What term describes the measure of how easily water flows through aggregate's voids?

The correct term that describes how easily water flows through the voids in aggregate is permeability. Permeability refers to the ability of a material to allow fluids to pass through it. This property is significant in various construction and engineering applications because it affects drainage, water retention, and the overall behavior of materials under different moisture conditions.

Permeability is influenced by several factors, including the size and distribution of the voids in the aggregate as well as the characteristics of the fluid flowing through it. A high permeability indicates that water can flow through the voids with relative ease, while low permeability means that flow is restricted.

While porosity is related to the void space within a material, it specifically refers to the volume of voids in relation to the total volume of the material, rather than the ability of water to flow through those spaces. Hydraulic conductivity also relates to the movement of water, but it incorporates not only the permeability of the material but also the fluid’s viscosity and density. Viscosity, on the other hand, pertains to the internal resistance of a fluid to flow, which doesn’t directly define how water moves through the voids of a solid material like aggregate.