Aggregates

Reservoir Stone

Highest void ratio comes from having uniformly graded aggregate.

Higher permeability comes from larger, angular, uniformly graded aggregate

The important characteristics of the stone within the reservoir or underdrain are the lack of fines, the void ratio and (to a lesser extent) the permeability. Porosity and permeability are directly influenced by the size, gradation and angularity of the particles

The void ratio (e) of a mixture is the ratio of the volume of void-space to the volume of solids. It is closely related to the concept of porosity (n) where porosity is the ratio of the volume of void-space to the total or bulk volume of the mixture. e = Volume of voids/Volume of solids = n/(1-n)

A broad category of particulate material used in construction, including sand, gravel, crushed stone, slag, recycled concrete and geosynthetic aggregates, and available in various particulate size gradations.

Soil particles with a diameter less than 0.050 mm.

The porosity (n) of a mixture is the ratio of the volume of void-space to the total or bulk volume of the mixture. It is closely related to the concept of void ratio (e) where void ratio is the ratio of the volume of void-space to the volume of solids. n = Volume of voids/Total volume of mixture = e/(1+e)