The use of geotextiles in the construction industry includes many varied applications. They are used particularly for separating, filtering, drainage and protection purposes and, because of their good tensile and stretching properties, they are ideal for layers between different construction materials and soil.
In projects such as earth movement, landscaping and transport infrastructure they are replacing traditional materials such as woven or knitted fabrics. The materials are subject to compressive forces from stones, rocks etc., and these forces are increasing due to poor quality of filling materials, compaction during the construction process, or the weak load bearing capacity of the underlying base material.
Test Methods / Standards
The determination of the puncture resistance of geotextile materials is carried out by the CBR static puncture test according to EN ISO 12236 or ASTM D6241. The CBR test is an empirical test first developed in California (USA), for estimating the bearing value of highway sub-bases and subgrades. The test is normally carried out with a dry specimen under controlled climatic conditions specified by ISO 554. If required, tests can be also carried out with a wet specimen.
Range of solutions within the Zwick Roell group
Zwick offers two types of tooling which ensures that most geotextile materials can be tested in full compliance with the standard.
Using a testing system with hydraulically operated clamping tools enables all geotextiles classified within the robustness classes (GRC) 1...5 can be tested. This is the ideal solution for organisations performing large number of tests. The system is easy to use with single button operation and reduces operator fatigue.
For geotextiles within robustness classes 1...4, a manually operated mechanical test device can be used. This version also ensures standard compliant testing but is lower in cost.
The materials testing software testXpert II is fully configured for the CBR test, and guarantees full control of the test procedure and automatic determination of all results. In addition, the test program can determine penetration forces at pre-determined distances. Manual operations are minimised for the user, and test data can easily be exported to Microsoft Office for additional reporting, processing. A flexible and modular-built range of tools and fixtures is available for additional test requirements.