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From the GMA Techline
RE: Mullen Burst Test?
I have a project that requires the Mullen Burst Test (ASTM D3786) be performed on a geotextile that is described as a needle-punched, nonwoven geosynthetic fabric suitable for reinforcement applications. I have been told by a supplier that the Mullen Burst Test is no longer recognized by ASTM Committee D35 on Geosythetics as an acceptable geosynthetic test method and therefore they will not certify that their material meets the requirements of the project.
Do you have any insight as to why the test was removed? Furthermore, has the committee identified a replacement test for this property?
Your help is appreciated,
(Dan | Arizona)
Reply: Here is the “skinny” on your question. Mullen Burst (ASTM D3786) was indeed one of the index strength tests for geotextiles from the outset and for many years afterward. During that time period, however, it was recognized that lightweight nonwoven fabrics had a rather large statistical variation between small areas of somewhat dense fibers and other small areas with sparse fabrics. One can visually see the variations when holding the sample up to light.
This same issue holds for the pin puncture test (ASTM D4833), which is a 3/16-in. diameter probe. This was recognized by the relevant ASTM D35 committee and it decided to abandon (ASTM calls it “depreciate”) both tests in favor of the CBR puncture test (ASTM D6241).
This test configuration comes straight from geotechnical testing using a 2.0-in. probe in a 6.0-in. cylinder. With such a larger test specimen the standard deviation is significantly improved and is more representative of the fabric under investigation.
AASHTO, in its M288 specification, has accepted the changes.
In my opinion, there is one other significant advantage of using the CBR test: its strength and elongation relationships to the wide-width tensile test (ASTM D4595). The CBR’s axisymmetric configuration is analytically related to the plane strain configuration of the wide-width test. Furthermore, it is much easier to accomplish.
I’ll send the equations if you want them,