Investigating the Relationship between the Optimal Bitumen Amount of Warm Asphalt Mixture and the Technical Characteristics of Stone Materials (Case Study)

One of the important parameters in the asphalt mixture from the economic and technical point of view is the amount of bitumen consumption. On the other hand, the performance of asphalt concrete as one of the road pavement layers is strongly influenced by the quality of aggregates. Stone materials are one of the most important components of asphalt and concrete pavements, which include about 75 to 85% of the volume of hot asphalt. Physical, chemical and mechanical properties of these materials play an important role in pavement performance. In this article, the effect of ductility percentage, true specific weight of stone material mixture and sand value on the optimal bitumen content of hot binder asphalt mixture (0-19) mm from 8 selected mines in 8 different projects in Kerman Province. By comparing the results and analysis of stone materials tests, the optimal amount of bitumen in the asphalt mixture of each project it turned out.
The relationship between the changes in the actual specific gravity of the mixture of stone materials and sand with changes in the amount of optimal bitumen has a reverse ratio, and the relationship between the changes in the ductility percentage of stone materials and the changes in the amount of optimal bitumen has a direct relationship.  So it was observed that with a change of 0.01 g/cm3 in the specific weight of the stone material mixture, 3% in the equivalent of value sand and 2.49% in the ductility stone materials, 0.1% change in the amount of optimal bitumen is created. Therefore, using the results of this research, it can be concluded that in order to reduce the amount of bitumen consumed in hot asphalt mix, high density stone materials and low ductility percentage and higher sand value can be used.