Performance
Modification of Asphalt Binders using Thermoplastic Polymers
H.
I. Al-Abdul Wahhab and
The Journal of Engineering Research 1 (2004) 19-8
Abstract:
There
is a need to improve the performance of asphalt binders to minimize stress
cracking that occurs at low temperatures and plastic deformation at high
temperatures. Importation of used asphalt-polymers from abroad, leads to an
increase in the total construction cost as compared to the cost if the used
polymers were of local origin. The main objective of this research was to
modify locally produced asphalt. Ten polymers were identified as potential
asphalt modifiers based on their physical properties and chemical composition.
After preliminary laboratory evaluation for the melting point of these
polymers, five polymers were selected for local asphalt modification. In the
initial stage, required mixing time was decided based on the relation between
shear loss modulus and mixing time. The optimum polymer content was selected
based on Superpave binder performance grade
specifications. The suitability of improvement was verified through the
evaluation of permanent deformation and fatigue behavior of laboratory prepared
asphalt concrete mixes. The results indicated that the rheological
properties of the modified binders improved significantly with sufficient
polymer content (3%). The aging properties of the modified binders were found
to be dependent on the type of polymer. The fatigue life and resistance to
permanent deformation were significantly improved due to enhanced binder rheological properties. Thus, local asphalts can be
modified using thermoplastic polymers.
Keywords: Polymers,
Modified asphalt, Fatigue cracking, Rutting, Roads