This work introduces a novel hydrodynamic model for self-compacting concrete (SCC) design, addressing a key innovation in building materials and construction techniques. The model, derived from the modified packing theory of SCC, comprises five critical steps: (1) determining the maximum particle size (dmax), (2) calculating the maximum volume fraction of the mixture particles Φm, (3) plotting the theoretical particle size distribution curve P(d), (4) assessing the volume of each constituent, and (5) calculating the masses of these constituents. The designed SCC’s physical and mechanical properties are verified through laboratory testing. This method not only enhances the performance of SCC in terms of flowability and stability with a relatively low superplasticizer (SP) amount but also aligns with the emerging trends of prefabrication and modular construction by providing a framework for designing improved SCC mixes that are well-adapted for rapid urbanization and sustainable development. The proposed model contributes to innovations in building materials, offering a practical solution for developing concrete that supports resilient and sustainable urban environments.