Development of an Innovative Uniaxial Compression Test to Evaluate Permanent Deformation of Asphalt Mixtures

Abstract

An innovative uniaxial compression test, capable of simulating the confinement and temperature condition in actual pavement, was developed in this study to evaluate the deformation of asphalt mixtures. Small-diameter loading head was utilized to create a confinement inside the specimen, which is similar to that in the field. Optimized loading head size was determined to provide the best confining effect. To reproduce the actual pavement temperature distribution in the tested specimen, a finite-element method (FEM) model was first developed to predict temperature at different depths of a pavement. Then, the laboratory temperature control system was calibrated by monitoring the temperature inside a dummy specimen to ensure the temperatures at different depths of the specimen are the same as in the pavement. Cylindrical specimens with different composition of mixtures were prepared for the uniaxial test to evaluate the deformation of the typical pavement structure at various temperatures, vehicle speeds, and load levels. The developed test method clearly differentiated different materials and reflected the influence of temperature, load time, and level. Test results showed high temperature increased the permanent stain. When the highest ambient temperature level was higher than 28°C, the test effectively differentiated different types of materials. In addition, low vehicle speed and overload significantly increased rutting potential of pavement.