nanotechnology in civil engineering

1. 10

2. Nanotechnology in construction
The construction business will inevitably be a beneficiary
of this nanotechnology.
In fact its already in this field of concrete ,steel, glass and
many more.
Concrete is stronger, more durable and more easily placed.
Glass is self cleaning.
Paints are made more insulating and water repelling.

3. Introduction to nano materials
Nanotechnology :- it is defined as a particle with
at least one dimension less than 200nm.it is
quantum dots if they are small enough (typically
sub ion ) such that jump in energy levels occurs.
Nano composite:-it is produced by adding nano
particle to a bulk material in order to improve the
bulk materials properties.

4. Carbon Nano Tubes (CNT)
They are cylindrical with nanometer diameter.
They can be several millimeters in length.
They have 5 times the Young’s modulus and8times
the strength of steel whilst being 1/6 density.
Thermal conductivity is also very high along the tube
axis

5. Titanium oxide
Titanium dioxide is a widely used pigment.
It can oxidize oxygen or organic materials, and so
added to paints, cements, windows tiles. or other
products for sterilizing, deodorizing and anti-fouling
properties.
When incorporated in outdoor building materials can
substantially reduce concentration of airborne
pollutants.
Additnally, as tiO2 is exposed to UV light,it becomes
increasing hydrophilic, thus it can be used for anti
fogging coating or self-cleaning windows.

6. Nanotechnology in concrete
Nanotechnology can modify the molecular structure
of concrete material to improve the materials
properties as shown.
Nano-concrete as “A concrete made with Portland
cement particles that are less than 500 nm as the
cementing agent”.

7. Concrete is, after all a macro- material strongly influenced by
its nano-properties.
Nano-silica particles packing in concrete can be improved by
using nano silica which leads to a dandifying of the micro and
nanostructure resulting in improved mechanical properties.
Nano-silica addition to cement based materials can the
degradation of the fundamental C-S-H(calcium-silicate
hydrate)reaction of the concrete caused by calcium leaching in
water as well as block water penetration and therefore lead to
improvements in durability.
Related to improved particle packing, high energy milling of
ordinary Portland cement (opc)clinker and standard sand.
Produces a greater particle size diminution with respect to
conventional OPC and as a result, the compressive strength
of the redefined of the refine materials also 3 to 6 time higher.

8. if these nano-cement particles can be processed with
Nano tubes and reactive nano size silica particles,
conductive, strong, tough and room temperature
processed ceramics can be developed both for electronic
application and coatings .
Average size of Portland cement particles is about 50
microns.
In thinner final products and faster setting time, micro
cement with a maximum particle size go about 5 microns
is being used.
Therefore is reduced to obtain nano Portland cement.
Hydration test indicates that the nano-cement had a more
rapid hydration rate than Portland cement.

9. TiO2 in concrete
TiO2 is a white pigment can be used as an excellent
reflecting coating.
Its hydrophilic and therefore gives self cleaning
properties to surface to which it is applied.
The proceed by which this occurs is that rain water is
attracted to the surface and forms sheets which collect
the pollutants and dirt particles previously broken down
and washes them off.
The resulting concrete, already used in projects around
the world, has a white color that retains its whiteness
very effective unlike the stained buildings of the material's
pioneering past.

10. CNT in concrete
The addition of small amounts (1%wt) of cnt can
improve the mechanical properties of samples
consisting of the main Portland cement phase and
water.
Oxidized multi-walled Nano tubes (MWNT’s) show
the best improvements both in compressive
strength(+25 N/mm2) and flexural strength(
+8n/mm2)compared to the sample without
reinforcement.
A number of investigation has been carried out
developing smart concrete using carbons fibers.

11. Nanotechnology in steel
Fatigue is a significant issue that can lead to the
structural failure of steel subject to cyclic loading. Such
as in bridges or towers.
This can happen at stresses significantly lower than the
yield stress of the material and lead to a significant
shortening of useful life of the structure.
Stress rise are responsible for initiating cracks from
which fatigue failure result and research has shown that
the addition of copper then limits the number of number
of stress rises and hence fatigue cracking.
Advancements in this technology would lead to increased
safety ,less need for monitoring and more efficient
materials use in construction prone to fatigue issues.

