NANOTECHNOLOGY IN CONSTRUCTION
Deals with production and application of
Biological systems at scales ranging from few nanometers to submicron dimensions.
Deals with structures of size 100nm or smaller
One nm is 10^-9 of a meter.
typical carbon-carbon bond length are in range 0.12-0.15nm
DNA has a diameter around 2nm.
bacteria of genus Mycoplasma are around 200nm in length.
Defined as the concrete made with Portland cement particles that are less than 500nm as the cementing agent.
Currently cement particle size ranges from a few nm to a max of 100000nm.
For micro cement avg particle size is reduced to 5000nm.
sol-gel method was used to synthesize each component of Portland cement using nano-particles.
sol is a combination of monomers of solvent-soluble or water-soluble polymers along with a precipitator. Once formed, the sol can be transformed into a gel under similar controlled conditions for temperature, pressure, etc.
In this experiment, the hydration rate for each type of tricalcium silicate component are measured.
When the tri- or di- calcium silicates react with water a calcium-silicate-hydrate gel is formed.
This calcium-silicate hydrate (C-S-H) is the principal hydration product and primary binding phase in Portland cement.
4. component was synthesized by dissolving the solid particles in water and mixing the solution by hand with a metal spatula to form a homogenous sol.
heated on a heat plate at 100Ã‚Â°C for approximately 30 to 40 minutes .
the samples were placed in crucibles and annealed at 1000Ã‚Â°C for 30 min
Finally, the samples were ground to a fine powder using a mortar grinder then placed in glass tubes and sealed with Para Film for protection from moisture
15 mL of de-ionized water was placed in a vacuum flask.
1g of cement was added to the water and the flask was covered with a piece of Styrofoam board.
The water and cement were mixed by shaking the flask and the temperature as a function of time was recorded using data acquisition software.
The sampling rate was set at 10 points/second.
Cylindrical specimens were prepared using PVC pipe, 1.25 cm in diameter and 2.5 cm in length.
The samples were mixed with water, cast in the PVC pipe molds, and covered with thin glass plates.
cured for one day at room temperature and then for 6 days in a moist curing room.
Following the 7-day curing period, the samples were removed and allowed to dry.
Some specimens fractured during the curing process and therefore, could not be tested.
Load and strain data were recorded using data acquisition software.
The loading rate was set at 0.3 inches/minute
It is clear that nanotechnology has changed and will continue to change our vision, expectations and abilities to control the material world.
These developments will definitely affect construction materials.
Large amounts of funds and efforts are being utilized to develop nanotechnology.