Carbon nano tubes

1. Compressive strength and microstructure of carbon
nanotubes-fly ash cement composites
Presented by
M. SHIVANJALI
4th year
Under the Guidance of
Dr. M. SRI RAMA CHAND
Assistant Professor
DEPARTMENT OF CIVIL ENGINEERING
SREE CHAITANYA COLLEGE OF ENGINEERING
LMD COLONY, KARIMNAGAR

2. CONTENTS OF PRESENTATION
 Introduction
 Literature Review
 Research Significance
 Objective
 Scope of Work
 Methodology
 Experimental Work
 Materials Used
 Material Properties
 Details of early tests
 Results and Discussions
 Conclusions
 References
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3. INTRODUCTION
 What is Nano Particle:
 According to ASTM the size of nano particles varies from 1 to 100
nanometers(1 Nm=10-9m) in size with a surrounding interfacial layer.
 Tubes and fibers with only 2 dimensions below 100nm are also nano
particles.
 Role of Nano Particles:
 The addition of nano particles in cementitious materials can act as a
filler agent, producing a dense matrix and reduce the growth of micro
pores.
 Addition of nano particles will lead to stronger, more durable, self
healing, air purifying, fire resistant, easy to clean and quick
compacting.
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4. INTRODUCTION
 Carbon Nanotubes (CNT’s) :
 Carbon nanotubes now known to be the materials of 21st century and is
currently receiving a lot of interests due to its extremely high mechanical
properties.
 Carbon nanotubes reported to have a very high theory strength that is
100 times more than steel but yet 6 times lighter and has an ideal
structure formed by carbon tubes.
 CNT’s exhibit extraordinary strength with modulus of elasticity 1TPa and
tensile strength in range of 200 Gpa respectively.
 Due to its high mechanical advantage, carbon nanotubes have been
used in several composites in order to reinforce the matrix.
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5. INTRODUCTION
 The use of CNT’s has been found to improve the properties of polymer-CNTs
composites by increasing the mechanical properties of the composite.
 Carbon nanotubes can be categorized into two major forms:
1. Single walled carbon nanotubes (SWCNT’s) as shown in Fig.1
2. Multi walled carbon nanotubes (MWCNT’s) as shown in Fig.2
 The theoretical minimum diameter of a carbon nanotube is around 0.4 nanometers,
which is about as long as two silicon atoms side by side.
 Average diameters tend to be around the 1.2 nanometer mark, depending on the
process used to create them.
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Fig.1 Single walled carbon nanotubes
(SWCNT’s)
Fig.2 Multi walled carbon nanotubes
(MWCNT’s)

6. INTRODUCTION
 Fly ash:
 Fly ash on other hand, is recognized as an important construction
material due to its environmental benefits(by-product from coal
power plants) and engineering benefits(produce less heat of
hydration, increases workability and improve durability to chemical
attacks such as chlorides and sulphates).
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7. LITERATURE REVIEW
7
Author Title Year Findings
1.Paiva MC et al Mechanical
morphological
characterization of
Polymer Carbon
nanocomposites
from
functionalized
carbon
nanotubes.
2004 The water-soluble PVA–functionalized
carbon nanotubes were then embedded
into PVA matrix via a wet-casting method,
resulting in polymer–
carbon nanocomposite films with
homogeneous nanotube dispersion.
2.Moniruzzaman
et al
Polymer
nanocomposites
containing carbon
nanotubes.
2006 We summarize and critique various
nanotube/polymer composite fabrication
methods including solution mixing, melt
mixing, and in situ polymerization with a
particular emphasis on evaluating the
dispersion state of the nanotubes.
3.Porter A et al Direct imaging of
single-walled
carbon nanotubes
in cells.
2007 Single-walled carbon nanotubes have been
shown to be acutely toxic1,2,3 in a number
of types of cells, but the direct observation
of cellular uptake of single-walled carbon
nanotubes has not been demonstrated
previously due to difficulties in
discriminating carbon-based nanotubes
from carbon-rich cell structures.

8. LITERATURE REVIEW
8
Author Title Year Findings
4.Salvetat et al Mechanical
properties of
carbon
nanotubes.
1999 These are based mainly on the techniques of
high-resolution transmission electron
microscopy (HRTEM) and atomic force
microscopy (AFM) to determine the Young’s
moduli of single-wall nanotube bundles and
multi-walled nanotubes,
5.Srivastava et al Nanomechanic
s of carbon
nanotubes and
composites.
2003 For nanotube-polyethylene composites, we
find that thermal expansion and diffusion
coefficients increase significantly, over their
bulk polyethylene values, above glass
transition temperature, and Young’s modulus
of the composite is found to increase through
van der Waals interaction.
6.Sobolkina et al Dispersion of
carbon
nanotubes and
its influence on
the mechanical
properties of
the cement
matrix.
2012 To obtain a uniform distribution of CNTs in
the cement matrix, the effect of sonication on
the deagglomeration of CNTs in combination
with anionic and nonionic surfactants in
varying concentrations was quantitatively
investigated when preparing aqueous
dispersions of CNTs for the subsequent use
in cement paste.

