carbon black as an additive in concrete

WASTE CARBON BLACK AS A
FILLER MATERIAL IN CONCRETE
SEMINAR REPORT
Submitted in partial fulfilment of
the requirements for the award of B.Tech Degree in
Civil Engineering
of Mahatma Gandhi University
during 2014-2018.
Submitted by,
GAYATHRY.T.J
Reg. No: 14001117
Guided by,
SANTHI.G.NAIR
Professor
DEPARTMENT OF CIVIL ENGINEERING
ADI SHANKARA INSTITUTE OF ENGINEERING & TECHNOLOGY
KALADY
SEPTEMBER 2017

ADI SHANKARA INSTITUTE OF ENGINEERING&TECHNOLOGY
KALADY
DEPARTMENT OF CIVIL ENGINEERING
Certificate
This is to certify that this seminar report entitled “WASTE CARBON BLACK AS A
FILLER MATERIAL IN CONCRETE”is a bonafide record of the seminar presented
by GAYATHRY.T.J (Reg.No:14001117) under our guidance towards the partial
fulfillment of the requirements for the award of the degree of Bachelor of Technology in Civil
Engineering of Mahatma Gandhi University during 2014-2018.
Prof. Santhi.G.Nair Dr.R.Radhakrishnan
Professor Assistant Professor Head of the Department
(seminar guide) (seminar coordinator) Department of Civil Engineering
Place: Kalady
Date: ………….

DECLARATION
I declare that this written submission represents my ideas in my own words and where others’ ideas or
words have been included, I have adequately cited and referenced the original sources. I also declare that
I have adhered to all principles of academic honesty and integrity and have not misrepresented or
fabricated or falsified any idea/data/fact/source in my submission. I understand that any violation of the
above will be cause for disciplinary action by the Institute and can also evoke penal action from the
sources which have not been properly cited or from whom proper permission has not been taken when
needed.
Gayathry.T.J
(Reg.No:14001117)
Date:13/09/2017

ACKNOWLEDGEMENT
I am greatly indebted to my guide Prof.Santhi.G.Nair, Professor, Department of Civil
Engineering, Adi Shankara Institute Of Engineering & Technology ,Kalady, for her patient and
sincere guidance.
I am grateful to my Seminar Coordinators Mrs.ChitraC.J and Mrs. Martina Poulose,
Assistant Professors, Department of Civil Engineering for their valuable guidance and
suggestions.
I also thank Dr. P.C. Neelakantan, Principal, Adi Shankara Institute of Engineering&
Technology, Kalady and Dr.R.Radhakrishnan, Head of the Department, Civil Engineering for
providing me all the required facilities.
I would also like to thank my parents for their support and love. I also acknowledge my
gratitude to other members of faculty in the Department of Civil Engineering and all my friends
for their whole hearted encouragement and support.
Above all I thank God Almighty for bestowing his blessings on me.
I perceive this opportunity as a big milestone in my academic life and I will strive to use
my newly gained skills and knowledge in the best possible way.
GAYATHRY.T.J
iii

ABSTRACT
Concrete is the essential construction material used for many applications in the
construction industry. Though it is used worldwide, it has its ill effects like the presence of pores
and micro-cracks. These ill effects lead to acid intrusion and less resistance to atmospheric
attack. As a result, its durability and strength get reduced. The current tendency in the world is to
find new materials at lower cost which can guarantee better performances during their
incorporations in the concrete. Usage of waste materials for construction purpose enhances the
traditional methods of construction. The effect of addition of carbon black powder, a waste from
rubber industry as a filler material in concrete is investigated. Study on uniformity, surface
hardness, split tensile strength, flexural strength and compressive strength of concrete specimens
containing various percentages of carbon black were carried out. The effect of added carbon
black to concrete mix on corrosion of steel reinforcement was studied. This was achieved by
inserting steel bars in different concrete mixes containing 0.1, 0.2, 0.3, 0.4, and 0.5, carbon
black/cement. Carbon black as a filler enhances the performance of concrete.
Keywords
Carbon black,Filler,Pores,Microcracks,Corrosion resistance
iv

CONTENTS
SECTION PAGE NO
ACKNOWLEDGEMENT iii
ABSTRACT iv
LIST OF FIGURES vii
LIST OF TABLES viii
1 INTRODUCTION 1
1.1 General 1
1.1.1 Ingredients 1
1.2 Properties Of Concrete 2
1.3 Proportioning Of Concrete 4
1.4 Advantages Of Concrete 6
1.5 Disadvantages Of Concrete 6
1.6 Objective Of Study 7
2 LITERATURE REVIEW 8
3 METHODOLOGY 10
3.1 Compressive Strength Test 10
3.2 Rebound Hammer Test 11
3.3 Ultrasonic Pulse Velocity Test 12
3.4 Split Tensile Strength Test 13
3.5 Open Circuit Potential Test 14
4 CASE STUDY 15
4.1 Case Study 1 15
4.1.1 Experimental Program On Carbon Black Concrete 15
4.1.2 Materials Used 15
4.1.3 Experimental Setup And Testing Of Specimens 16
4.1.4 Results And Discussion 24
4.2 Case Study 2 25
4.2.1 Material Used 25

4.2.2 Mix Design 26
4.2.3 Preparation Of Test Specimens 27
4.2.4 Test Procedure 27
4.2.5 Results And Discussion 29
5 SUGGESTIONS FOR FURTHER STUDY 31
6 CONCLUSION 32
REFERENCES 33

