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D4260-23 – Standard Test Method Technical Guide
📐 Practice Overview and Purpose
ASTM D4260-23 defines the standard practice for liquid and gelled acid etching of concrete. This technique is used to prepare concrete surfaces before applying coatings, ensuring optimum adhesion by altering the surface profile and removing contaminants like laitance, grease, and curing compounds. The practice is essential for service conditions requiring strong bond under immersion, temperature changes, or mechanical stress.
🛠️ Liquid Acid Etching Procedure
Method A outlines the liquid acid etching procedure, starting with pre-surface preparation. The following steps are critical for effective etching:
| 🟦 Step | 📏 Description |
|---|---|
| 1 | Cure new concrete per ACI-308 for adequate strength. |
| 2 | Remove grease, oil, and contaminants (Practice D4258). |
| 3 | Mechanically remove fins and projections. |
| 4 | Ensure no standing water exists on the surface. |
| 5 | Use abrasion (Practice D4259) if curing compounds resist acid. |
These preparations create a clean, roughened surface ready for coating.
⚠️ Safety and Hazard Considerations
Handling acids requires strict safety measures. Section 6 mandates compliance with federal, state, and local regulations for use and disposal. Users must establish safety and health practices. Referenced ASTM standards provide additional guidance.
| 📄 Designation | 🎯 Title |
|---|---|
| D4258 | Surface Cleaning Concrete for Coating |
| D4259 | Preparation of Concrete by Abrasion Prior to Coating |
| D4262 | pH of Chemically Cleaned or Etched Concrete Surfaces |
| D4263 | Indicating Moisture in Concrete by Plastic Sheet Method |
| D4541 | Pull-Off Strength of Coatings Using Portable Adhesion Testers |
📌 Use personal protective equipment and proper ventilation when working with acid solutions.
⚠️ Consult Practice D4258 for thorough cleaning to avoid coating failures.
❓ Frequently Asked Questions
🔍 What is the difference between liquid and gelled acid etching? Liquid acid is designed for horizontal surfaces, while gelled acid is intended for vertical and overhead surfaces to ensure adequate contact time.
💡 How should new concrete be prepared before etching? New concrete should be cured per ACI-308 guide to achieve sufficient strength and remove laitance.
⚡ What are the key safety considerations for acid etching? Follow federal, state, and local regulations; use appropriate safety equipment; and dispose of materials responsibly.
📌 Why is surface profiling important in acid etching? It enhances coating bond by creating a rough, clean surface free from contaminants and weak layers.