Work Item
ASTM WK92089
New Test Methods for Pull-Through Resistance of a Geotextile Fabric Used as Silt Fence
1. Scope
1.1 This test method determines the fastener pull-through resistance of a geotextile fabric used as a vertical permeable interceptor designed to remove suspended soil from overland, non-concentrated stormwater runoff.
1.2 This test method is intended to be a performance test conducted to replicate the force applied to a silt fence sediment barrier when impounded with the anticipated depth of sediment-laden stormwater runoff. The basic test focuses on pull-through resistance by using a rigid support post and common fastener for each support type. The larger scale test is intended to evaluate the overall system strength to include the post, fastener, and fabric pull-through strength.
Keywords
Permeability; Erosion Control
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
The title and scope are in draft form and are under development within this ASTM Committee.
Work Item Status
Date Initiated: 08-26-2024
Technical Contact: Keith Potter