World Journal of Engineering The use of nanocomposites to

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World Journal of Engineering
The use of nanocomposites to develop the microstructure and
impermeability of high performance concrete
Saaid. I. Zakia1, Khaled. S. Ragabb and Alaa. M. Rashada
a
: Building Materials Research and Quality Control Institute, Housing & Building National Re search
Center, HBRC, Cairo, Egypt
b
: Rienforced Concrete Research Institute, Housing & Building National Research Center, HBRC, Cairo,
Egypt.
modified fresh and hardened state
properties
when
compared
with
conventional mineral additions. Qing et.
al. [10] reported that nano-silica
accelerated cement hydration process
this led to decrease the setting time of
mortar when compared with silica fume.
Table 2 Properties of nano-SiO2
Description
Results
Diameter (nm)
8-18
Purity (%)
98
Surface area (m2/g)
240
Density (g/cm3)
0.5
Molecular
SiO2
Molecular weight
60.08
1.Introduction
In this new century, the
technology of nano has attracted
considerable scientific interest due to the
new potential uses of particles in
nanometer (10-9 m) scale. The nano
scale-size of particles can result in
significantly improved properties from
conventional grain-size materials of the
same chemical composition. Thus,
industries may be able to re-engineer
many existing products and to design
new and novel products that function at
unprecedented levels. The use of
nano-particles can improve the function
and properties of many types of
materials,
reinforced
plastics,
fire-retardant materials, protective films
or cloths [1] . Nano-SiO2 has been added
to polymer to increase strength,
flexibility and aging resistance [2].
Application of nano-materials into the
production of cement and concrete can
lead to improvements in civil
infrastructure because the mechanical
strength and life of concrete structures
are determined by micro-structure and
by the mass transfer in nano-scale [3].
In Portland cement, when
ultra-fine particles are incorporated into
paste, mortar or concrete materials with
different
characteristics
from
conventional materials were obtained
[4-6]. Previous research [7-9] indicated
that the inclusions of nano-particles
1
Counts/s
40 SF
30
20
10
0
N-Si
40
20
0
10
20
30
40
50
Position [°2Theta]
Fig 1 XRD analysis of SF and NS
Corresponding author: [email protected]
1297
World Journal of Engineering
Fig 3 TEM photographs of NS
Table 3 Details of mix proportions
Mix
Cement
(kg)
SF
(kg)
NS
(kg)
Dolomite
(kg)
Sand
(kg)
Water
(liter)
HRWR
(liter)
Slump
(mm)
M0
M0.5
M0.7
M1
450
447.25
446.5
444.5
100
100
100
100
0
2.75
3.5
5.5
1070
1070
1070
1070
575
575
575
575
192.5
192.5
192.5
192.5
9
11
12
13
20
20
20
20
(cm/sec)
k:coefficient of permeability in (cm/sec).
Q: quantity of accumulated water in
(cm3).coefficient of permeability in
(cm/sec).
t: tested duration time in (sec).
s: surface area that exposed to water
pressure in (cm2).
ϒ: unit weight of water in (g/cm3).
h: maximum penetration depth in (cm).
p: hydrostatic pressure in (kg/cm2).
hydroxide which results additional
formation of calcium silicate hydrate
(C-S-H) gel and more improvement of
interface structure.
The application of nano-SiO2 particles
with newly developed superplasticizer
(polycarboxylic either polymer based
PCE sky) improved the workability and
water tightness of high performance
concrete scince nano-SiO2 interpentrates
polymer network and causes the above
Slump
improvements.
Flow
(mm)
The efficiency of nano-particles such as
57
nan-SiO2 depends on their morphology
55
54
as well as the application of effective
53
superplasticizer which help to disperse
formation of agglomerates and decrease
concrete permeability.
Nano-silica concrete requires additional
amount of superplasticizer.
5.References
1. Ke Y. C. and Stroeve P.,
“Polymer-layered silicate and silica
nanocomposites”,
Amsterdam,
Elsevier B. V., 2005p. 52-55,
330-341.
2. Zhand Q., Wang J. and Cheng S.,
“Study on the CPE/nano SiO2
blends”, J. Funct. Polym., 15
(3),2002, 271-275.
3. Hanehara S. and Ichikawa M.,
“Nanotechnology of cement and
concrete”, Journal of the Taiheiyo
Cement Corporation, 2001, 141,
47-58.
4. Björnström J., Martinelli A., Matic
A., Börjesson L. and Panas I.,
“Accelerating effects of colloidal
nano-silica
for
beneficialcalcium-silicate-hydrate
formation in cement”, Chem. Phys.
Lett., 2004, 392(1-3), 242-8.
Fig 6 Microstructure of nano-SiO2
concrete (M1)
4.Conclusions and recommendations
The properties of concrete are improved
by using Nano-SiO2 where nano
particles fill the voids between cement
grains and consume the part of calcium
1298
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