LIST OF FIGURES
TITLE PAGE No
Fig1.1 Carbon Black 7
Fig 3.1 Rebound Hammer 11
Fig 3.2 Method Of Measuring Pulse Velocity 12
Fig 3.3 Splitting Tensile Strength Test Setup 13
Fig 3.4 Open Circuit Potential Test 14
Fig 4.1 Result Obtained From Particle Size Analysis 16
Fig 4.2 Experimental Setup Of Compression Test 17
Fig 4.3 CB Concrete Cubes 17
Fig 4.4 Compression Test Results For Concrete Cubes 18
Fig 4.5 Experimental Setup Of Rebound Hammer Test 18
Fig 4.6 Rebound Hammer Test Results For Concrete Cubes 19
Fig 4.7 Experimental Setup Of Ultrasonic Pulse Velocity Test 19
Fig 4.8 Ultrasonic Pulse Velocity Test Results 20
Fig 4.9 Split Tensile Test Arrangement 21
Fig 4.10 Split Tensile Strength Test Results 22
Fig 4.11. Open Circuit Potential Test Results 23
Fig 4.12 PET 26
Fig 4.13 Carbon Black 26
Fig 4.14 Casting Of Cube 27
Fig 4.15 Casting Of Cylinders 27
Fig 4.16 Compression Test Setup 28
Fig 4.17 Split Tensile Strength Test Setup 28
Fig 4.18 Average Compressive Strength 29
Fig 4.19 Average Split Tensile Strength 30
vii

LIST OF TABLES
TITLE PAGE NO
Table1.1 Grades Of Concrete And Their Uses 5
Table 4.1 Compressive Test Results 17
Table 4.2 Rebound Hammer Test Results 19
Table 4.3 Ultrasonic Pulse Velocity Test Results 20
Table 4.4 Split Tensile Test Results 21
Table 4.5 Relation B/W Opc Values And Corrosion 23
Table 4.6 Mix Design 26
Table 4.7 Compressive Strength At 28 Days 29
Table 4.8 Split Tensile Strength At 28 Day 30
viii

Carbon black as a Filler in Concrete
Dept. of Civil Engineering, ASIET,Kalady
1
CHAPTER 1
INTRODUCTION
1.1 General
Concrete today is the most versatile material for all types of construction works and has
been used for innumerable construction works either as plain concrete or as reinforced cement
concrete or as precast concrete or pre stressed concrete or in many other forms. In building
industry the concrete is mainly used for beams, slabs, staircases, lintels, storage tanks, etc.
Cement concrete is an artificial building material which is obtained by mixing together certain
inert materials called coarse aggregate and fine aggregate with active constituents like cement
and water.The mixture is in a plastic condition,when allowed to set becomes hard as stone.The
strength of cement concrete depends on its ingredients ,their relative quantities and the manner in
which they are mixed and placed.By suitably adjusting the proportions of cement,coarse
aggregate,fine aggregate and water it is possible to get the concrete of sufficient compressive
strength for various uses.Because of high strength capability in compression,the concrete is
considered to be a versatile material and it is used as a tough mix for road construction,as a rich
mix for heavy structural members,viz.,columns,gravity dams,etc and as a lean mix for
foundation.For this reason and due to many other advantages,such as high durability,better
appearance,ease of construction,economy,etc the cement concrete is considered superior to other
materials and hence is being extensively used for construction of modern structures.Plain cement
concrete has very little tensile strength and hence to withstand the tensile forces it has to be
reinforced in structures usually by steel.Cement concrete is classified into plain cement
concrete,reinforced concrete,vibrated concrete,precast concrete,prestressed concrete.
1.1.1 Ingredients
Although there are many materials in the preparation of different kinds of concrete,there
are only three basic constituents.They are binding matrial like cement,aggregates like sand or
broken stone and water.
1. Cement:Cement is the product obtained by burning a well proportioned mixture of
Siliceous,Argillaceous and Calcareous materials and crushing the same into a fine

2
powder,the cement water paste has its characteristic properties of adhesion and cohesion
by which it can bond well with aggregates to form a strong rock like mass called concrete
as a consequence of chemical reaction between cement and water.Nowadays a majority
of the cement concrete work in building construction is done with Ordinary Portland
Cement.Other types of cement such as rapid hardening cement and high alumina cement
are also used under certain circumstances.
2. Aggregates:They are granular materials chemically inert such as natural
sand,gravels,crushed stones or air-cooled iron blast furnace slag .These are used as filler
in concrete and mortar for economy in construction.These are also known as inert
fillers.It avoids cracking and gives more strength to concrete.The aggregates which are
bound by means of cement,forms the bulk of concrete.Both fine and coarse aggregates
are used in concrete.Hard,durable and clean aggregates are to be used for this.It should be
free from organic and vegetable matter,clay,fine dust,etc.The presence of such impurities
prevents adhesion of aggregates and hence reduces the strength of concrete.
3. Water:Water is an important ingredient of concrete,because hydration takes place only in
the presence of water.The water which is used in concrete should be clean and free from
harmful impurities such as oil,alkali,etc.In general water used in concrete should be fit for
drinking.The water added as an ingredient in concrete has the following functions:
 The water reacts with cement,which causes the setting and hardening of concrete.
 It acts as a lubricant between the aggregates and it facilitates the passage of
cement to the voids of aggregates.
The amount of water added to concrete determines the properties of concrete.The ratio of
the amount of water to the amount of cement by weight is called water cement ratio.
1.2 Properties Of Cement Concrete
1. Strength Of Concrete:It should have high compressive strength.The tensile and shear
strength are generally about 8 to 12% and 8 to 10% of their compressive strength
respectively.The compressive strength of concrete is influenced by several factors such as
quality of materials,water cement ratio,age of concrete,cement content,grading of
aggregatesmethod of mixing,placing compacting and curing.
2. Workability Of Concrete: The concrete should have sufficient workability. The
workability of concrete indicates the ease with which it can be mixed, placed and

