Characteristics of Carbon Nanotube Reinforced Concrete Composites

spyfleaUrban and Civil

Nov 25, 2013 (3 years and 9 months ago)

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Abstract
The mechanical properties of 10 and 20 micron carbon nanotubes (CNTs) in a cementitious
composite are purposed to be studied experimentally. Results may potentially show that the
compressive and flexural strength tests performed at 7 and 28 days for the cementitious
composites with CNTs are higher than those of the cementitious composites with no CNTs.
Therefore, it may be feasible to add nano
-
particles to improve the mechanical properties of
concrete. A scanning electron microscope (SEM) study of the microstructures of the
composites mixed with the CNTs and the composites with no CNTs is believed to show that
the CNTs will filled up the pore space in the composites.
Author Keywords:
Nano
-
particles; Cementitous composites; Microstructure; Mechanical
properties
Keith Andrew
Department of Physics and Astronomy
Applied Physics Institute
Cyber Defense Laboratory
Shane Palmquist
Department of Engineering
Western Kentucky University
Bowling Green, KY 42101
Western Kentucky University
NOVA Center for Nondestructive Analysis
Applied Physics Institute
Characteristics of Carbon
Nanotube Reinforced Concrete Composites
Concrete in Compression
~ 22
o
Concrete fails due to tension
(development of tension cracks),
not compression.

Portland cement

Water

Fine aggregates

Coarse aggregates

Admixtures
Better concrete strengths have been
achieved but little improvement in
ductility has been made (need both).
Surface Area of Concrete Materials
http://www.voyle.net/2006%20Research/Research
-
06
-
046.htm
Microfibers in Concrete
(a)
Four
point
bending
of
a
beam
(b)
Localized
crack
failure
indicating
brittle
behavior
Carbon
Nanotubes
, CNTs
Surendra Shah: Northwestern University
Nanotubes as concrete filler
Nanotubes make concrete
impenetrable to water, salt, etc
.
adding centuries
to the useful life. This can
greatly increase the durability of concrete
.
MS KONSTA
-
GDOUTOS;ZS METAXA;SP SHAH, “
Multi
-
scale mechanical and
fracture characteristics and early
-
age strain capacity of high performance carbon
nanotube/cement nanocomposites
”, Cement & Concrete Composites, (2010)
Synthesis scheme for carbon nanotubes from eutectic melts of aromatic
hydrocarbons undergoing dehydopolycondensation followed by carbonization
reactions
The Molecular Model
Nanolayers of Calcium Aluminate
Diamond is used to cut glass, very rigid steels, sapphire etc. by many aspects,
in spite of their hollow structures, the nanotubes of carbon are even stronger.
As comparison, they are
20 times more rigid in traction than steel even if they
are ten times lighter
. By controlling the growth, the nanotubes can auto
-
organized
in the form of cords. In order for this cord to have the same rigidity as the
nanotubes which make it up, it is necessary to weave the nanotubes between
themselves, in order to prevent the slipping of nanotubes. With very reactive gases,
we can
build very rigid covalent bonds between the nanotubes and to give to
the unit an incomparable rigidity
.
Type of CNTs
SKU #
Single Walled Carbon
Nanotubes
Prices
in grams and kilograms
1g
10g
25g
50g
100g
500g
1kg
Single Walled
Nanotubes
90wt% Prices
0101
95
900
2,125
4,125
8,000
32,500
50,000
Single Walled
Nanotubes
90wt% OH
Prices
0102
150
1,350
2,750
5,000
9,500
42,500
80,000
Single Walled
Nanotubes
90wt% COOH
Prices
0103
150
1,350
2,750
5,000
9,500
42,500
80,000
Short SWNTs
90wt% Prices
0104
150
1,500
3,000
5,500
9,500
47,500
90,000
Read more:
http://www.cheaptubes.com/carbon
-
nanotubes
-
prices.htm#Single_Walled_Nanotubes_Prices#ixzz1BLq6TUMm
Cost and Purity of Commercial CNTs
Model of CNT Failure
Nanotubes ~ 700 x stronger steel ~ 30 x stronger kevlar
Adding 0.05% CNT in foam concrete resulted in:
a.
Lower density
b.
Increased compressive strength
c.
Lower thermal conductivity
d.
Lower average pore diameter
e.
More homogeneous pore wall structure
Results by Other Researchers using CNTs
a. No CNTs
b. 0.05% CNTs c. no CNT d. 0.05% CNTs
SEM Images of Cement Foam Concrete
References
Microstructure of cement mortar with nano
-
particles
Hui Li, Hui
-
gang Xiao, Jie Yuan and Jinping Ou
Harbin Institute of Technology, School of Civil Engineering, Harbin, 150090, People's
Republic of China
Received 10 August 2002;
Revised 20 March 2003.
A study on mechanical and pressure
-
sensitive properties of cement mortar with
nanophase materials
,
Cement and Concrete Research
,
Volume 34, Issue 3
,
March
2004
,
Pages 435
-
438,
Hui Li, Hui
-
gang Xiao, Jin
-
ping Ou
Questions?
Thank you for your time!