The modeling of the linear viscoelastic behavior of asphalt modified with 8 wt % of partially hydrogenated poly (styrene-butadiene-styrene) triblock copolymers is analyzed. Time-temperature superposition renders master curves in a wide range of frequencies and temperatures, from which a logarithmic distribution of relaxation times is obtained using the multimode Maxwell model. In addition, the linear viscoelastic data is analyzed with an emulsion model and agreement is only found at high frequencies, where the contribution from interfacial tension is negligible. Enhanced polymer-asphalt interactions at low frequencies evidenced by a decreasing limiting slope of the storage modulus in the terminal region are not predicted by the emulsion model, and relative agreement is found considering two viscoelastic phases. The Cole-Cole representation and the fractional Maxwell model predict the viscosity of asphalt in the complex plane, but strong asymmetry in the semicircular arcs is found in the polymer-modified asphalt blends. The Havriliak-Negami model accounts for asymmetric arcs and represents the data better in specific ranges of frequency.
展开▼
