Dynamic Modulus and Rutting Performance of As-Built Hot-Mix Asphalt Using Small-Scale Specimens

Abstract

The dynamic modulus of asphalt concrete (AC) mixtures is commonly measured using cylindrical specimens having a 100-mm diameter and a 150-mm height (full-size specimens). Testing as-built AC mixtures using this geometry is rarely possible because the required specimen height is greater than the typical AC lift thickness. In this study, the feasibility of using small-scale cylindrical specimens to measure the dynamic modulus of AC mixtures was investigated. Dynamic modulus tests were conducted on full-size and two small-scale (common height of 110 mm and two diameters of 38 and 50 mm) geometries extracted from gyratory-compacted samples. Both small geometries showed similar performances to full-size specimens except at high temperature of 37.8°C, where they resulted in greater dynamic modulus values. Second, field cores were collected from highways to perform the dynamic modulus and Hamburg wheel tracker tests, and the two test results were correlated. The findings showed that small-scale specimens are capable of measuring the as-built dynamic modulus of AC mixtures and predicting their rutting performance in the laboratory.