of the following characteristics:



Should be able to seal or plug freshly formed cracks to reduce matrix

permeability.

Must be incorporated in the concrete matrix and able to act

autonomously to be truly “self-healing”.

Must be compatible with concrete, i.e. its presence should not

negatively affect material characteristics.

Should have a long-term potential activity, as concrete structures are

build to last typically for at least 50 years.

Should preferably act as a catalyst and not be consumed in the process

to enable multiple healing events.

Must not be too expensive to keep the material economically

competitive.

Different types of potential self healing mechanisms or agents for autonomous

concrete repair can be thought of. One series of mechanisms could involve the

secondary formation of minerals which are compatible with the material

matrix, i.e. will not negatively affect but rather increase concrete durability by

sealing freshly formed cracks and so decrease matrix permeability. A chemical

agent such as the inclusion of still non-reacted cement particles in the concrete

matrix is feasible as it complies with at least some of the listed self healing

properties. Besides this, other agents could work equally well or can contribute

to the self healing property of concrete in concert with the previous one. Next

to chemicals one could think of an agent of biological origin, and in the next

part the possible application of bacteria as healing agent will be considered.



HOW TO PRESERVE CONCRETE WITH BACTERIA:

CONCRETE is one of the most commonly used building materials. It is

cheap, strong and easy to work with. But, as a short walk through any city

centre will prove, it cracks easily. The cracking of concrete pavements is merely

a nuisance, but cracks in roads, bridges and buildings are a hazard. A way of

making concrete that healed such cracks spontaneously would thus be very

welcome. And a team led by Henk Jonkers at the Delft University of Technology

in the Netherlands may have come up with one.

The way to stop concrete cracking is to bung up small cracks before they

enlarge. That process of enlargement is caused by water getting into a crack,

then freezing in cold weather and thus expanding. This freeze-thaw cycle, a

common form of erosion of natural rocks, too, weakens a structure directly

and also exposes steel reinforcing rods to water, causing them to rust.

When he began his research, Dr Jonkers knew that spraying mineral

producing bacteria onto limestone monuments is often as effective way to stop

freeze-thaw in its tracks. The mineral in question is calcium carbonate, the

defining ingredient of limestone. He also knew, however, that when applied to

concrete, this technique had proved to be just as time-consuming and, indeed,

more expensive than traditional repair methods using sticky, water-repellent

agents. That led him to wonder if the answer was to incorporate helpful

bacteria into concrete from the start.



To find out, he and his team selected various mineral-producing

bacterial strains that can handle the highly alkaline environment found in liquid

concrete. The added these bacteria, along with calcium lactate, an organic

compound that such bacteria convert to calcium carbonate, to different

samples and allowed those samples to set. At various intervals, the team

powdered the solidified samples to set. At various intervals, the team

powdered the solidified samples, created cultures to test for living bacteria,

and ran calculations to determine the number of bacterial cells that had

survived solidification. They also examined samples of the concrete for

concrete for microscopic cracks and to see which minerals had formed.

As they report in Ecological Engineering, Dr Jonkers and his team found

that the mineral grains which formed in the cracks of samples of concrete that

had been seeded with bacteria were often as large as 80 microns across. That

would go a long way towards sealing those cracks and making them

waterproof. The equivalent grains in control samples were rarely larger than 5

microns across.

Unfortunately, this study also showed that the bacteria survive for only a

few weeks. Beyond that period, the concrete falls to heal. But data from a

second study, as yet unpublished, suggest that immobilizing the bacteria in

particles of clay before they are added to the concrete allows them to live for

months, and possibly years. The clay serves both a reservoir for the bacterial

food and also as a haven for the bacteria while the concrete hardens. If the

process can be scaled up, it may be prove that the best way to preserve

concrete is to infect it.



THE SELF HEALING MECHANISM OF BIO-CONCRETE ALSO CALLED AS

BACTERIAL CONCRETE:

Smart structures are those that have the ability to sense certain stimuli

and are able to respond to them in an appropriate fashion, somewhat like a

human being. self healing comes under smart structures, which refers to

structural materials to heal or repair itself automatically upon the sensing of

damage. This ability enhances safety, which is particularly needed for strategic

structures.

