Geotextiles are permeable fabrics which, when used in association with soil, have the ability to separate, filter, reinforce, protect, or drain. Typically made from polypropylene or polyester, geotextiles come in three basic forms: woven (resembling mail bag sacking), needle punched (resembling felt), or heat bonded (resembling ironed felt).

Geotextiles are used in a variety of civil construction projects, particularly in road construction and maintenance, railways, airfields, retaining structures, reservoirs, canals, dams, erosion control, and landfill engineering. They play a critical role by improving soil strength at a lower cost than traditional methods and are pivotal in ensuring the longevity and sustainability of the engineered structures.