Permanent deformation in the form of rutting is one of the major distresses affecting flexible asphalt pavements. This is a serious issue in hot countries and is closely associated with the viscosity of the bitumen binders used. In hot countries, temperatures can exceed 45 °C. Even in the construction of primary roads, bitumen 60/70 (B60/70), which is a relatively low-grade and soft bitumen, continues to be used for Hot Mix Asphalt (HMA) construction. Libyan asphalt concrete pavement roads therefore develop extreme deformations in the form of rutting. This study tests the effects of filler materials on mechanical and volumetric HMA performance with recourse to cellulose fiber (CF) and Ordinary Portland Cement (OPC). CF and OPC were added to a B60/70 HMA mix according to Superpave design specifications. Three percentages of OPC (2%, 4%, and 6%) and three different percentages of CF (0.25%, 0.5%, and 0.75%) were used as filler; there was also a control mix with no filler (0%). Mix performance was assessed with the rutting analyzer and The Indirect Tensile Stiffness Modulus (ITSM). ITSM test were conducted at −5 °C, 10 °C, 25 °C and the rutting analyzer test was conducted at 60 °C to simulate temperatures in the region. The mixes using cellulose fiber performed better than those with OPC. The results suggest potential budgetary savings because roadworks projects can use inexpensive additives instead of more expensive bitumen binders.