engleski

Rheology of polymer modified bitumen with ethylene vinyl acetate

The Bitumen (BIT) acts as a binder for the mineral aggregates which are laid down and compacted to form an asphalt road. The use of bitumen in paving applications has generated a lot of interests in its rheological properties because of their importance in the manufacture and quality of bituminous pavements. Polymeric additives have been widely used to enhance the in service properties of bitumen. The additions of polymers to obtain polymer modified bitumen dramatically change the rheological properties. The viscoelastic behavior of the modified bitumens containing semi crystalline copolymer ethylene vinyl acetate is presented. The morphology, storage stability and rheological properties of the modified bitumens were studied using fluorescence microscopy, dynamic shear rheometer and conventional tests. The rheological properties of BIT and polymer modified bitumens, PMBs, i.e. complex shear modulus (G*), complex viscosity (*) and phase angle () were measured in the linear viscoelastic range (LVN) and in a broad temperature range at traffic frequency of a 10 rad/s. The critical temperature, i.e. resistance on permanent deformation is done according to SHRP (Strategic Highway Research Program). The resistance of BIT and PMBs on permanent deformation was determined from the equation G*/sin . The results indicated that the morphology and rheological properties of the modified bitumens were influenced by content of the added polymer. Polymer modification improved bitumen rheological properties such as increased G*, * as well as the elastic response. The degree of the improvement generally increased with polymer content. At low polymer contents, the samples showed the existence of dispersed polymer particles in a continuous bitumen phases, whereas at high polymer contents a continuous polymer phase is observed. PMBs have a higher temperature resistance on permanent deformation under traffic frequencies than BIT which means better properties in use in road construction.

BIT; EVA; PMB; Rheological properties; Permanent deformation; Fluorescent microscopy; Storage stability

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