1. Scope

Keywords

Rationale

For many years, material specifications have been adopted for geotextile fabrics used to build sediment barriers. It is widely accepted these material specifications establish index properties for the fabric, yet do not correlate to better performance as a sediment barrier in full scale testing or case studies. ASTM D6461, Standard Specifications for Silt Fence Materials, contains minimum material specifications for “commodity” silt fence fabrics based on AASHTO M288. D6461 also contains a material specification for higher strength, higher flow geotextiles to be used in sensitive applications and areas prone to high flow that require increased structural stability and the ability to withstand increased hydraulic flows. Table 2 of D6461 provides for the use of geotextiles with higher grab tensile strength. However, it does not address a common failure point of fastener pull-through of the geotextile fabric at the point of attachment. Silt fence sediment barriers are only as strong as the weakest component of the system. If the interface between the fastener and fabric pulls-through at forces less than the force exerted by full impoundment of stormwater runoff on the system, failure will occur resulting in uncontrolled sediment discharge. This test method provides a consistent means of determining pull-through resistance at the point of attachment for fabrics attached to wood or steel structure using a consistent fastener. The method could also be expanded to test pre-assembled silt fence sediment barriers that are assembled using different types and numbers of fasteners to measure the overall strength of the system to include the post, fastener, and fastener pull-through strength. Data from these tests in conjunction with loads calculated based on impoundment height could be developed to establish specifications that correlate to actual field requirements of the practice