3
compacted. The degree of workability for different forms of concrete work is
specified.Generally strength decreases with increase in degree of workability and vice-
versa.
3. Durability Of Concrete: The durability of cement concrete is defined as its ability to
resist weathering action, chemical attack, abrasion or any other process of
deterioration.Durable concrete will retain its orginal form,quality and serviceability when
exposed to the environment.The concrete possesses a high durability value,as it is not
much affected by atmospheric actions.On the contrary with age,the concrete goes on
hardening,thereby increasing strength.It is this property,which gives concrete a distinct
place among building materials.
4. Elasticity Of Concrete:The concrete is not a truly elastic material and elasticity modulus
is influenced by strength,age and moisture content of the concrete and the type of
aggregate used.The concrete undergoes an extra strain in addition to instantaneous
strainon application of load or stress,for sufficient time.This extra strain is called ‘creep
of concrete’ and is permanent in character.
5. Shrinkage Of Concrete: The concrete has a tendency to shrink under the following two
conditions:
 There is initial shrinkage of cement concrete which is mainly due to loss of water
through forms, absorption by surfaces of forms, etc.
 The shrinkage of cement concrete occurs as it hardens. This tendency of
shrinkage on one hand causes cracks in concrete, while on the other, it grips the
reinforcement tightly and hence proper bond between concrete and reinforcement
when used in R.C.C work.
6. Fire Resistance Of Concrete: Concrete is a good insulator and has a fairly good fire
resistance owing to the presence of pores and also water.
7. Other Properties:
 When used with steel in R.C.C work , it can withstand both compressive and
tensile stresses, hence more utility.
 It is free from corrosion.
 It forms a hard surface, so capable of resisting abrasion.
 Concrete is proved to be economical than steel.

4
 Purpose made types of concrete further enhances its utility, viz .vibrated concrete
for high compressive strength;light weight concrete for fire resistance and
partitions;vacuum concrete for more strength; lime concrete for economy.
1.3 Proportioning Of Concrete
Proportioning is essential to ensure that the concrete produced meets the requirements of
the job.The standards specify the properties of concrete mixes which have been found suitable
for different structures.To comply with these standards and for making best use of materials,one
should see that the various constituents namely cement,water,fine aggregate, coarse aggregate
and admixture , if any should be so chosen and mixed that the resulting concrete meets the
following properties:
1. Strength:When hardened the concrete should have sufficient strength to bear the imposed
stresses (loads) safely with the required factor of safety.
2. Durability:The concrete must be durabvle with proper regard to weather conditions to
which the structure will be subjected.
3. Workability:While fresh,the concrete must be workable enough for economical and
uniform placing but not excessively fluid.
4. Economy:The cost of preparation of concrete should be minimum possible.Particularly
the use of cement should be minimum with due regard to first three properties.
Concrete mixes are of two types.Nominal mix are of fixed proportions.Concrete can be
designed to produce a desired grade of concrete with required characteristic strength and
workability.This type of designed concrete mix is called design mix.The design of mix requires
complete knowledge of the properties of the constituent materials and the inter relations between
them.The different methods commonly adopted for designing the concrete mixes are American
Concrete Institute (ACI) method,Road Note No.4 method(Grading Curve Method),IS Code
method, IRC-44method.The design involves arriving at a suitable proportion of the constituent
materials.For any grade above M25,design mixes are recommended.Where M refers the mix and
the number specifies the compressive strength of 15cm concrete cube tested after 28 days in
N/mm2.The characteristic strength for various grades of concrete and the approximate
proportions and uses are given in the table below.

5
Table 1.1: Grades Of Concrete And Their Uses
GRADES OF CONCRETE PROPORTION
OF CONCRETE
USES
M5 1:5:10 Mass concrete works for strong walls
and foundations
M7.5 1:4:8 Mass concrete for strong walls and
foundations
M10 1:3:6 Mass concrete works like culverts
and retaining walls ,flooring
M15 1:2:4 Plain cement concrete works
M20 1:1.5:3 For general R.C.C works in building
such as
stairs,beams,columns,piles,etc.
M25 1:1:2 Water retaining
structures,piles,precast products,etc.
M30 Design mix Heavily loaded R.C column and
R.C.C arches of long span
M35 onwards Design mix For pre stress concrete works

6
1.4 Advantages Of Concrete
1. Fresh concrete can be moulded into durable structural members of various size and
shape.
2. It has sufficient plasticity for working.
3. Ingredients of concrete are locally and easily available.
4. It can be easily transported from the place of mixing to the site where it is loosed.
5. It can be easily pumped to fill cracks and other small places for repair work.
6. It hardens with age .Hardening continue for a long time.
7. Hardened concrete has high compressive strength.
8. It is free from corrosion and less affected by atmospheric agent.
9. It forms a hard surface capable of resisting abrasion.
10.It is a good sound proofing material.
11.It proves to be more economical than other material.
12.It’s maintenance cost is also less.
13.Concrete structures are more durable and not liable to decay.
14.Concrete members have better rigidity and appearance.
15.Concrete can be reinforced with steel and any type of members are made.
16.High quality control is possible. Property can be altered by appropriate ingredient and
by special processing techniques.
17.Complete mechanisation is possible in preparation and placing process.
1.5 Disadvantages Of Concrete
1. The rapid production of cement used in concrete creates big problems to environment.
According to the estimation, 1 ton of carbon dioxide is released to the atmosphere when 1
tone of OPC is manufactured.
2. Also due to its high permeability, concrete undergo corrosion by penetration of carbon
dioxide (CO2) and chlorine. This weakens the concrete and reduces its service life. This
subsequently increases costly maintenance on repair and restoration projects for the
damaged concrete structure.
3. Concrete is weak in tension.
4. It has a tendency to shrink.

7
5. Due to its low tensile strength it has to be reinforced which increases the cost.
6. Its coefficient of expansion is large which leads to cracks in large concrete structures.
7. Soluble salts presents in concrete experience efflorescence.
8. Concrete structures are heavy in weight.
9. Concrete needs more time to cure and to develop the needed strength and are not suitable
for speedy construction.
1.6 Objective Of Study
The presence of pores in concrete proves to be a major problem ever since it was
discovered. Pores in turn attract water that leads to various ill effects such as freezing and
thawing, acid intrusion, decreased resistance to chloride ion, reduced compressive strength etc.
By considering this problem, a study is made to minimize the pores present using carbon black
powder, a waste from rubber industry as filler and suggest the optimum percentage of carbon
black to be added in concrete for its enhanced performance . For this a study on uniformity,
surface hardness, split tensile strength, flexural strength and compressive strength of concrete
specimens containing various percentages of carbon black were carried out. The effect of added
carbon black to concrete mix on corrosion of steel reinforcement was also studied.
Carbon black is virtually pure elemental carbon in the form of colloidal particles that are
produced by incomplete combustion or thermal decomposition of gaseous or liquid hydrocarbons
under controlled conditions. Its physical appearance is that of a black, finely divided pellet or
powder. The specific gravity of carbon black is 1.33 and pH value 6. This indicates that carbon
black is almost an inert material.
Fig1.1:CarbonBlackPowder

