Civil Engineering Reference
In-Depth Information
+
+
+
+
+
+
+
+
+
+
N
NNN NN
NN N
++++ +
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
Polymer
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
+
+
+
+
+
N
NNN NN
NN N
++++ +
Intercalation
Exfoliation
6.2
Intercalated and exfoliated nanocomposite.
such that the interlayer spacing is expanded, but the layers still bear a well-
defi ned spatial relationship to each other. In an exfoliated structure (Fig.
6.2), the layers of the clay have been completely separated and the indi-
vidual layers are distributed throughout the organic matrix (Nguyen and
Baird, 2007).
With dispersing nanoclay in a thermoplastic material (a material that is
plastic or deformable, melts to a liquid when heated, and freezes to a brittle,
glassy state when cooled suffi ciently), stiffness and tensile strength, tensile
modulus, fl exural strength and thermal stability will increase (Manias, 2001).
The Structures of bitumen and polymers are different as bitumen is a
very complex polymer and not stable. The structure of asphaltenes on
bitumen depends on the chemical composition of the binder and on tem-
perature. In gel type, the asphaltenes are highly associated to each other,
but in sol type, they are not associated to each other and have poor network
and lower asphaltenes proportions and need a different approach to clay
and bitumen interaction which probably limits the successes obtained in
bitumen-nanoclay modifi cations.
6.2 Research on nanoclay-modifi ed asphalt mixtures
Many studies have been carried out on nanoclay-modifi ed polymers, but
little published information is available about nanoclay-modifi ed bitumen.
Many research studies have been performed on bitumen modifi cation by
polymer materials such as SBS (styrene butadiene styrene block copoly-
mer), SBR (styrene butadiene rubber latex) and EVA (ethyl vinyl acetate).
Search WWH ::
Custom Search