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D2172 – Standard Test Method Technical Guide
ASTM D2172/D2172M-24 defines standard test methods for the quantitative extraction of asphalt binder from asphalt mixtures and pavement samples. This testing is crucial for assessing mixture composition and ensuring material quality in construction. The aggregate recovered can be analyzed for particle size distribution using Test Method D5444.
📐 Test Method Scope and Units
The standard applies to quantitative determination of asphalt binder content in various mixtures, excluding those containing coal tar. Results are expressed in either SI units or inch-pound units, each system to be used independently. The standard incorporates references to recovery methods such as the Abson method (D1856) and rotary evaporator techniques (D5404/D5404M, D7906). Note that the age of the material can impact accuracy, with older samples typically showing lower binder content.
⚙️ Extraction Procedure and Solvent Selection
The extraction process involves dissolving the asphalt binder using appropriate solvents, with specific safety hazards addressed in Section 7. The standard does not recommend a single solvent but references Specifications like D6368 for vapor-degreasing solvents. It is essential to follow safety protocols and environmental regulations. The method is not suitable for mixtures containing coal tar.
📊 Data Reporting and Precision
The standard outlines precision and bias guidelines in accordance with Practice C670. Factors such as aggregate type and residual chlorides can influence results. For consistency, the test should be performed on fresh mixtures when possible. The obtained binder content is key for mixture verification and quality assurance.
| 🟦 Recovery Method | 📏 Associated Standard | 📐 Typical Use |
|---|---|---|
| Abson Method | D1856 | Recovery from solvent solutions |
| Rotary Evaporator | D5404/D5404M | Asphalt binder recovery |
| Toluene-Based Recovery | D7906 | Recovery using toluene solvent |
| 🟦 Parameter | 📏 Specification | 🎯 Remarks |
|---|---|---|
| Sample Type | Asphalt mixtures, pavement cores | Not for coal tar mixtures |
| Unit System | SI or inch-pound | Use separately, no mixing |
| Aggregate Analysis | Per D5444 | After extraction |
| Material Age | Fresh preferred | Older samples may yield lower content |
⚠️ Safety Note: Section 7 of the standard specifies hazards. Always use appropriate personal protective equipment and handle solvents in well-ventilated areas.
💡 Technical Note: For best accuracy, perform the extraction on mixtures immediately after preparation. Aged samples may show reduced binder content due to hardening or loss of volatiles.
❓ Frequently Asked Questions
🔍 What is the main purpose of ASTM D2172?
The standard is designed for quantitative determination of asphalt binder content in asphalt mixtures and pavement samples, aiding in mixture analysis and quality control.
💡 How does sample age affect test results?
As noted in the standard, older samples tend to yield slightly lower asphalt binder content. Best results are obtained from fresh mixtures.
⚡ What solvents are recommended for extraction?
The standard references various solvents, including those specified in D6368 for vapor-degreasing. However, specific solvent choice depends on the method and safety considerations.
📌 Is this test applicable to all asphalt mixtures?
The test is not appropriate for mixtures containing coal tar. It is intended for typical asphalt mixtures and pavement samples.