Geotextiles are currently specified in many different ways. Engineers specify geotextiles by brand name, mass, type, and/or any mix of properties including strength, puncture resistance, "G" Rating, EOS, and hydraulic properties. However, in Australia, no unified method exists of specifying geotextiles in a simple manner. Some specifications are unnecessarily biased against certain types of geotextiles, particularly wovens. Each State road authority has its' own method. This causes unnecessary confusion and complexity to engineers, manufacturers and contractors alike. This paper presents a case for adopting a simple, unified method of specifying geotextiles. Current Australian specifications are reviewed against worlds best practice.
Geotextiles have been used in Australia for over 30 years, beginning with the introduction of Terram, or "Terra-Firma" as it was widely known, imported by ICI many years ago. The key development in the local industry throughout the 1980"s was the setting up of a local Bidim non-woven manufacturing facility at Albury by Geofabrics Australasia in July 1987.
In the late 1980's Standards Australia Committee CE/20 Geotextiles released the Draft Australian Standards for Geotextiles - series AS3706 which addressed general requirements, strength tests, hydraulic tests and durability tests. In 1990 Austroads published its' Guide to Geotextiles (Austroads 1990) which covered topics including Geotextiles Properties and Functions, Applications and Design, Durability, Construction and Testing. Due to lack of interest and funding there has been little further development work by Standards Australia or Austroads to standardize specifications for geotextiles. In Australia only the NSW RTA (Roads & Traffic Authority) has continued work in this area (RTA 1998 R63 Geotextiles, Separation and Filtration). In America AASHTO (the American Association of State Highway Transport Organisations) released its Standard Specification for Geotextiles M 288–96 (Ref.4) recently, which is widely recognised as worlds best practice.