Aggregate Gradation Influence on Grouting Results and Mix Design of Asphalt Mixture Skeleton for Semi-Flexible Pavement

Abstract

Abstract In this study, to design a satisfactory asphalt mixture skeleton for semi-flexible pavement (SFP), the effects of aggregate gradation on grouting results of porous asphalt mixture were analyzed based on the test results of 22 aggregate gradations. Moreover, the mix design method of asphalt mixture skeleton was also discussed. Results indicated that the grouting effects of asphalt mixture skeleton were affected by its internal void interconnectivity, including the morphological characteristics, structure, and size of pores, instead of the initial void volume (VV). The grouting effects of asphalt mixture skeleton were influenced by the fine aggregate at the specific particle size levels. An increase in the mixing proportion of coarse aggregates could improve the grouting effects. A valid mix design approach was developed to prepare the asphalt mixture skeleton of SFP. Finally, engineering properties of the grouted mixture specimens were validated. It was concluded that the aggregation gradation design was a very important aspect in effecting the grouting results of an asphalt mixture skeleton. Furthermore, the aggregate gradation should be selected to facilitate the cement slurry to permeate in full thickness of the asphalt mixture skeleton layer. This could be used to direct the design of asphalt mixture skeleton toward lessening field failures on the SFP.