Under what condition is the GMM dry back procedure considered complete?

The GMM (Gyratory Compactor Method) dry back procedure is considered complete when the weight loss is less than 0.5 grams. This criterion indicates that the sample has reached a state of equilibrium, where the moisture content has stabilized and any further drying would result in negligible weight loss. Achieving a weight loss of less than 0.5 grams ensures accurate determination of the moisture content, which is critical for the proper assessment of the asphalt mix properties. This stability indicates that the sample has been dried sufficiently without risking over-drying, which could unintentionally alter the material properties and affect the test results.