8
CHAPTER 2
LITERATURE REVIEW
Goldman A, Bentur A. (1993) Many research works have been carried out by using
various materials such as mica, silica, glass micro spheres, fake glass, etc. as filler in
concrete. The effectiveness of using waste carbon black as filler in concrete has been
previously studied since 1993. Goldman and Bentur studied the influence of microfillers on
the enhancement of concrete strength and proposed that carbon black is non-reactive inert
material. They also commented that compressive strength is more of concrete with smaller
particle size carbon black (0.073 and 0.025 micrometer) compared to the larger particle size
of 0.33 micrometer. Goldman and Bentur proposed that carbon black, non-reactive filler is
highly effective in improving the mechanical performance of concrete. Their work indicated
that improved mechanical properties are due to densification of the transition zone.
Dr.G.Chitra,P.Vetri Selvi,Dr.D.Vijayalakshmi(2014) Experimented on an minimizing
the presence of pores in conventional concrete using carbon black powder, a waste from
rubber industry as filler. Carbon black filler material imparts the enhanced performance of
concrete. To suggest the optimum percentage of carbon black to be added in concrete totally
18 number of concrete cubes, 12 number of concrete cylinders with carbon black of different
percentage (0%, 2%, 5%, 8%, 12%, 15%) were cast. Study on morphology, surface hardness,
uniformity, compressive strength, tensile strength and water absorption were carried out on
carbon black concrete specimens. A Comparison is made with test results to arrive at valid
conclusion. It can be observed that the specimens with 2% and 5% carbon black show good
performance with respect to control specimens.
Masadeh, S. (2015) The effect of added carbon black to concrete mix on corrosion of
steel reinforcement was studied. This was achieved by inserting steel bars in different
concrete mixes containing 0.1, 0.2, 0.3, 0.4, and 0.5, carbon black/cement. Samples were
cured, immersed in 3.5% chloride solution for 6 months. Chloride permeability and corrosion
rates were measured. Tests showed that corrosion rate and chloride ions penetration
decreased with increased carbon black content. This was expressed due to filling effect of
very fine particles of carbon black and was in the order less than 250 nm. Tests showed that
corrosion rate and chloride ions penetration decreased with increased carbon black content.
This was due to filling effect of very fine particles of carbon black.
B.Padma priya, Mrs.K.Pandeeswari.M.E.(2016) Investigated the effect of PET
(Polyethylene Terephthalate) on various strength properties. The strength properties of M40
grade concrete are studied with 0%, 10% and 20% of PET. There is decrease in strength
when the ratio of PET to fine aggregate was increased. So that the PET percentage is taken as
constant, the Carbon Black as a partial replaced by cement with 0%, 10%, 20%, and 30%.

9
The strength properties were again studied and its results are compared to conventional
concrete. It was found that there is a decrease in strength when the ratio of PET to fine
aggregate was increased. It is concluded that the carbon black up to 30% as a replacement
of cement will be very effective in concrete.
T.M. Jeyashree,G. Chitra(2017)Conducted a study on uniformity, surface hardness,
split tensile strength, flexural strength and compressive strength of concrete specimens
containing various percentages of carbon black . From the experimental results, it was seen
that optimum percentage of 5% to 8% carbon black can be effectively used for enhancement
of properties of concrete. Influence of adding carbon black as filler material in concrete was
studied by casting and testing the specimens. Flexural behaviour of PCC beam was studied
by conducting flexural strength test. In addition to that, the tests conducted on concrete cubes
were non-destructive testing using Ultrasonic Pulse Velocity (UPV), compressive strength
test using Rebound hammer and the compressive strength test using compression testing
machine. The tests conducted on concrete cylinders were split tensile strength test, OCP Test
and chloride ingress determination test.
Gaurav Navnit Nagavkar(2017) An attempt was made using carbon black powder, a
waste from rubber industry as filler and Calcium Sulphate in the form of hydrate is used as
desiccant to investigate the effect of carbon black and calcium sulphate powder on wet
properties and hardened concrete properties. Both of these additives are partially replaced by
cement with different percentage. Concrete cubes and cylinders are cast depending on
percentage ratio and it’s effect is studied .After mixing carbon black powder and calcium
sulphate as an additive in concrete,its properties like workability, setting time, bleeding,
reactivity, hardness, shrinkage, etc. and other physical and chemical properties gets
integrated.If they are added in accurate and right percentage ratio their bonding matrix acts
more effectively. Also chances of carbon and sulphate attack can be manipulated.

10
CHAPTER 3
METHODOLOGY
3.1 Compressive Strength Test
Compression test is the most common test conducted on hardened concrete partly
because it is an easy test to perform and partly because most of the desirable characteristic
properties of concrete are qualitatively related to its compressive strength.The compression
test is carried out on specimens cubical or cylindrical in shape.Prism is also sometimes
used,but it is not common in our country.Sometimes the compression strength of concrete is
determined using parts of a beam tested in flexure.The end parts of beam are left intact after
failure in flexure and because the beam is usually of square cross section, this part of beam
could be used for finding compressive strength.The cube specimen is of size 15x15x15
cm3.If the largest nominal size of aggregate does not exceed 20mm,10cm size cubes may
also be used as an alternative.Cylindrical test specimens have alength equal to twice the
diameter.They are 15cm in diameter and 30cm long.Smaller test specimens maybe used but a
ratio of diameter of the specimen to maximum size of aggregate ,not less than 3to 1 is
maintained.
Compression test develops a rather more complex system of stresses due to compression
load,the cube or cylinder undergoes lateral expansion owing to the Poisson’s ratio effect.The
steel platens do not undergo lateral expansion to the same extent as that of concrete,with the
result that steel restrains the expansion tendency of concrete in the lateral direction.This
induces a tangential force between the end faces of concrete specimen and the adjacent steel
platens of the testing machine.It has been found that lateral strain the steel platen is only
0.4of the lateral strain in concrete.Due to this the platen restrains the lateral expansion of
concrete inth e parts of the specimen near its end.The degree of restrain exercised depends on
the friction actually developed.When the friction is eliminated by applying grease,graphite or
paraffin wax to the bearing surfaces,the specimen exhibits a larger lateral expansion and
eventually splits along its full length.With friction acting i.e.,under normal conditions of test
,the elements within the specimen is subjected to a shearing stress as well as
compression.The magnitude of shear stress decreases and the lateral expansion increases in

