EFFECTS OF AGGREGATE TYPE, SIZE, AND CONTENT ON …
5-7mm Drainage Aggregate, also known as 5-7mm Crushed River Gravel or CRG, is a natural product used for back-filling trenches, around PVC and Ag-Pipe, and for drainage behind retaining walls.As this is a natural construction product, the colour of the rock varies from a light grey, to blue, to brown in colour.