Puncture index test

Puncture resistance (puncture index test) ASTM D4833 Replaced by CBR test ... 

In the past, the puncture index test was also used for GTX. This test is similar to the static puncture test (CBR) but a different plunger (0 8 mm) is used and the specimen is smaller. CBR tests have replaced the puncture index test because the CBR test gives more consistent results than the small puncture index test. 

The method described by Hirsch et al. (H4) uses intact male rats previously maintained on a low-calcium diet for 4 days. Standard and unknown preparations are injected subcutaneously into parallel groups of test animals, and after 1 hour blood samples are collected by cardiac puncture under ether anesthesia. The plasma calcium levels are measured, and the relative potencies of the preparations are calculated by standard statistical procedures. The mean index of precision of ten consecutive assays was reported as 0.23 0.025. 

Gangstad and Snell (1943) have made detailed use of regression techniques in a study of the texture of sweet com. Three standard varieties, one experimental variety, and the parent inbreds were tested with a puncture meter to measure resistance (in grams) in relation to dry weight and maturity (days after pollination). Dry weight is a reliable index of maturity for sweet com, and on this basis it was postulated that puncture resistance should be a valid measure of some function of dry weight and days after pollination (maturity). 

ASTM D4833 2000 Standard Test Method for Index Puncture Resistance of Geotextiles, Geomembranes, and Related Prodncts... 

Figure 17.4 Typical setup for an index puncture test.

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