11
distance from the platen. As a result of the restraint in a specimen tested to destruction there
is a relatively undamaged cone.
3.2 Rebound Hammer Test
Schmidt’s rebound hammer developed in 1948 is one of the commonly adopted equipments
for measuring the surface hardness.It consists of a spring control hammer that slides on aplunger
within a tubular housing.When the plunger is pressed against the surface of the concrete ,the
mass rebound from the plunger.It retracts against the force of the spring .The hammer impacts
against the concrete and the spring control mass rebounds ,taking the rider with it along the guide
scale.By pushing a button, the rider can be held in position to allow the reading to be taken.The
distance travelled by mass ,is called the rebound number.It is indicated by the rider moving along
a graduated scale.Each hammer varies considerably in performance and needs calibration for use
on concrete made with the aggregate from specific source. The test can be conducted
horizontally,vertically-upwards or onwards or at any intermediate angle . At each angle the
rebound number will be different for the same concrete and will require separate calibration or
correction chart. Investigations have shown that there is a general correlation between
compressive strength of concrete and rebound number.The relation between flexural strength and
rebound number is found to be similar to those obtained for compressive strength ,except that the
scatter of results is greater.
Fig.3.1:Rebound Hammer

12
3.3 Ultrasonic Pulse Velocity Test
Pulse velocity methods can be sub divided into two parts:
1. Mechanical sonic pulse velocity method,which involves measurement of the time of
travel of longitudinal or compressional waves generated by a single impact hammer blow
or repeated blows.
2. Ultrasonic pulse velocity method which involves measurement of the time of travel of
electronically generated mechanical pulses through the concrete .
Out of these two, the Ultrasonic pulse velocity method has gained considerable popularity all
over the world. Ultrasonic pulse velocity method consists of measurement of the time of travel
of an ultrasonic pulse passing through the concrete to be tested .The pulse generator circuit
consists fo electronic circuit fir generating pulses and a transducer for transforming these
electronic pulses into mechanical energy having vibration frequencies in the range of 15 to 50
kHz.The time of travel between the initial onset and the reception of the pulse is measured
electronically.The path length between transducer divided by time of travel gives the average
velocity of wave propagation.
Fig.3.2:Method Of Measuring Pulse Velocity Through Concrete

13
3.4 Split Tensile Strength Test
This is also sometimes referred as “Brazilian Test”.This test was developed in Brazil in
1943.At about the same time this was also independently developed in Japan.The test is carried
out by placing a cylindrical specimen horizontally between the loading surfaces of compression
testing machine and the load is applied until failure of cylinder along the vertical diameter.The
loading condition produces a high compressive stress immediately below the two generators to
which the load is applied.But the larger portion corresponding todepth is subjected to a uniform
tensile stress acting horizontally.It is estimated that the compressive stress is acting for about 1/6
depth and the remaining 5/6 depth is subjected to tension. In order to reduce the magnitude pof
the high compression stress near the points of application of the load,narrow packing strips of
suitable material such as plywood are placed between specimen and loading platens of testing
machine.The packing strips should be soft enough to allow distribution of load over reasonable
area,yet narrow amd thin enough to prevent large contact area.normally a plywood strip of 25mm
wide and 3mm thick and 30cm long is used.
The main advantage of this method is that the same type of specimen and the same testing
machine used for compression test can be employed for it.That is why it is gaining
popularity.The splitting test is easy to perform and gives more uniform results than other tension
tests.Strength determined in the splitting test is believed to be close to the true tensile strength of
concrete,than modulus of rupture.Splitting strength gives about 5 to 12% higher value than direct
tensile strength.
Fig.3.3:Splitting Tensile Strength Test Setup

14
3.5 Open Circuit Potential Test
The value of either the anodic or cathodic current at Eoc is called the Corrosion Current,
Icorr. If we could measure Icorr, we could use it to calculate the corrosion rate of the metal.
Unfortunately, Icorr cannot be measured directly. However, it can be estimated using
electrochemical techniques. In any real system, Icorr and Corrosion Rate are a function of many
system variables including type of metal, solution composition, temperature, solution movement,
metal history, and many others. In practice, many metals form an oxide layer on their surface as
they corrode. If the oxide layer inhibits further corrosion, the metal is said to passivate. In some
cases, local areas of the passive film break down allowing significant metal corrosion to occur in
a small area. This phenomena is called pitting corrosion or simply pitting. Because corrosion
occurs via electrochemical reactions, electrochemical techniques are ideal for the study of the
corrosion processes. In electrochemical studies, a metal sample with a surface area of a few
square centimeters is used to model the metal in a corroding system. The metal sample is
immersed in a solution typical of the metal's environment in the system being studied.
Additional electrodes are immersed in the solution, and all the electrodes are connected to a
device called a potentiostat. A potentiostat allows you to change the potential of the metal
sample in a controlled manner and measure the current the flows as a function of potential. This
test method covers the estimation of the electrical half-cell potential of uncoated reinforcing steel
in ﬁeld and laboratory concrete, for the purpose of determining the corrosion activity of the
reinforcing steel. This test method is limited by electrical circuitry.
Fig.3.4:Open Circuit Potential Test

