Sedimentology of fluvial deposits composition of Sharbyan River as raw material for hot asphalt and its optimization using hydrated lime

The Sharbyan River is located in the Sharbyan Village, Sarab, East Azarbaijan province. This river alluvials are supplied from rock units belonging to Oligomiocene and Miocene, including conglomerate, sandy lime, limestone, marl and shale. These deposits are used as raw materials for producing hot asphalt in two asphalt plants that have been built in the vicinity of this river, and the produced asphalt is used mainly in the neighbor provinces that have rather cold climate. Combined analysis of the sediments indicate high level of silica, around 60 percent, for which the prepared asphalt is prone to stripping phenomenon in the cold seasons. During this process, the moisture penetration in aggregates and asphalt mixtures, cause weakening bitumen - asphalt materials bounding and finally asphalt demolition. This study is based on conventional sedimentology methods, different standards of ASTM, AASHTO and Roads and Urban Development Ministry. In this study, the combined effects of hydrated lime (lime filler) and natural filter materials with different proportions was used to deal with the stripping phenomenon, and the parameters of strength, softness, indirect tensile strength have been appraised, as a criteria for evaluating the quality and durability of asphalt due to stripping process. The results show that, the mentioned parameters are affective and improved by these additives in various proportions. Therefore, the produced asphalt will have better quality and durability than previous methods without these additives. The results illustrate, with 3% lime, as the maximum ratio, stripping has the best score of 1, and is disappeared with improvement of other parameters.