GeoTesting Express is a provider of Geosynthetic Testing Services – ASTM D,Standard Test Method for Determining Apparent Opening Size of a Geotextile. Apparent Opening Size (ASTM D). • The ASTM method also called as the dry method. The ASTM method, also called as the dry method uses glass beads. The U.S.A adopted the Apparent Opening Size (AOS) method (Test Method ASTM D 99a) in This test method, although similar to.

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The Devil is in zstm Details The most common way this property is reported is: Laboratories electing the use of Method B must first determine any bias that exists between the two methods and document a reliable correlation in accordance with this test method.

AOS (ASTM D-4751) – A Straightforward Method a Confusing Result

Current estimates of precision, between laboratories, have been established. The test is carried out on a range of sizes of glass beads. Leave a Reply Cancel reply You must be logged in awtm post a comment.

While we believe this to be un-intentional, if interpreted as written, atm specification now requires a maximum bead size of.

Historical Version s – view previous versions of standard. If a bias is found, either its cause must be found and corrected or the purchaser and the supplier must agree to interpret future test results in the light of the known bias. Always resist the temptation to add the millimeter bead size if the specification only lists the Asstm Sieve number and vice-versa. SI units is the technically correct name for the system of metric units known as the International System of Units.


Or does he want a fabric with no larger than 60 Sieve number? Mesh or Sieve number and the correlating millimeter bead size. Geotextiles from different manufacturers or with different nominal unit weights are considered different products. The test specimens should then be randomly assigned in equal numbers to each laboratory for testing.

Competent statistical assistance is recommended for the investigation of bias.

How is one to know for sure? The values in inch-pound units are provided for information only. However, it is our belief that specifiers should list only the bead size to eliminate any doubt as to the intent of the specification.

Unfortunately, AOS is reported in a confusing manner. Thanks for reading our blog!

What is the intent here? You must be logged in to post a comment. Astmm correlation should be confirmed for a particular product by comparing a minimum of three test results when there are changes in 4d751 manufacturing of a specific pre-qualified geotextile.

A 40 Sieve has a corresponding bead size of. A minimum of three test results must be compared with all three satisfying the established correlation. As a minimum, the two parties should take a group of test specimens that are homogeneous as possible and that are from a lot of material of the type in question.

Leaving the intent of a specification to a geotextile company or contractor is certainly not what most specifiers have in mind.

ASTM D – 16 Standard Test Methods for Determining Apparent Opening Size of a Geotextile

For example, a 60 Sieve has a corresponding bead size of. The M specification does not include the bead size. During the test, spherical, solid glass beads are dry sieved through a geotextile for a specified time and at a specified frequency of vibration. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.


Inch-pound units is the technically correct name for the customary units used in the United States. In the case of the attached specification it should read: The most common way this property is reported is: The problem lies in the relationship atm the U.

Does the specifier want a fabric that will not pass any larger than a. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Link to Active D47511 link will always route to the current Active version of the standard.

The average results from the two laboratories should be compared using Students t -test for unpaired data and an acceptable probability level chosen by the two parties before the testing is begun.

This test method is used to indicate the apparent opening size in a geotextile, which reflects the approximate largest opening dimension available for d47751 to pass through. D7451 amount of beads retained by the geotextile sample is then measured. The Solution Always resist the temptation to add the millimeter bead size if the specification only lists the US Sieve number and vice-versa.

It is the intent of this test method to confirm the equivalency of the Method B results before permitting the use of this alternative.