Carbon black is added to many polymers to provide long-term resistance to ultraviolet-induced degradation. To achieve this, carbon black should be dispersed uniformly throughout the as-manufactured geosynthetic material. This test method is used to evaluate the uniformity of carbon black dispersion.

This test method is suitable only for those geosynthetics that can be sampled using a rotary or sledge microtome. The geometry, stiffness (hardness), or elasticity of some geosynthetic products precludes their being sampled with a micro-tome. The cross-sectional area of the geosynthetic must be composed of a continuous solid polyolefin material to be sampled using a microtome.

Extruded and oriented geogrids will require that microtome specimens be cut from the nonoriented bars of uniaxial products and the non-oriented nodes of biaxial products.

1.1 This test method covers equipment, specimen preparation techniques, and procedures for evaluating the dispersion of carbon black in polyolefin geosynthetics containing less than 5 % carbon black by weight.

1.2 This test method allows for a qualitative evaluation of carbon black agglomerates and other inclusions in polyolefin geosynthetics. This evaluation is based on carbon black dispersion size calculated area within microscopic fields of view.

1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. 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.

Note 1—This test method is for the evaluation of carbon black dispersion. This test method does not support or evaluate the distribution of carbon black.