9. RESEARCH SIGNIFICANCE
 Current pressure to reduce CO2 emissions from the manufacture of
cement is guiding research to use nanotechnology to alter the
processing conditions of cement, therefore reducing these emissions.
 The use of CNT’s leads to increase the use of fly ash content, therefore
resulting in more usage of industrial waste leads to environment safety.
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10. OBJECTIVE
 The main objective of current study is to identify a suitable CNT with
optimum dosage for fly ash cement composites.
 To produce carbon nanotubes-fly ash cement composites for the
first time in order to determine the effect of carbon nanotubes on the
properties of the composites where compressive strength and
microstructure of these mixes were then investigated.
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11. SCOPE OF WORK
 This paper reports on an exhaustive experimental investigation on
the use of CNT-fly ash cement composite with different proportions
of cement, fly ash and CNT combinations.
 100% Portland Cement
 20% Fly Ash +80% Portland Cement
 20% Fly Ash + 80% Portland Cement + 0.5% CNT
 20% Fly Ash + 80% Portland Cement + 1.0% CNT
 The physical and mechanical behaviour of fly ash based cement
composites is determined based on density and compressive
strength tests.
 The microstructural investigation include:
 Scanning Electron Microscope (SEM)
 X-Ray diffractometer (XRD)
 Thermo gravimetric Analysis (TGA)
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Differential Thermal Analysis (DTA)
Energy Dispersive Spectroscopy (EDS)

12. EXPERIMENTAL WORK
 Carbon nanotubes were prepared from chemical vapor deposition (CVD)
method by using nickel oxide as a catalyst.
 Carbon nanotubes were then characterized using a scanning electron
microscope and a room temperature X-ray diffractometer using Ni-filtered
Cu K radiation.
 Fly Ash cement produced from 20% fly ash and 80% Portland cement by
weight was used in the investigation.
 In order to allow comparison 100% Portland cement mix was also
investigated.
 2cm x 2cm x 2cm mortar cubes were casted.
 The ratio of water:cement; blends:sand used was 0.5;1:3 for all mixes.
 The cubes were cured in water at room temperature before being tested.
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13. MATERIALS USED
 Portland Cement
 Fly Ash (by-product from coal power plants)
 Fine aggregate
 Carbon nanotubes
Mix Proportions
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Mix PC(
%)
FA(%) CNT(%) W/C
PC 100 - - 0.5
FA20 80 20 - 0.5
FA20: 0.5CNT 80 20 0.5 0.5
FA20: 1CNT 80 20 1 0.5

14. DETAILS OF EARLY TESTS
 Scanning Electron Microscope (SEM)
 X-Ray diffractometer (XRD)
 Compressive Strength
 Density
 Thermo gravimetric Analysis (TGA)
 Differential Thermal Analysis (DTA)
 Energy Dispersive Spectroscopy (EDS)
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15. Fig. 5. Density results for different samples
RESULTS AND DISCUSSIONS
Micrographs taken from the scanning electron
microscope of the materials used are shown in
fig.3
X-ray diffraction traces of carbon nanotubes are
shown in fig.4
1. The density results of Portland cement mortar,
fly ash cement mortars with and without CNTs
at different ages (1,7,28 and 60 days) are
shown plotted in fig.5.
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Fig. 3. SEM micrographs of (a) Portland
cement, (b) fly ash and (c) carbon nanotubes.
Fig. 4. XRD image of CNT

16. Compressive strength of Fly Ash cement mortars can
be seen in fig.6.
The effect of carbon nanotubes on the compressive
strength of fly ash mortars can be seen in fig.7a.
Relative strength of fly ash-carbon nanotubes to that of
Portland cement mortar was then calculated to give the
results in percentages to that of control PC mortar and
the results can be seen in fig.7b.
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0
10
20
30
40
50
60
7 28 60
PC
20FA
20FA 0.5CNT
20FA 1CNT
Fig.6. Compressive strength of carbon
nanotubes–fly ash cement composites at 7,
28 and 60 days.
0
20
40
60
80
100
120
7 28 60
PC
20FA
20FA 0.5CNT
20FA 1CNT
Fig. 7 a. CS of carbon nanotubes-fly ash
cement composites Fig. 7 b. Relative compressive strengths

17. The corresponding result of fly ash mix
without the addition of carbon nanotubes,
where the calculated results relative to
the mixes without CNT can be seen from
fig.8.
The SEM micrograph can be observed
from fig.9(a-c).
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94
96
98
100
102
104
106
108
110
112
7 28 60
20FA
20FA 0.5CNT
20FA 1CNT
Fig. 8. Relative compressive strength
Fig. 9 SEM images

