Geogrid are made from prime grades of PP and optimum addition of carbon black masterbatch, by the process of extrusion of high quality sheet,accurate punching, and then stretching in two directions under strictly controlled conditions. The process gives well balanced structures with consistently high tensile strength and stiffness. The thick rectangular cross section ribs and integral joint structure give regular apertures that interlock with aggregates, confining them and dramatically improving their load  carrying capacity on soft ground. The products are inert from corrosion by all chemicals, including acids, alkalis and salts normally found in soil and do not suffer from biological attack.