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D4123-82 – Standard Test Method Technical Guide
📐 Test Overview and Scope
The D4123-82 standard covers the repeated-load indirect tension test for determining resilient modulus of bituminous mixtures. It applies to laboratory-fabricated or field-recovered cores. The test applies compressive loads vertically in the diametral plane of cylindrical specimens, measures horizontal deformation, and calculates resilient modulus using Poisson’s ratio. Recommended temperatures are 41°F (5°C), 77°F (25°C), and 104°F (40°C) with loading frequencies at 0.33, 0.5, and 1.0 Hz, yielding nine test values per specimen for comprehensive evaluation.
⚙️ Test Procedure and Key Parameters
The apparatus requires a testing machine capable of applying load pulses over a range of frequencies, durations, and levels. An electrohydraulic system with a function generator is typical. The load is applied with a haversine or suitable waveform. Deformations are measured, and resilient modulus is calculated from recoverable horizontal deformation. Two moduli can be derived: instantaneous resilient modulus from immediate recovery during unloading, and total resilient modulus from total recoverable deformation including time-dependent effects.
📊 Key Measured Properties
Resilient modulus values are used for material quality evaluation and as input for pavement design or analysis. The test can assess effects of temperature, loading rate, and rest periods. It is nondestructive, allowing repeated tests on the same specimen for conditioning studies. This method is not intended for specifications.
| 🟦 Temperature | 📏 Frequency (Hz) | ⚡ Waveform |
|---|---|---|
| 41°F (5°C) | 0.33, 0.5, 1.0 | Haversine or suitable |
| 77°F (25°C) | 0.33, 0.5, 1.0 | Haversine or suitable |
| 104°F (40°C) | 0.33, 0.5, 1.0 | Haversine or suitable |
💡 Tip: Ambient laboratory temperature may be substituted as appropriate, but the recommended series provides a thorough analysis of resilient behavior per Note 1 of the standard.
⚠️ Note: Users must establish appropriate safety practices, as the standard does not address all safety concerns.
❓ Frequently Asked Questions
🔍 What is the scope of D4123-82?
It covers procedures for preparing and testing bituminous mixtures to determine resilient modulus using the repeated-load indirect tension test.
💡 What test conditions are recommended?
Testing at 41°F (5°C), 77°F (25°C), and 104°F (40°C) with loading frequencies of 0.33, 0.5, and 1.0 Hz.
⚡ What moduli can be calculated?
Both instantaneous and total resilient modulus can be calculated from the deformation data.
📌 Can the test be repeated on the same specimen?
Yes, since it is nondestructive, tests can be repeated to evaluate conditioning effects like temperature or moisture.