15
CHAPTER 4
CASE STUDY
4.1 Case Study 1
4.1.1 Experimental Program On Carbon Black Concrete
This experiment includes the casting of 18 number of concrete cubes of 150x150x150 mm
size and 12 number of concrete cylinders of 150x300 mm size. Hence a total of 30 concrete
specimens were cast with different percentage of carbon black for conducting various tests.
Concrete cubes were cast with the carbon black filler of 0%, 2%, 5%, 8% , 12% and 15% in the
amount of cement, Concrete cylinders were cast with the carbon black of 0%, 2%, 5% and 8% in
the amount of cement. M20 Grade of concrete is used for analysis. In this study, hand mixing
was done. Since carbon black was finding difficulty in blending with the ingredients of concrete,
to obtain a cohesive mix different mixing procedure was adopted. The coarse aggregates, fine
aggregates and water were taken by weight basis and mixed manually on a water tight platform.
Water was added gradually until all the materials were mixed to get uniform mix. After 10
minutes the cement and the remnant of water were added. After 2 minutes of mixing, carbon
black was introduced and mixed for 3 additional minutes.
4.1.2 Materials Used
1 Carbon Black
Carbon black used for the present study is finely divided powder. The specific gravity of
carbon black was determined by density bottle approach, and it was once found to be
1.03. The pH value is 6 and this indicates that carbon black is almost an inert material.
The sources of carbon black are mainly from rubber industry, petrochemical plant and oil
plant . The particle size of carbon black was determined by using particle size analyser,
and graph as shown in Fig.4.1, was extracted. The particle size of carbon black was
found to be 0.05 micrometer.
2 Cement
For the present work 53 grade. The cement used is Portland pozzolanic cement (PPC),
and specific gravity of cement is 2.74. The consistency of cement carbon paste was
found to be 34%. The initial setting time of cement was more than 30 minutes and final
setting time was less than 10hrs.

16
3 Fine Aggregate
The specific gravity was found to be 2.33, and the moisture content was found to be
1.15%. Fineness modulus was 3.544 and as per IS 383 – 1970 [5] fine aggregate used in
the present work belongs to sand zone II.
4 Coarse Aggregate
The specific gravity was found to be 2.78, and the moisture content was found to be
0.33%. The sieve analysis conducted and fineness modulus was 7.767. The bulk density
of coarse aggregate used was 1.513 kg/m3
Fig.4.1:Result Obtained From Particle Size Analysis
4.1.3 Experimental Setup And Testing Of Specimens
To study the performance of carbon black concrete the following tests were conducted :
 Compressive strength test on concrete cubes using compression testing machine
 Non destructive Compressive strength test on concrete cubes using Rebound Hammer
 Ultrasonic Pulse Velocity test to find the Uniformity of concrete
 Split tensile strength test on concrete cylinders using compression testing machine
 Open circuit potential test to find corrosion resistance.

17
1. Compressive Strength Test
Fig.4.2: Experimental Setup Fig.4.3: CB Concrete Cubes
of Compression Test
To determine the compressive strength of concrete cubes, The specimen was placed in the
compression testing machine after curing. The load was applied gradually without shock and
continuously at the rate of 140kg/cm2/minute till the specimen failed. The maximum load at
which the specimen failed was recorded . The result of compressive strength of concrete cubes is
shown in the table .
Table 4.1 Compressive Test Results
% Of Carbon Black Compressive Strength(N/mm2) % increase inCompressive Strength
0% 24.30 _
2% 28.44 +17.03
5% 29.33 +20.7
8% 17.56 -27.73
12% 13.33 -45.14
15% 11.56 -52.42
From the Table and Fig. it is clear that concrete specimen with 2%, 5% has given better results
when compared to control specimen. This shows that carbon black filler increases the strength
of concrete. Among all concrete cubes, 5% carbon black concrete shows the best result. This is
due to densification of transition zone (Transition zone is a thin layer between bulk hydrated

18
cement paste and the aggregate particles in concrete). From 8% onwards the compressive
strength value reduces since carbon black imparts brittle characteristics to concrete.
Fig.4.4: Compression Test Results For Concrete Cubes
2. Rebound Hammer Test
Fig. 4.5:Experimental Setup Of Rebound Hammer Test
This method is based on the principle that the rebound of elastic mass depends on the hardness
of surface against which the mass strikes. The surface hardness and therefore the rebound is
taken to be related to the compressive strength of concrete cubes.

19
Table 4.2 Rebound Hammer Test Results
% Of Carbon Black Rebound No. Compressive Strength(N/mm2)
0% 24.00 19.22
2% 25.50 21.85
5% 28.30 26.21
8% 22.17 17.48
12% 20.50 14.85
The results of rebound hammer test is shown in the Table .From the Table4.2 and Fig.4.6it is
clear that concrete specimen with 2%, 5% has given better results when compared to control
specimen.
Fig.4.6 Rebound Hammer Test Results for Concrete cubes
3. Ultrasonic Pulse Velocity Test
Fig4.7: Experimental Setup Of Ultrasonic Pulse Velocity Test

20
The ultrasonic pulse velocity (UPV) is a non destructive method which is used to establish
the homogeneity of the concrete and to find the presence of cracks, voids and other
imperfections. The method is based on the principle that the velocity of an ultrasonic pulse
through any material depends upon the density, modulus of elasticity and Poisson’s ratio of the
material. Comparatively higher velocity is obtained when concrete quality is good.UPV test was
conducted on concrete cubes to analyze the density, uniformity, homogeneity of carbon black
concrete.
Table 4.3 Ultrasonic Pulse Velocity Test Results
% Of Carbon Black Time
(micro second)
Distance Travelled
(m)
Velocity
(km/s)
% Increase In Velocity
0% 33.55 0.15 4.45 _
2% 31.65 0.15 4.74 +6.0
5% 32.65 0.15 4.59 +2.68
8% 32.05 0.15 4.68 +4.69
12% 32.85 0.15 4.57 +2.23
Fig4.8 Ultrasonic Pulse Velocity Test Results

