Geosynthetic materials are used in a wide variety of applications within civil engineering, most often to provide strength to unstable surfaces. One use of geosynthetics is debris capture, for example on construction sites where explosives are being used or in cities where construction debris must be contained.
Geotextiles and geosynthetics are essentially composite sheets made up of a mixture of traditional textiles as well as both oil- and bio-based plastics.
ISO 10319 is a test method for determining the tensile properties of geosynthetic materials using 200 mm wide strips. The strength of these materials combined with the geometry of the specimen can prove difficult to grip with traditional methods. Instron’s solution is capstan-style grips that prevent jaw breaks and slippage.
Traditional contacting extensometry has always been difficult with textiles of any sort, and geotextiles are no different. In fact, due to the difficulties of contacting extensometers, many companies testing these materials simply rely on crosshead displacement for strain measurement. This method is less accurate than a dedicated strain measurement device.
Instron has a non-contacting solution that addresses this problem. The AVE 2 and SVE 2 optical extensometers measure elongation by tracking marks on the specimen. This method avoids any mechanical influence on strain data which can be an issue when using contacting extensometry.
The challenges of testing to this standard are:
- Specimen gripping
- Instron’s non-contacting AVE 2 optical extensometer is well-suited for measuring strain on geosynthetic specimens without mechanically influencing the results
- Capstan grips allow for proper specimen gripping while eliminating slippage and jaw breaks, and are available in capacities up to 50 kN
It is important to review ISO 10319:2015 in order to fully understand the test setup, procedure, and results requirements.