Ruggedness and Interlaboratory Studies for Asphalt Mixture Performance Tester (AMPT) Cyclic Fatigue Test: Phase I Report

This report highlights findings from Phase I of a project designed to evaluate the ruggedness of the standards for cyclic fatigue testing using an Asphalt Mixture Performance Tester (AMPT). These standards include AASHTO TP 107-18 and 133-19, which are applicable to 100-mm diameter and 38-mm diameter test specimens, respectively. The ruggedness evaluation conducted adheres to the requirements of ASTM E1169-14 and integrates ASTM C1067-12 recommendations, which are specifically for construction materials. The experimental factors evaluated included air-void content, specimen height, diameter difference between loading platen and specimen, loading-platen parallelism, rest period between the dynamic modulus fingerprint and cyclic fatigue test, strain level, and temperature. Based on the outcomes of this experiment and several supplementary studies, changes to the AASHTO TP 107-18 and TP 133-19 protocols were proposed. The full report is available from the US Federal Highway Administration at https://www.fhwa.dot.gov/publications/research/infrastructure/pavements/21057/21057.pdf