Do bacteria exist which could potentially act as a self healing agent in

concrete, and if so, what would be the healing mechanism? From a

microbiological viewpoint the application of bacteria in concrete, or concrete

as a habitat for specialized bacteria, is not odd at all. Although the concrete

matrix may seem at first inhospitable for life, as it is a very dry and extremely

alkaline environment, comparable natural systems occur in which bacteria

thrive. Inside rocks, even at a depth of more than 1km within the earth crust,

in deserts as well as in ultra-basic environments, active bacteria are found

(Jorgensen and D’Hondt 2006; Fajardo-Cavazos and Nicholson 2006; Dorn and

Oberlander 1981; Dela Torre et al. 2003; Pedersen et al. 2004; sleep et al.

2004). These desiccation and/or alkali-resistant bacteria typically form spores,

which are specialized cells able to resist high mechanically and chemically

induced stresses (Sagripanti and Bonifacino 1996). A low-metabolic activity and



extremely along life-times also characterize spores, and some species are

known to produce spores which are viable for up to 200 years (Schlegel 1993).

In a number of recent studies the potential for application of bacteria in

concrete technology was recognized and reported on, e.g. for cleaning of

concrete surfaces (DeGraef et al. 2005) as well as for the improvement of

mortar compressive strength (Ghosh et al.[53]). Moreover, bacterial treatment

of degraded limestone, ornamental stone, and concrete structures for

durability improvement has been the specific topic of a number of recent

studies (Bang et al. 2001; Ramachandran et al. 2001; Rodriguez-Navarro et al.

2003; De Muynck et al. 2005; Dick et al. 2006). Due to bacterially controlled

precipitation of dense calcium carbonate layers, crack-sealing, as well as

significan decreases in permeability of concrete surfaces were observed in

these studies. In these remediation and repair studies the bacteria and

compounds needed for minereal precipitation were brought into contact with

the structures surface after setting or crack formation had occurred, and were

not initially integrated as healing agents in the material’s matrix. The

mechanism of bacterially mediated calcite precipitation in those studies was

primarily based on the enzymatic hydrolysis of urea. In this urease-mediated

process the reaction of urea (CO(NH2)2) and water yields CO2 ammonia (NH3).

Due to the high pH value of the NH3/NH4+ system (about 9.2) the reaction

results in a pH increase and concomitant shift in the carbonate equilibrium

(CO2 to HCO3- and CO2

3-) which results in the precipitation of calcium carbonate

(CaCO3) when sufficient calcium ions (Ca2+) are present.



Precursor compounds were not initially part of the material matrix but

rather externally applied, the remediation mechanism in those studies cannot

be truly defined as self healing. Therefore, in order to investigate the potential

of autonomous bacterially mediated self healing in concrete, a series of

experiments were performed. Firstly, a number of potentially suitable bacterial

species were selected. Four species of alkali-tolerant (alkaliphilic) spore-

forming bacteria of the genus Bacillus were obtained from the Germany. These

bacteria were cultivated and subsequently immobilized in concrete and

cement stone (cement plus water in a weight ratio of 2:1 without aggregate

addition) to test compatibility with concrete and bacterial mineral production

potential respectively. As was listed above (paragraph 2), the ideal self healing

agent should not negatively affect the material characteristics. To test this, a

dense culture of sporosarcina pateurii was washed twice in tap water and the

number of bacteria in the resulting cell suspension quantified by microscopic

counting before addition to the concrete mix makes up water. Two parallel

series of nine concrete bars (with and without bacteria) of dimensions 16X4X4

cm were prepared and triplicate bars of both series were subsequently tested

for flexural tensile and compressive strength after 3,7 and 28 days curing.

Table 1 shows the composition of the concrete mix and Figure 2 depicts the

strength development of both types of concrete in time.

Table 1 Cement, Water, and aggregate composition needed for the production

of nine concrete bars of dimensions 16X4X4cm. the washed cell suspension

used for bacterial concrete was part of totally needed makeup water.



