This study evaluates the effect of substituting natural zeolite as a partial replacement for cement in mortar for semi-flexible pavement (SFP) systems, focusing on the mechanical performance and energy dissipation capacity of the mixture. SFP is a composite system that combines a porous asphalt layer with cement mortar to produce a strong, deformation-resistant filled-porous structure. However, the brittle nature of conventional mortar can reduce resistance to cracking under repeated loading. Zeolite, as a natural pozzolanic material, has the potential to improve the mortar’s microstructure and adjust stiffness, thereby enhancing deformation capacity and energy damping. In this study, mortars with various zeolite substitution levels (0%, 5%, 10%, and 15%) were tested for compressive strength and modulus of elasticity. The resulting SFP mixtures were then tested using a fatigue loading method to evaluate energy dissipation. The results show that zeolite substitution at an optimum level can improve the balance between structural stiffness and flexibility, as well as increase energy dissipation capacity. These findings contribute to the development of sustainable pavement materials based on local, environmentally friendly resources. **Keywords:** cement mortar, natural zeolite, cement mortar, compressive strength, energy dissipation