Effects of Mix Design Variables on Mechanical Properties of Hot Mix Asphalt

Abstract

Compaction of hot mix asphalt after the laydown process is one of the critical steps of construction affecting the service performance of asphalt concrete. It is known that compaction is controlled by a number of mix design variables, i.e., binder type, gradation, asphalt content, and compaction temperature. In this paper, effects of mix design variables on the mechanical properties of hot mix asphalt are investigated based on laboratory compacted specimens. A continuum model is utilized to simulate the laboratory compaction using the Superpave gyratory compactor. The mechanical properties are estimated by fitting the model to laboratory compaction curves using a parameter estimation algorithm. Statistical analysis of variance was conducted to identify the significant design variables affecting the mechanical properties. It was found that gradation and asphalt content are the most influential mix design variables for the mechanical properties during compaction. Results also indicted that binder type is a statistically more significant variable for the mechanical properties than compaction temperature as indicted by the outcome of analyses.