Compound Weight (g)

Cement (ENCI CEMI 32.5) 1,170

Water 585

Aggregate Size Fraction (mm):

4-8 1,685

2-4 1,133

1-2 848

0.5-1 848

0.25-0.5 730

0.125-0.25 396



Fig.2 Flexural tensile (a) and compressive (b) strength testing after 3,7, and 28

days curing revealed no significant difference between control and bacterial

concrete. The latter contained 1.14x 109 S. Pasteurii cells per cubic centimeter

of concrete.



The results of the concrete compatibility test show that the addition of

bacteria to a final concentration of 109 cm-3 does not affect strength

characteristics. Moreover, incubation of cement stone pieces in a medium to

which yeast extract and peptone (3 and 5 g L-1 respectively) was added as a

bacterial food source revealed that on the surface of bacteria-embedded

specimen (Figure 3(B)), but not on control specimen (Figure 3(A)), copious

amounts of calcite-like crystals were formed. From the latter experiment it can

therefore be concluded that suitable bacteria, in this case alkali-resistant

spore-forming bacteria, embedded in the concretes cement paste are able to

produce minerals when an appropriate food source is available.



20X

40X

Figure 3(A)



Figure 3(B)

The mechanism of bacterial mineral production here is likely metabolically

mediated. As the bacteria metabolize the available organic carbon sources

(yeast extract and peptone) under alkaline conditions, carbonate ions are

produced which precipitate with access toward calcium ions present in the

concrete matrix.



Bacteria and calcite crystals



EXPERIMENTAL INVESTIGATIONS:

In the south Dakota School of Mines, the effectiveness of

microbiologically induced calcite precipitation in remediating cracks in

concrete was evaluated by comparing the compressive strength and stiffness

of cracked specimens treated with bacteria and with those of the control

specimens (without bacteria).

For studying the above, cement mortar beams of size 152X25.4X25.4

mm were prepared. The specimens were cured in water for 28 days and then

kept exposed to air for another 3 months. Artificial cracks were cut. The width

of the cracks were 302 mm for all the 10 specimens and the depth of cracks

were 3.2 and 9.5mm. the first 5 specimens were used as control without any

filling in the cracks and were left exposed to air. The cracks in the remaining 5

specimens were filled with a mixture of sand and B.Pasteurii Bacteria. The final

concentration of bacteria in the sand is of the order of 602X1010 cells per ml.

are forced into the crack by knife edge. Then the beams with bacteria in their

cracks were placed in a tray containing urea-CaCl2 medium as food for bacteria

and cured for 28 days. The medium was replaced after 14 days. Extreme care

was taken not to disturb the precipitation of the calcium carbonate during

change of the medium.

The control beams and those of beams with bacteria were tested for

their stiffness after 28 days. It was found that stiffness value of beams whose

cracks were filled with bacteria and sand was higher than those of control

specimens. This was also true for beams with both crack depths. But the

beams with deeper cuts showed comparatively lower stiffness value than the



beams with shallower cuts, meaning thereby the bacterial action and

precipitation did not reach to the full depth of deeper cuts. Shallow cut beams

showed improvements of stiffness by 23.9% while the deep cut beams showed

an improvement of 14% over control specimens.

Appropriate and similar investigations were also conducted with respect to the

following

The effect of microbial calcite precipitation to various depth of cracks on

the compressive strength of cement mortar cubes.

The effect of different concentration of bacterial cells for cracks

remediation, on the compressive strength of cement mortar cubes.

The effect of B.Pasturii with various concentrations on the modulus of

rupture than that of cracked specimens without bacteria.


IMAGINARY BACTERIA AT WORK IN A CRACK


INVESTIGATIONS ON DURABILITY CHARACTERISTICS:

Recently Ramakrishnan et al investigated the durability aspects of

cement mortar beams made with different concentration of bacteria. The main

objective was to determine whether the beams with bacteria performed

better, when subjected to alkaline, sulphate and freeze thaw attack.

They used Scan Electron Microscope (SEM) which is one of the most

versatile instruments available for examination and analysis of micro structural

characteristics of solids.

