The specimen is clamped in a ring about 150 mm across, and a flat-ended plunger 50 mm in diameter is driven through it while force is recorded. The name comes from the California Bearing Ratio equipment it borrows. It gives far less scatter than the small-pin puncture test and is the standard puncture index for cushion fabrics over geomembranes.
Cushion fabric needs 2,000 newtons CBR puncture minimum, so the 6-ounce won't cut it under that rock.
Also heard as
- static puncture
- CBR puncture strength
- plunger puncture
Related terms
Survivability
A geosynthetic's ability to make it through shipping, placement and compaction without being damaged.
Nonwoven geotextile
Geotextile made by needlepunching or heat-bonding fibers into a felt-like sheet, used for filtration, drainage and cushioning.
Grab tensile
Index tensile test on geotextiles in which a 100 mm wide specimen is gripped by 25 mm jaws in its middle.