Geotextiles are permeable textile fabrics used in engineering applications.
This report is a review of geotextiles and their uses in pavements of both sealed and unsealed roads. Also reviewed is the use of geotextiles for filtration and sub-surface drainage.
Most of the readily available geotextiles are of either woven or non-woven construction using synthetic fibres. The types of synthetic geotextiles and their generalised porperties are described. Specific properties are given for the geotextiles currently available in New Zealand. The test methods used to measure a geotextile's general, mechanical, hydraulic and durability properties are commented on.
The four main functions a geotextile can perform are separation, filtration, reinforcement and drainage. The function or funtions a geotextile performs in any specific application depends both on the situation and on the geotextile. Understanding of the function(s) performed in each of the many situations covered is essential for proper geotextile selection and usage.
The uses of geotextiles in pavements of both sealed and unsealed permanent roads are discussed, as is the use of geotextiles in pavement construction, and in unsealed temporary roads.
Filtration is covered in some detail. Included is commentary on particle transportation and filtration in fine grained soils. Also included is filtration design to ensure selection of the appropriate geotextile properties in both cohesionless and cohesive soils.
Reflective cracking, its causes, and its reduction by the use of geotextiles under overlays on existing pavements are considered. Case histories of overseas pavement trials and the use of geotextiles in chip seals are also considered. Other uses for geotextiles include their use in embankments on weak foundations, under concrete block overlays, for MESL (membrane encapsulated soil layers), and in geocomposites for subsurface drainage.
Keywords: Geotextile, pavements, roads, separation, filtration, reinforcement, drainage, fibres, construction, reflective, cracking, chip seals