Conventional asphalt modified by physical mixtures of linear SBS and montmorillonite

The impact of addition of montmorillonite Cloisite (Ca++) and organo-montmorillonite (Cloisite 20A) on the high temperature properties of conventional asphalt modified by linear SBS block copolymer was studied. Linear viscoelastic properties of these materials were probed by small amplitude oscillatory shear flows. Nonlinear properties of prepared materials were studied in start-up shear flows. In the linear viscoelastic domain the presence of organo-montmorillonite was clearly manifested in the dynamic material functions. Similarly, in the nonlinear domain the effect of organo-montmorillonite was seen in the stress response upon start-up of steady shear stress. The first normal stress difference N1 was quite large in these materials. The strong disturbance generated in transient experiments did not destroy the internal structure of materials, and after a sufficiently long resting period the materials returned to their initial structural state.