Miscibility phase behavior in blends of SBS copolymers (Kraton 1101) and asphalt has been investigated through establishment of thermodynamic phase diagrams. The observed phase diagram of the SBS/asphalt blend is an upper critical solution temperature (UCST) type with a maximum at about 20% copolymer and around 200 degreesC. The study on kinetics of phase decomposition has been carried out by means of time resolved light scattering at the 6/94 Kraton 1101/asphalt composition. Time-evolution of structure factor has been analyzed in the context of temporal scaling laws. The growth regime is seemingly dominated by the late stage of phase decomposition where the hydrodynamic effect is dominant. As typical for a deep off-critical quench, the cessation of domain growth occurs presumably through physical pinning.