Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
D6128-22 – Standard Test Method Technical Guide
📐 Scope and Measured Properties
ASTM D6128-22, under the jurisdiction of Subcommittee D18.24 on Characterization and Handling of Powders and Bulk Solids, specifies the apparatus and procedures for measuring the cohesive strength of bulk solids. The test method measures strength during both continuous flow and after storage at rest. Additionally, measurements of internal friction, bulk density, and wall friction on various wall surfaces are included within the standard’s scope (Section 1.1).
The generated data serves as a foundation for designing storage bins and hoppers to prevent flow stoppages caused by arching and ratholing, and to establish the necessary slope and smoothness of hopper walls to achieve mass flow (Section 1.3).
⚠️ Critical Applicability Requirement: This standard explicitly requires the bulk solid to achieve a steady state condition within the travel limit of the shear cell. Materials that cannot meet this requirement, such as those consisting of highly elastic particles, may not be testable using this method (Section 1.2).
⚙️ Test Procedure and Key Parameters
The Jenike Shear Tester is utilized to subject a bulk solid sample to controlled normal and shear stresses. The procedure is designed to simulate the stress states experienced in a storage bin, allowing for the determination of critical flow properties. The standard dictates that all observed and calculated values must adhere to the significant digit and rounding guidelines established in Practice D6026 (Section 1.4).
| 🟦 Measured Parameter | 📏 Application in Bin & Hopper Design |
|---|---|
| Cohesive Strength | Calculating critical arching and ratholing dimensions for continuous flow and after storage at rest. |
| Internal Friction Angle | Assessing the bulk solid’s shear strength and flow properties during steady state flow. |
| Wall Friction Angle | Determining the required hopper wall slope and surface smoothness to promote mass flow and prevent stagnant regions. |
| Bulk Density | Providing data for the structural design of storage equipment and pressure calculations (Section 1.3). |
📊 Units, Data Recording, and Referenced Documents
The standard mandates that the values stated in SI units are to be regarded as standard. No other units of measure are included (Section 1.5). The standard closely integrates with several other ASTM standards to ensure comprehensive and accurate testing.
💡 Industry Standard Practice: The procedures for data collection and calculation outlined in D6128 are representative of the industry standard. The retention of significant digits must be considered carefully, but the standard does not specify the exact digits for material variation or specific design objectives, leaving that to the user’s engineering judgment (Section 1.4.1).
| 📐 Standard | 🎯 Role in D6128-22 Testing Program |
|---|---|
| D653 | Provides standardized terminology relating to soil, rock, and contained fluids for use in the test method. |
| D6026 | Establishes the practice for using significant digits and maintaining data records in geotechnical testing, to which D6128 conforms. |
| D2216 | Specifies the laboratory method for determining the water (moisture) content of the test specimen by mass. |
| E691 | Provides the practice for conducting interlaboratory studies to determine the precision of the test method. |
❓ Frequently Asked Questions
🔍 What is the most common use of the data generated by ASTM D6128-22?
The primary application is in the design of storage bins and hoppers to prevent flow problems. The data helps determine the