Abstract This study presents a numerical approach to estimate the elastic properties of filler-modified asphalt binders using 2D and 3D micro-mechanical modeling and homogenization principles. A three-phase Representative Volume Element (RVE) model was developed to evaluate the elastic modulus and Poisson’s ratio of glass fiber-reinforced polymer (GFRP) powder filler-modified asphalt binders. Periodic boundary conditions were applied to the RVEs, and linear elastic simulations were conducted for 5wt.%, 10wt.%, and 15wt.% filler contents. The results show that elastic modulus is more sensitive to boundary conditions than Poisson’s ratio. Additionally, elastic modulus increases with mesh density, while Poisson’s ratio remains relatively unaffected by mesh size. The choice of mesh type also significantly impacts the elastic properties. High stress concentrations were identified around the glass fiber particles, suggesting potential failure zones. The estimated elastic modulus values for 5 wt.%, 10 wt.%, and 15 wt.% filler content are 3305.42, 3342.72, and 3380.95 MPa, respectively, with corresponding Poisson’s ratio values of 0.3474, 0.3448, and 0.3421. The Halpin-Tsai model, considered more accurate in the literature, shows good agreement with the FEM results, indicating reasonable accuracy.