Modification of Hot Asphalt Mixtures in Jordan and Syria by Using Steel Slag

Roads in the Arab world face so many problems, especially at the surface of the pavement due to the variations in the weather conditions (high and low temperatures) and the design methods of the hot asphalt mixes. Therefore, we need to avoid any defect in the asphalt pavement surface such as fatigue and thermal cracking. The main objective of this study is to solve the problem of temperature variations in Syrian and Jordanian roads, by choosing the right type of asphalt binder that would be suitable to temperatures in a variety of areas, improving the design of hot asphalt mixtures in different areas according to temperature variations and selecting the right design method. To do this, the asphalt binder was classified according to temperature variations. A temperature map was prepared by dividing Syria and Jordan into temperature zones. Steel slag was used in the hot asphalt mixtures with different percentages (15, 30 and 45%) according to the total weight of coarse aggregates in the mix. Marshal, Superpave and a combination of the two design methods were used. Fatigue, indirect tensile strength, loss of indirect tensile strength and the resilient modulus laboratory tests were performed on all hot mixes. Tests results were studied and analyzed. It was found that using (30%) of the steel slag in the mixture was the most suitable manner. Using the Superpave mix design was best as it showed 20% more stability than the Marshall design method.