Although several warm-mix asphalt projects have been explored in the USA, Europe, and some countries in Asia, there is a need for the research to evaluate the applicability of warm-mix asphalt in Thailand. In this study, the fundamental properties of bitumen modified with one of the commonly used additives (Sasobit, a long-chain aliphatic hydrocarbon (LCAH)) were evaluated. The properties evaluated included the viscosity, rheological properties, rutting, and fatigue resistance. In addition, the compactability of the mixtures was also investigated to determine whether they could reach the desired density at lower temperatures. It was found that the LCAH modification improved the workability and the fundamental properties of bitumen as shown in better rutting and fatigue resistance, and also in higher complex shear modulus. The measurement of the compactability showed that less energy was required to compact the LCAH-modified asphalt mixtures to the desired density even at 20–40°C below compaction temperature. The mixtures modified with the LCAH had greater resistance to densification under traffic or higher potential to resist permanent deformation. The LCAH had no effect, however, on the resistance of asphalt mixtures to moisture damage, but the reduction of mixing and compaction temperatures could have a detrimental effect on the moisture sensitivity.