Total porosity in cement and concrete refers to the volume of pore space within the material as a percentage of its total volume. These pores can be intrinsic to the material’s structure or result from the mixing, placing, and curing processes. Porosity is a critical factor because it directly influences the permeability, strength, and durability of concrete. The primary mechanisms that contribute to porosity include the evaporation of excess water used in the mix (capillary pores) and air entrapment during mixing. In hardened concrete, porosity affects how the material interacts with environmental factors such as water ingress, freeze–thaw cycles, and chemical attacks.