21
The results of ultrasonic pulse velocity test are shown in the Table 4.3.From the Table 4.3 and
Figure 4.8 it is clear that carbon black filler increases the uniformity of concrete. Among carbon
black concrete specimens 2% shows the best result.
4. Split Tensile Strength Test
Fig. 4.9:Split Tensile Test arrangement
Splitting tensile strength test was conducted on concrete cylinders to determine the tensile
nature of carbon black concrete. The wet specimen was taken from water after 28 days
of curing .The surface of specimen was wiped out. The weight and dimension of the
specimen was noted. The cylinder specimen was placed on compression testing machine.
The load was applied continuously without shock at a constant rate. The breaking load
(P) was noted.
Table 4.4:Split Tensile Test Results Of Cylinders
% of Carbon Black Split Tensile Strength(N/mm2) %Increase In Compressive
Strength w.r.t Control Specimen
0%
18.11 _
2%
13.58 -25.01
5%
15.84 -12.53
8%
11.32 -37.50

22
From the Table4.4 and Fig.4.10 it is clear that the split tensile strength of carbon black
concrete is lesser when compared to that of control specimen. Since carbon black imparts
brittle nature in concrete, this makes the concrete weak in tension.
Fig 4.10 Split Tensile Strength Test Result
5. Open Circuit Potential Test
Specimen
Optimum percentage of carbon black in concrete was obtained from the above-mentioned
tests results. For the optimum percentage obtained(0%,2%,8%), concrete cylinders with rebar
were cast. Concrete cylinders with rebar were used for conducting OCP test.
Experiment
Cylindrical reinforced concrete (1: 1.160: 2.941) specimens of size 150 mm diameter and
300 mm height were cast with and without carbon black powder. Open Circuit Potential
test was conducted as per ASTM C876 . All the specimens were taken out after 28 days
of curing and then dried. Before immersing the specimens in 3.5% NaCl, the potential of
the reinforced bar was measured against saturated calomel electrode (SCE) using a high
impedance volt meter. Then the specimens were subjected to 3.5% NaCl solutions to
induce accelerated corrosion. The potential readings had been measured periodically. The
research was continued for 60 days. The measurements were changed once in a week
due to induced accelerated corrosion. Potential measurements were carried out for both

23
control specimens and carbon black specimens at an ambient temperature of 32+1°C.
Table4.5depicts the relationship between Open Circuit Potential Values and the probability of
corrosion.
Table4.5 Relation B/W OCP Values And Corrosion
Open Circuit Potential(OCP)value(mV vs SCE) Corrosion Condition(As per ASTM C876)
<-426 Severe corrosion
<-276 High(<90% risk of corrosion)
-126 to -275 Intermediate corrosion risk
>-125 Low(10% risk of corrosion)
The result of the open circuit potential test conducted on 0%, 2% and 5% of carbon black
concrete specimens is shown in Fig4.11.From Fig.4.11 it is found that all the specimens are
showing high negative potential values indicating the current condition of the rebar.
Fig 4.11: Open Circuit Potential Test Results
Both the control and carbon black concrete showed the negative potential of more than -50 mV
initially at 7 to 10 days. After that potential, the value of all specimens decreases simultaneously
with increasing number of days. It is also noticed that the corrosion rate of carbon black concrete
is less when compared to the control specimen. The trend in reduction of potential values for
control specimen and carbon black specimen can be observed from the test results.

24
4.1.4 Results And Discussion
1. Compressive strength test results show that 2%, 5% and 8% carbon black specimens have
attained greater strength compared to control specimen. This may be due to densification
of the transition zone . The addition of carbon black beyond 8% reduces the compressive
strength value since carbon black imparts brittle characteristics to concrete.
2. Rebound hammer test was conducted as mentioned in the previous section and test
results show that concrete specimen with 5% shows fairly good surface characteristics
when compared to control specimens. The test result shows that addition of carbon black
as filler in concrete increases the surface hardness of concrete. Among concrete
specimens with carbon black, 5% shows the best performance.
3. The results of ultrasonic pulse velocity test show that quality of concrete cubes with 2%,
5%, 8% and 10% of carbon black is good. This shows that uniformity of concrete is
maintained with the addition of carbon black.
4. Split tensile strength test result shows that the tensile strength of carbon black concrete
is lesser when compared to that of control specimen. Since carbon black imparts brittle
nature in concrete, this makes the concrete weak in tension.
5. OCP test results and chloride show improved performance for carbon black specimens.
Being very fine particle carbon black has closed the pores present in concrete and hence,
the permeability of concrete has been reduced. From the Open circuit potential test results
it can be seen that 5% and 8% carbon black addition is effective in RCC elements.

25
4.2 Case Study 2
4.2.1 Material Used
1.Cement
Cement is the most important constituent of concrete, in that it forms the binding medium for
the discrete ingredients made out of naturally occurring raw materials and sometimes blended
with industrial wastes. The quantity required for this work was assessed and the entire
quantity was purchased and stored properly in casting yard. The cement used in this
experimental investigation is 53 grade OPC conforming to IS 12269: 1987.
2.Fine Aggregate
Fine aggregate used in this investigation is clean river sand without impurities like clay, shell
and organic matters. It is passing through 4.75mm sieve. The fine aggregate were tested, as
per Indian Specifications IS 383-1970. The fine aggregate used in this investigation was
clean river sand and conforming Zone II.
3.Coarse Aggregate
The material retained on 4.75mm sieve is termed as coarse aggregate. Crushed stone and
natural gravel are the common materials used as coarse aggregate for concrete. Well graded
angular aggregate is use and the maximum size of aggregate is 20 mm. the coarse aggregate
were tested as per Indian Specifications IS 383-1970.
4.PET
The waste plastic is being among the most prominent. The waste polyethylene Terephthalate
bottles are recycled and used in industries for different purpose. The recycled waste plastics
in different forms are being use in pavements, bridges, floors, dams and many other civil
engineering works. The advantage of using waste plastic in concrete not only solves the
problem of their safe disposal but also improves the basic properties of concrete like
compressive strength, tensile resistance; impart resistance, permeability, flexural strength,
thermal insulation, etc

