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D3423 – Standard Test Method Technical Guide
The ASTM D3423/D3423M standard covers the application of mineral-colloid-stabilized emulsified coal-tar pitch (Specification D5727/D5727M) as a weather protection and aliphatic-solvent-resistant sealer on bituminous pavements for airports, parking lots, and driveways. Values in SI or inch-pound units are to be used independently.
📋 Scope and Referenced Documents
This practice is intended for use with emulsified coal-tar pitch specified under ASTM D5727/D5727M. It provides guidelines for application to ensure weather protection and resistance to aliphatic solvents. The standard specifies that units in different systems are not exact equivalents and must be used independently.
🛠️ Surface Preparation and Cleaning
Proper surface preparation is essential. For weathered asphalt surfaces, the following steps are recommended:
| 🟦 Defect Type | 📏 Specification | 🎯 Treatment |
|---|---|---|
| Hairline cracks | Not specified | Ignore |
| Minor cracks | Less than 12.7 mm (½ in.) | Open to 12.7 mm depth/width; fill with approved crack filler |
| Oil/grease (non-penetrated) | Water-break-free after cleaning | Scrub with detergent; flush with clear water |
| Oil/grease (penetrated) | Widespread | Remove and patch; cold patch after 90 days for solvent-based materials |
Remove loose dust, dirt, and debris by sweeping or water flushing before application. Prime coats are needed for oxidized surfaces or traffic lines.
⚠️ Important: Do not use solvents for oil/grease removal; they may affect sealer adhesion. Use detergent and water instead.
⚙️ Application Considerations and Safety
The standard does not address all safety concerns; users must follow relevant health and environmental regulations. Ensure solvent-containing repairs are done at least 90 days before sealing to allow solvent escape.
💡 Technical Note: For oxidized surfaces, apply a prime coat after removing loose aggregate and let it dry completely before sealing.
❓ Frequently Asked Questions
🔍 What is the purpose of this practice?
To provide guidelines for applying emulsified coal-tar pitch as a protective sealer on bituminous pavements for weather and solvent resistance.
💡 How should old surfaces be prepared?
Repair defects, clean debris, remove oil/grease, and treat cracks as per specified procedures.
⚡ What are crack treatment requirements?
Minor cracks (<12.7 mm) must be opened to 12.7 mm depth and width and filled. Hairline cracks can be ignored.
📌 Why avoid solvents for oil removal?
Solvents can compromise sealer adhesion. Use detergent scrubbing followed by water rinsing.