18.  Table.1 shows the EDS raw data corresponding to the spectrum
given in fig.10. which confirmed the additional CNT phase and the
cement matrix phases.
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Element Wt% Atomic%
C 40.61 54.61
O 32.76 33.08
Al 4.51 2.70
Si 3.30 1.90
S 1.25 0.63
Ca 17.57 7.08
Total 100.00 100.00
Fig. 10. EDS data
Table.1 EDS Raw data

19.  Thermogravimetric and derivative thermogravimetric analyses (TGA
and DTG, respectively) taken at 28 days for FA and FA-CNT
composites are shown in fig.11.
 Differential thermal analysis (DTA) of the two mixes can also be
seen in fig.12.
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Fig. 11. TGA and DT analysis
Fig. 12. DTA graphs

20. CONCLUSIONS
 With the inclusion of CNT’s as fillers, significant effect on
mechanical properties of mortars has been discovered.
 From the SEM micrographs it has been observed that the CNTs
were dispersed uniformly in the cement mortar and there was no
aggregation of CNTs.
 Good interaction between carbon nanotubes and the fly ash cement
matrix with CNTs has been observed which acts as a filler resulting
in a denser microstructure and higher strength when compared to
the reference fly ash mix without CNTs.
 The increase in compressive strength of fly ash mixes has been
observed with increase in carbon nanotubes content with the highest
strength achieved with CNT content of 1% by weight. 20

21. CONCLUSIONS
 Also, under high strain loading rate the compressive strength
increases with the inclusion of CNTs.
 Young's modulus found to be higher than plain cement paste when
the samples were reinforced with CNTs.
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22. REFERENCES
 Paiva, M.C., Zhou, B., Fernando, K.A.S., Lin, Y., Kennedy, J.M. and Sun, Y.P., 2004. Mechanical
and morphological characterization of polymer–carbon nanocomposites from functionalized
carbon nanotubes. Carbon, 42(14), pp.2849-2854.
 Yang, B.X., Shi, J.H., Pramoda, K.P. and Goh, S.H., 2008. Enhancement of the mechanical
properties of polypropylene using polypropylene-grafted multiwalled carbon
nanotubes. Composites Science and Technology, 68(12), pp.2490-2497.
 Moniruzzaman, M. and Winey, K.I., 2006. Polymer nanocomposites containing carbon
nanotubes. Macromolecules, 39(16), pp.5194-5205.
 Yu, M.F., Lourie, O., Dyer, M.J., Moloni, K., Kelly, T.F. and Ruoff, R.S., 2000. Strength and
breaking mechanism of multiwalled carbon nanotubes under tensile load. Science, 287(5453),
pp.637-640.
 Peng, B., Locascio, M., Zapol, P., Li, S., Mielke, S.L., Schatz, G.C. and Espinosa, H.D., 2008.
Measurements of near-ultimate strength for multiwalled carbon nanotubes and irradiation-induced
crosslinking improvements. Nature nanotechnology, 3(10), p.626.
 Filleter, T., Bernal, R., Li, S. and Espinosa, H.D., 2011. Ultrahigh strength and stiffness in
cross‐linked hierarchical carbon nanotube bundles. Advanced Materials, 23(25), pp.2855-2860.
 Sanders, R., 2012. Physicists build world's smallest motor using nanotubes and etched
silicon. Press release). UC Berkeley.
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23. REFERENCES
 Ajayan, P.M., 1999. Nanotubes from carbon. Chemical reviews, 99(7), pp.1787-1800.
 Salvetat, J.P., Bonard, J.M., Thomson, N.H., Kulik, A.J., Forro, L., Benoit, W. and Zuppiroli, L., 1999.
Mechanical properties of carbon nanotubes. Applied Physics A, 69(3), pp.255-260.
 Wei, C. and Cho, K., 2003. Nanomechanics of carbon nanotubes and composites. Applied Mechanics
Reviews, 56(2), pp.215-230.
 Chang, T.P., Shih, J.Y., Yang, K.M. and Hsiao, T.C., 2007. Material properties of Portland cement paste
with nano-montmorillonite. Journal of materials science, 42(17), pp.7478-7487.
 Kuo, W.Y., Huang, J.S. and Lin, C.H., 2006. Effects of organo-modified montmorillonite on strengths
and permeability of cement mortars. Cement and Concrete Research, 36(5), pp.886-895.
 Chappell, M.A., George, A.J., Dontsova, K.M., Porter, B.E., Price, C.L., Zhou, P., Morikawa, E.,
Kennedy, A.J. and Steevens, J.A., 2009. Surfactive stabilization of multi-walled carbon nanotube
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 Sobolkina, A., Mechtcherine, V., Khavrus, V., Maier, D., Mende, M., Ritschel, M. and Leonhardt, A.,
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matrix. Cement and Concrete Composites, 34(10), pp.1104-1113.
 Jiang, L., Gao, L. and Sun, J., 2003. Production of aqueous colloidal dispersions of carbon
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24. Thank you
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