The number of large-scale projects to satisfy basic human needs has increased with the growth of modern science, demanding an enormous supply of materials, especially high-strength concrete. In this study, rice husk ash (RHA) and ground granulated blast furnace slag (GGBFS) were used to partially replace cement in the production of high-strength concrete incorporating fine sand (HSFSC) to enhance the flexibility, durability, and eco-friendliness of hardened concrete. To determine the optimal mix, an experimental planning method was applied, resulting in 31 mixtures to investigate the effects of water-to-binder ratio (w/b), RHA content, GGBFS content, and superplasticizer (SP) dosage on the workability and compressive strength of HSFSC. Results showed that increasing the w/b ratio, GGBFS content, and SP dosage resulted in a higher slump of fresh concrete, while a lower slump was recorded with higher RHA content. Furthermore, individual factor analysis showed that while higher the w/b ratio reduced the compressive strength of HSFSC, increasing the RHA and GGBFS contents up to a certain level improved the concrete strength, with the SP dosage having the least effect on strength gain. Also, adding more RHA and GGBFS exhibited a positive effect on the strength development of HSFSC while maintaining the w/b ratio and SP dosage. As a result, optimal ranges of 0.25–0.37 for w/b ratio, 12–18% for RHA content, 25–35% for GGBFS content, and 0.6–1.0% for SP dosage were identified by using regression analysis. The experimental tests further confirmed that the HSFSC mixtures had a slump of above 17 cm and a 28-day compressive strength of 73–92 MPa. As a result, the HSFSC specimens with proper GGBFS and RHA contents exhibited relatively good performance in terms of workability, strength development, elastic modulus, and resistance to chloride ion penetration.