ASTM D4632 / D4632M - 15a

Standard Test Method for Grab Breaking Load and Elongation of Geotextiles

This grab test is used for geotextile fabrics to determine the breaking load (grab strength) and elongation (grab elongation). The grab test is a tensile test where the central part of the specimen's width is tested in the grips, which establishes the “effective strength” of the fabric. The effective strength is the strength of the material in a specific width, together with the additional strength contributed by adjacent material.

The specimen sizes are cut to 101.6 mm x 203.2 mm (4 in x 8in), with attention to the fabrication machine direction. The longer dimension in the machine direction is not the same as the machine cross-direction. The specimen is loaded onto the grips leaving a 75 mm (3 in) separation between the jaw faces. The pull test speed requirement is 300 mm/min (12 in/min). The required test results are the breaking load and apparent elongation.

    

We suggest using pneumatic side action grips that provides ease of use, productivity, and enhanced repeatability. Pneumatic action grips allow the user to set a clamping pressure, while manually operated grips depend on the operator's strength (which may not be so repeatable). This grab specifies 25.4 mm x 50.8 mm (1 in x 2 in) jaw faces with the longer dimension being parallel to the direction of the load. The opposing jaw face has to be at least as big and the combination must correspond in the second grip.

Refer product electronic Universal testing machine, test fixture vise grips.