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D4404-18 – Standard Test Method Technical Guide
ASTM D4404-18 standardizes the measurement of pore volume and pore volume distribution in soil and rock via mercury intrusion porosimetry (MIP). This method is fundamental for characterizing geological porosity by forcing mercury into a specimen under controlled, increasing pressure.
📐 Scope and Applicable Pore Size Range
This test method is specific to measuring pores open to the exterior of a soil or rock fragment. It cannot assess the volume of pores entirely enclosed by surrounding solids. The pore diameter range is strictly dictated by the instrument’s operating pressure, typically spanning from 400 µm down to 2.5 nm (0.0025 µm). Larger pores require alternative methods.
| 🟦 Parameter | 📏 Specification / Range |
|---|---|
| 🎯 Apparent Pore Diameter Range | 400 µm to 2.5 nm |
| 🔬 Pore Type Measured | Open pores (intrudable by applied pressure) |
| ⚙️ Measurement Principle | Mercury Intrusion Porosimetry |
| 📐 Reporting Units | SI units (cgs reporting permitted) |
| 📊 Significant Digits | Per Practice D6026 guidelines |
⚠️ Critical Safety Warning: Mercury is a designated hazardous material by the EPA, causing central nervous system, kidney, and liver damage. Always consult the applicable Safety Data Sheet (SDS) and EPA guidelines before handling.
⚙️ Test Procedure and Core Principles
The procedure applies high pressure to force non-wetting mercury into the sample pores. The volume intruded at each pressure step provides the cumulative pore volume and distribution.
The standard explicitly warns that high pressure may cause a temporary or permanent alteration of pore geometry. Although soils and rocks are relatively strong, the possibility remains that this test method could alter the natural distribution being measured.
⚡ Potential for Sample Alteration: High pressure application during testing can alter the microstructural pore geometry. This test method may compromise the accuracy of the “natural” pore distribution measurement, particularly in fragile specimens.
📊 Data Reporting and Measured Properties
The primary outputs are cumulative intruded mercury volume and the derived pore volume distribution. All observed and calculated values must conform to the significant digits and rounding guidelines in Practice D6026. The reported volume is strictly limited to open pores intrudable within the instrument’s pressure range.
| 🟦 Property | 📐 Description |
|---|---|
| 🎯 Cumulative Pore Volume | Volume of mercury intruded at a specific pressure corresponding to an apparent pore diameter. |
| 📊 Pore Volume Distribution | Derivative function of incremental volume change relative to pore diameter or pressure. |
| ⚙️ Intrudable Pore Volume | Only includes open pores within the instrument’s specific operating pressure range. |
❓ Frequently Asked Questions
🔍 What is the primary purpose of ASTM D4404-18?
To determine the pore volume and pore volume distribution of soil and rock fragments using mercury intrusion porosimetry.
💡 What range of pore diameters can be measured?
Typically between apparent pore entrance diameters of about 400 µm and 2.5 nm (0.0025 µm).
© 2026 TNLab — This article is a technical interpretation for reference only. The original standard as published by ASTM International takes precedence.