12. Temperature restriction
Above 750F, regular steel starts to lose its structural
integrity, and at 1100 Fahrenheit, steel loses50% of its
strength.
A new formula infuses steel with nanoscale copper
particles, this formula could maintain structural
integrity at temperature up to 1000 F.
The new steel allow ultra high strength to be
combined with good formability, corrosion resistance
and a good surface finish.

13. High strength steel cables
Current research into the refinement of the cementite
phase of steel to a nano size has produce stronger
cables.
A stronger cable material would reduce the cost and
period of construction , especially in suspended
bridges.
Sustainability is also enhanced by the use of higher
cable strength as this leads to more efficient use of
materials.
High rise structures requires high strength joints and
this in turn leads to the need for high strength bolts.

14. Products In Market
Sandvik nanoflex Mmfx2 steel
Produced by sandvik materials
technology Sweden.
Desirable qualities of high
young's modulus and high
strength.
Resistant to corrosion due to
the presence of very hard
nanometer sized particles .
The use of stainless steel
reinforcement in concrete
structures is limited as it is cost
prohibitive.
Produced by mmfx2 steel
corp. America
Has the mechanical
properties of conventional
steel.
Has a modified nano
structure that makes it
corrosion resistant.
It is an alternative to
conventional stainless steel,
but at a lower cost.

15. Vital role of glass in buildings
The current state of the art in cladding is an active
system which tracks sun, wind and rain in order to order
to control the building environment and contribute to
sustainability.
Consequently , there is a lot of research being carried out
on the application of nanotechnology to glass.
Most of glass in construction is, on the exterior surface of
buildings and the control of light and heat entering
through glazing is major issue.
Research into nanotechnological solutions to this centers
around four different strategies to block light & heat
coming thorough windows .

16. Self cleaning glass using TiO2
Titanium dioxide is used in nanoparticle form to coat
to coat glazing since it has sterilizing and anti
fouling properties.
The particles catalyze powerful reactions which
breakdown organic pollutants, volatile organic
compounds and bacterial membranes.
Tio2 is hydrophilic and this attraction to water forms
sheet out of rain drops which then wash off the dirt
particles broken down in the previous process.
Glass incorporating this self cleaning technology is
available on the market today.

17. Self cleaning glass

18. Fire heat protection
Fire- protective glass in another in application of
nanotechnology.
This is achieved by using a clear intumescing layer
sandwiched between glass panels (an interlayer formed ) of
fumed silica(sio2). Nanoparticles which turns into rigid and
opaque fire shield when heated.
For heat protection this film coating are bearing developed
which are spectrally sensitive surface application for window
glass and filter out unwanted infrared frequencies of
light(which heat up a room) and reduce the heat gain in
buildings, however, these are effectively a passive solution.
As an active solution, thermo chromic technologies are being
studied which react to temperature and provide insulation to
give protection from heating whilst maintain adequate lighting
.

19. Nanotechnology and coatings
Nanotechnology is being applied to paints and
insulating properties, produced by the addition of
nano-sized cells, pores and particles, giving a very
limited paths for thermal conduction, are currently
available.
This types of paints are use for corrosion protection
under insulation since it is hydrophobic and repels
water from the metal pipe and can also protect metal
from salt water attack.

20. conclusion
In conclusion , nanotechnology offers the possibility
of great advances where as conventional
approaches at best, offer only incremental
improvements .
“at this moment the main limitation is the high
cost of nanotechnology. Also concerns with the
environmental effects”.
the waves of change being propagated by progress
at the nanoscale will therefore be felt far and wide
and nowhere more so than in construction its large
economic and social presence.

21. NANOTECHNOLOGY AND
CIVIL EGINEERING
DEFINITELY THE FUTURE