Recently, research efforts are being exerted to improve concrete mixture quality while lowering the cost. In this study, pumice rock powder was mixed with cement in varying proportions (10–50%) for the manufacture of concrete mortar samples. The impact of pumice powder additions was examined In terms of the initial and final settling times as well as the compressive strength of the prepared samples. The effect of water additions on the properties of pumice mortar was also investigated. Due to the increasing amounts of pumice rock powder, more water must be added compared to what is required for normal cement paste to create a high-strength concrete mixture. By combining pumice powder with Portland cement, the engineering properties of the concrete mortar samples are enhanced, resulting in a decreased porosity of the prepared samples. The ability of the resulting concrete to absorb water, moisture, and gases is subsequently reduced, providing these combinations an advantage of resistance to harsh environmental conditions. The improved compressive strength together with the decrease in concrete sample density due to pumice additions will lead to a significant reduction in construction costs.