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D1369-19 – Standard Test Method Technical Guide
ASTM D1369-19 provides a standardized practice for determining the quantities of asphalt materials and aggregates required for constructing high-quality asphalt-aggregate surface treatments. This practice applies to both single and multiple surface treatments applied over prepared pavements or bases. The standard serves as a critical reference for engineers and contractors to ensure optimal material application rates and pavement performance.
📋 Scope and Applicability
This practice covers the rates of application of asphalt materials and aggregates, as well as the types and grades of asphalt materials suitable for surface treatments. It applies to pavements or bases that have been suitably prepared to receive such treatments. The standard explicitly states that the values provided in SI units and inch-pound units must be regarded separately, as they are not exact equivalents. Combining values from the two systems may lead to nonconformance with the standard’s requirements.
⚠️ Important Note on Units: All values within this standard are provided in both SI and inch-pound units. These systems must be used independently. Do not combine measurements from different unit systems to avoid nonconformance.
🪨 Material Specifications and Aggregate Sizing
A successful surface treatment relies on the correct selection of materials. ASTM D1369-19 references a suite of companion standards to guide the specification of aggregates and asphalt binders. The table below summarizes the key associated standards for materials used in these treatments.
| 🛠️ Material Type | 📜 Referenced Standard |
|---|---|
| Aggregate for Surface Treatments | D1139/D1139M |
| Classification of Aggregate Sizes | D448 |
| Bulk Density and Voids in Aggregate | C29/C29M |
| Penetration-Graded Asphalt Binder | D946/D946M |
| Emulsified Asphalt | D977 |
| Cationic Emulsified Asphalt | D2397/D2397M |
| Cutback Asphalt (Rapid-Curing) | D2028/D2028M |
| Cutback Asphalt (Medium-Curing) | D2027/D2027M |
🏗️ Treatment Types and Construction Guidelines
ASTM D1369-19 formally defines two primary types of surface treatments: single-surface and multiple-surface. A single-surface treatment consists of a single layer of aggregate placed over an initial application of asphalt material. A multiple-surface treatment begins with coarser aggregate placed over the initial asphalt, followed by one or more subsequent applications of asphalt and smaller aggregate. The standard provides a key geometric rule for these subsequent layers, ensuring mechanical stability of the pavement.
💡 Design Rule for Multiple Treatments: In a multiple-surface treatment, the designated maximum size of the aggregate used in each subsequent layer should generally be one half the nominal maximum size of the aggregate used in the immediately preceding application.
The following table summarizes the definitions of these treatment types as established in the standard’s terminology section.
| 🏷️ Term | 📖 Definition |
|---|---|
| Single-Surface Treatment | A wearing surface of asphalt material and aggregate in which the aggregate is placed uniformly over the applied asphalt material in a single layer. |
| Multiple-Surface Treatment | A wearing surface composed of asphalt material and aggregate, in which coarser aggregate is placed uniformly over an initial application of asphalt material and followed by one or more subsequent applications of asphalt material and smaller aggregate. |
❓ Frequently Asked Questions
🔍 What is the scope of ASTM D1369-19?
ASTM D1369-19 covers the rates of application of asphalt materials and aggregates, as well as the suitable types and grades of asphalt materials for single and multiple asphalt surface treatments applied to prepared pavements or bases.
💡 What defines a multiple-surface treatment?
A multiple-surface treatment is a wearing surface where an initial layer of coarse aggregate is placed over asphalt, followed by one or more subsequent applications of asphalt and progressively smaller aggregate.
⚡ Why are SI and inch-pound units treated separately in this standard?
The standard states that the values in each system may not be exact equivalents. Therefore, each system must be used independently of the other to avoid nonconformance with the specified material quantities.
📌 How is aggregate size selected for subsequent layers in a multiple treatment?
Per the standard, the designated maximum size of the smaller aggregate in a subsequent application is generally one half that of the aggregate used in the preceding application.