Influence of the Shear Process on the Compaction Success and Friction Behavior During Asphalt Paving

As part of this research, the shear process during asphalt paving with the paver screed was investigated in the laboratory. An extensive international literature search revealed that the influence of the shear process on the compaction success during asphalt paving has not been investigated to date. In addition, only limited data on the coefficient of friction between the asphalt mix and the screed plate exist from in-situ measurements. The investigations in the laboratory were carried out with a customized frame shear device of the Institute of Geotechnics at the Technical University of Darmstadt. The asphalt mix types AC 11 DS, SMA 11 DS and AC 16 BS (according to the German guideline TL Asphalt-StB) were used for this purpose. In addition, the influence of temperature changes and grading curve changes was investigated using the AC 11 DS asphalt mix. On the basis of the results, it was possible to prove for the first time that a significant increase in density takes place as a result of the shear process under constant normal stress. Where the influence on the compaction success depends on the asphalt composition. In addition, in-situ measurements could be validated based on determined sliding friction coefficients. The friction coefficients showed a material and temperature-dependent behavior.