AASHTO T 346-22

The procedures for testing glass beads used in traffic markings are described in this method. This includes the method for obtaining a representative test sample, preparation of the test specimens, and performing the specified tests.

This test method is divided into the following parts:

• Sampling Glass Beads During Production;
• Sampling Shipments of Glass Beads Vertically from Bulk Containers;
• Gradation;
• Roundness;
• Refractive Index;
• Flow Characteristics Test—Referee Method;
• Moisture Resistant Coating Test—Referee Method;
• Flotation Test—Referee Method;
• Adherence Coating Oven Test—Referee Method;
• Alternative Flotation Test—As Permitted by Purchasing Agency;
• Alternative Moisture Resistant Coating Test—As Permitted by Purchasing Agency; and
• Alternative Adherence Test—As Permitted by Purchasing Agency.

This standard was formerly designated as provisional standard TP 97.