From the detail investigations they concluded that microbial culture

generated in the cracks of mortar beams increased the compressive strength,

stiffness and modulus of rupture. It was also found that the durability

characteristics improved with the addition of bacteria. SEM examination

established the fact that the calcite precipitation inside cracks has been

responsible for the improvement in mechanical properties and permeability

characteristics for enhancing the durability.

When bacterial concrete is fully developed, it may become yet another

alternative method to replace OPC and its hazardous effect on environmental

pollution.



CONCLUSIONS AND FUTURE PERSPECTIVES:

Some previous studies reported on the successful application of bacteria

for cleaning of concrete surfaces as well as concrete, limestone, and

ornamental stone crack repair (DeGraef et al. 2005; Dick et al. 2006;

Rodriguez-Navarro et al. 2003; Bang et al. 2001; Ramachandran et al. 2001). As

the bacteria in these studies were brought into contact with the material only

after damage had occurred, these examples can not be considered as truly,

autonomous, self healing mechanisms. The experiments presented in this

study, focused on the healing potential of concrete-immobilized bacteria, i.e.

bacteria that are part of the concrete matrix. The results of the experiments

show that immobilized bacteria mediate the precipitation of minerals and,

moreover, the bacteria and certain classes of needed food sources do not

negatively affect concrete strength characteristics. It can therefore be

concluded that bacterially controlled crack-healing in concrete by mineral

precipitation is potentially feasible. The concept, however, needs further

developments on some areas. It should still be clarified whether bacterial

mineral precipitation effectively seals cracks, i.e. significantly reduces the

permeability of cracked concrete in order to protect the embedded

reinforcement from corrosion and thus increases the durability of the material.

Furthermore, bacterial species must be selected which, when part of the

concrete matrix, remain viable for at least the expected lifetime of the



construction. If so, the bacterial approach can successfully compete with other

(a biotic) self healing mechanisms as such bacteria comply with all the listed

characteristics of the most ideal self healing agent


BIO-CONCRETE ALSO CALLED AS BACTERIAL CONCRETE

A SELF-HEALING CONCRETE BY BACTERIAL MINERAL

PRECIPITATION

BACKGROUND:

We do not like cracks in concrete because cracks form an open pathway to the reinforcement and can lead to durability problems like corrosion of the steel rebar. Furthermore cracks can cause leakage in case of liquid retaining structures.


CRACKED WATER RETAINING CONCRETE SLAB



DIFFERENT

HEALING

MECHANISM




MECHANISMS:

Some possible mechanisms for self healing are:

Formation of material like calcite.

Blocking of the path by sedimentation of particles.

Continues hydration of cement particles.

Swelling of the surrounding cement matrix.


ppprpringcpierojfks

CONTROLLED CRACK

FORMATION IN

SMALL SPECIMEN


PRINCIPLE:

The “Bacterial Concrete” can be made by embedding bacteria in the concrete that are able to constantly precipitate calcite.

Bacillus Pasteurii, a common soil bacterium, can continuously precipitate a new highly impermeable calcite layer over the surface of an already existing concrete layer.

The favorable conditions do not directly exist in a concrete but have to be created. A main part of the research will focus on this topic. How can the right conditions be created for the bacteria not only to survive in the concrete but also to feel happy and produce as much calcite as needed to repair cracks.



METHOD: Question to be answered is: what is the ability of the “Bacterial Concrete” to repair the cracks? Both attention will be given on closure of cracks (blocking the path for ingress of water and ions) and on regaining mechanical properties. Cracks in concrete specimen subjected to various loading situations will be investigated before and after the healing. For this impregnation techniques and ESEM will be applied.


IMPREGNATION TECHNIQUES TO IMAGE THE EFFECTOF HEALING



REFERENCE:

CONCRETE TECHNOLOGY BY M.S.SHETTY page no.598

www.esnips.com

www.spiedigitallibrary.com

http://books.google.co.in


http://books.google.co.in/

http://www.spiedigitallibrary.com/

http://www.esnips.com/

BIO-CONCRETE THE NEXT GENERATION CONCRETE (Report on Bio concrete)

Engineering

Transcript of BIO-CONCRETE THE NEXT GENERATION CONCRETE (Report on Bio concrete)