Investigation of using Coal Waste in asphalt mixtures and it's effects on moisture damage with the approach of bitumen chemistry and asphalt mixture mechanical test

Moisture damage is one of the main causes of many failures affecting the performance and durability of asphalt mixtures. This damage occurs with the entry of moisture (water) into the pavement layer and it intensifies other failures such as rutting and raveling in the asphalt mixture layers. Based on this, in this research, the impact of using different types of coal wastes (CW) as waste of its extraction process (Coal Jig and Coal Flotation Waste) on the performance of asphalt mixture, that's in facing the phenomenon of moisture damage has been investigated. After performing tests to identify the physical and chemical structure of CW, four different combinations of laboratory asphalt mixtures containing of CW were prepared. Coal Wastes in equal percentages were added to bitumen and surface free energy (SFE) and Fourier-transform infrared spectroscopy (FTIR) tests were performed on bitumen and the Indirect Tensile Strength (ITS) test was conducted on modified asphalt mixtures. The results of this study indicated that the use of Coal Jig Waste (CJW) compared to Coal Flotation Waste (CFW) increases the polar components of bitumen and increases adhesion as well. Also, the results obtained from the indirect tensile strength test indicated an improvement of resistance to moisture damage as a result of the using of Coal Jig Waste