Civil Engineering Reference
In-Depth Information
40
2% Cloisite-15A
4% Cloisite-15A
7% Cloisite-15A
2% Nanoill-15
4% Nanoill-15
7% Nanoill-15
30
20
10
0
5
25
40
5
25
40
Temperature (°C)
Temperature (°C)
6.8
Increase in strength and temperature for Cloisite-15A.
40
30
20
0% Cloisite
2% Cloisite
4% Cloisite
7% Cloisite
0% Nanoill
2% Nanoill
4% Nanoill
7% Nanoill
10
0
5
25
40
5
25
40
Temperature (°C)
Temperature (°C)
6.9
Total fracture energy results.
for the higher testing temperatures. There seems to be no major difference
in the effects of adding nanofi ll and cloisite when tested at 5 or 25°C, but
at 40°C and specially when 7% nanoclay is added, Cloisite-15A had
increased the IDT almost twofold compared to Nanofi ll-15.
The area under force versus vertical displacement curve in the ITS test
represents the dissipated energy to crack or fracture the specimen. Two
fracture energy values can be defi ned: fracture energy until failure, which
is the energy dissipated before the specimen starts failing, and total fracture
energy, which is the total energy dissipated to completely destroy the
specimen.
Figure 6.9 shows that addition of nanoclay increases the total energy as
defi ned above. This increase in total energy ranges between 55 and 95% for
nanofi ll and 26 and 72% for cloisite. It can be seen that, at low temperatures
(5°C), modifi ed mixtures need more energy to start the crack initiation as
compared to standard mixture, but when the cracks gets started, less energy
is required to destroy the specimen. At high temperatures (40°C), fracture
energy decreases because of the visco-elasto-plastic behaviour of bitumen.
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