Investigation of the Temperature-Dependent Precompaction and Flow Behavior of Hot Mix Asphalt

Abstract

The flow behavior and precompaction resistance were investigated for the first time as part of this study. New laboratory methods were developed and applied for this purpose, some of which were based on already established methods. In order to evaluate the influence of temperature on the paving behavior of the asphalt paver, the flow behavior and precompaction resistance were investigated for three selected asphalt mixes (AC 11 DS, SMA 11 DS, AC 16 BS). The temperature was varied in three steps (130°C, 160°C, and 190°C). An extensive literature review of possible laboratory tests was conducted, which concluded that static compaction and the funnel fall test are suitable for investigating the corresponding properties of the asphalt mixes. The results showed that the bulk density of a loose fill asphalt mix is significantly dependent on temperature. Higher temperatures result in higher poured density due to the thermoviscosity of the bitumen, specifically, the viscous τ_visc and cohesive τ_c resistance components. Considering the performed laboratory tests, this phenomenon results in the loose fill of all tested asphalt mixes having a lower precompaction resistance at lower temperatures. In addition, the influence of temperature on the flow behavior and thus the internal friction of the asphalt mixes was demonstrated. Higher test temperatures resulted in a substantial reduction in flow time up to 225% and thus significantly improved flow behavior.