26
Fig 4.12:PET
5.Carbon Black Powder
Carbon black is virtually pure elemental carbon in the form of colloidal particles that are
produced by incomplete combustion or thermal decomposition of gaseous or liquid hydrocarbons
under controlled conditions. Its physical appearance is that of a black, finely divided pellet or
powder.
Fig 4.13: Carbon Black
4.2.2 Mix Design
The mix design of M40 grade concrete is calculated using IS 456-2000 and IS 10262-2009. The
material required as per design are given in Table4.6:
TABLE 4.6 Mix Design
W/C
ratio
Quantity of materials(kg/m3)
Cement Fine Aggregate Coarse Aggregate
0.4 380 678 1235

27
4.2.3 Preparation Of Test Specimens
These materials are mixed together, and then they are conveyed to cube mould of size
150 mm X 150 mm X 150mm, cylinder mould of size 150mm X 300mm. After casting, the
specimens were kept for 24 hours and then demoulded. They were cured by water for 28 days.
Fig 4.14 :Casting Of Cube
Fig4.15 :Casting Of Cylinders
4.2.4 Test Procedure
1.Compressive Strength Test
The test is conducted at surface dry condition. The specimens are tested at the age of 7
and 28 days of curing using the Compression Testing Machine. The tests were carried out on a
set of triplicate specimens and the average compressive Strength values were taken.
Compressive strength(N/mm2)=Max load at failurex1000
Loaded surface area

28
Fig 4.16 :Compression Test Setup
2.Split Tensile Strength Test
Splitting tensile strength test was conducted on concrete cylinders to determine the tensile
nature of carbon black concrete. The cylinder specimen was placed on compression testing
machine. The load was applied continuously without shock at a constant rate. The breaking load
(P) was noted.
Split Tensile Strength(N/mm2)= 2 x Breaking load
πxDia of cylinderxL
Fig 4.17 :Split Tensile Strength Test Setup

29
4.2.5 RESULTS AND DISCUSSION
1.Compressive Strength Test
The compressive strength of the specimens with different percentage of carbon black and
PET is given in Table 4.7 from Figure4.18. It is clear that concrete specimen with 30% has
given better results when compared to the control specimen. This shows that carbon black filler
increase the strength of concrete. Among all concrete cubes, 30% carbon black concrete shows
the best result.
Table4.7 :Compressive Strength At 28 Days
Mix Compressive Strength At 28 Days(N/mm2)
M40 46.87
P10CB0 42.93
P10CB10 43.28
P10CB20 44.11
P10CB30 44.86
P20CB0 42.51
P20CB10 45.14
P20CB20 46.01
P20CB30 48.15
Fig4.18: Average Compressive Strength
2.Split Tensile Strength Test
The Split Tensile Strength test results are in the Table III from Figure 6. The Split tensile
strength of the cylinder is seen to be increasing till the 30% of the carbon black. The percentage
of the carbon black with 30% is found to be reasonable with high split tensile strength compared
to the other percentages.

30
Table 4.8: Split Tensile Strength At 28 Days
Mix Split Tensile Strength At 28 Days(N/mm2)
M40 3.48
P10CB0 2.96
P10CB10 3.03
P10CB20 3.11
P10CB30 3.24
P20CB0 2.81
P20CB10 3.26
P20CB20 3.48
P20CB30 3.64
Fig 4.19: Average Split Tensile Strength

31
CHAPTER 5
SUGGESTIONS FOR FURTHER STUDY
1. Investigating the performance of concrete with higher percentage of carbon as filler with
the introduction of binders.
2. Studying the performance of concrete by using carbon black as a replacement for cement.
3. Study effect of CB on cement hydration
4. Study effect of CB on inter transition zone

32
CHAPTER 6
CONCLUSION
1 Concrete today is the most versatile material for all types of construction works.
Conventional concrete has many disadvantages like presence of voids, micro cracks, high
permeability, and shrinkage.
2 Permeability of concrete is often referred as the root cause for lack of durability.
3 A substantial energy and cost savings can result when industrial by products are used as a
partial replacement of cement. The pores present in concrete can be minimized using
carbon black powder, a waste from rubber industry as filler.
4 Due to their extreme small size they can fill the pores thereby increasing the density of
concrete thereby increasing its strength and resistance to atmospheric attack. Also it
helps to decrease permeability of concrete.
5 Carbon Black is a waste from rubber industry, finds difficulty in disposal. Normally
these rubber wastes are dumped into soil creating soil pollution and contamination of
water table.
6 By using carbon black as filler in concrete we can reduce this problem to a great extent.
Thereby reusing the waste usefully and making it eco-friendly to environment.
7 The test results show that performance of 2%, 5% and 8% carbon black concrete is
improved compared to conventional concrete.
8 From the Open circuit potential test results it can be seen that 5% and 8% carbon black
addition is effective in RCC elements.
9 Addition of carbon black beyond 8% is not effective which can be seen from the
reduction in performance of 12% and 15% specimens.
Hence, it is concluded that the addition of carbon black between 5% and 8% as a filler
material will be very effective in enhancing the performance of concrete elements.

33
REFERENCES
1. B.Padma priya, Mrs.K.Pandeeswari.M.E.(2016):”Experimental Investigation on the Properties
of Concrete with Carbon Black and PET”, International Journal of Advanced Research (2016),
Volume 4, Issue 4, 1082-1088.
2.Dr.G.Chitra, P.Vetri Selvi, Dr.D.Vijayalakshmi (2014):”Carbon Black as an Additive in
Conventional Concrete”,International Journal of Emerging Technology and Advanced
Engineering.
3.Gaurav Navnit Nagavkar(2017): “Effect On Properties Of Concrete With Partial Replacement
Of Additives With Cement”,International Journal Of Engineering Sciences & Research
Technology .
4.Masadeh, S. (2015):”The Effect of Added Carbon Black to Concrete Mix on Corrosion of
Steel in Concrete”, Journal of Minerals and Materials Characterization and Engineering, 3,
271-276.
5. T.M. Jeyashree and G. Chitra(2016): “Experimental Studies On Concrete Elements Using
Waste Carbon Black As Filler Material “,Asian Journal Of CivilEngineering(Bhrc),Vol18.

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