Concrete is a porous material, and the pores are crucial for its strength and durability. In this way, low porosity is the best way to protect concrete against the most aggressive attacks. This study aims to investigate the effect of different additives on the concrete's capillary absorption and breakdown in harsh environments (hydrochloric acid (HCl) and sulfuric acid (H2SO4)) after 30, 90, and 180 days of being completely submerged. To find out how long sand concrete (SC) can stand up to chemical attack, three different mixtures were tested: 10SF5BFS (10% silica fume and 5% blast furnace slag, replaced by the weight of cement), 10SF (10% silica fume), 5BFS (5% blast furnace slag), and SC0 (no substitution as control). These mixtures were selected to investigate the effect of mineral additives SF and BFS on the chemical behavior of SC in a harsh environment. Moreover, the capillary absorption and mass variation of SC were studied. According to the durability results, replacing the cement with 10% SF reduced the capillary absorption by 40%. After 180 days of storage in HCl and H2SO4 acids, 10SF5BFS and 10SF types of concrete offer perfect resistance to chemical attack compared to other concretes.