The world has developed different methodologies for the design of asphalt mixtures; each of which is intended to optimise and find the optimal combination of materials that allow them to be resistant under specific travel, climate and structural support conditions. This article presents the results of an investigation which utilised coal tar as a binding agent for road surface mixtures and carried out a comparison of results of the physical and mechanical properties of sample bituminous mixtures produced by two distinct methodologies, Marshall and Ramcodes. Finally, an analysis was carried out on the suitability of tar as a binding agent and on utilising the Ramcodes methodology when designing mixtures.

Slag from a Blast Oxygen Furnace (BOF) is produced during the transformation of cast iron, coming from the blast furnace, into steel during the integrated steelmaking process, just as blast furnace dust (BFD) is produced during the transformation of the iron mineral into cast iron. These residues have generated environmental problems due to the accumulation and inadequate disposal thereof. Consequently, this study aims to analyze the use and behavior of the dynamic modulus and the fatigue in asphalt mixtures with partial (50 %) and total (100 %) substitution of the coarse aggregate for BOF slag and the fine aggregate for BFD. The results are compared with the behavior of a mixture elaborated with conventional aggregates. To achieve this objective, the chemical and physical properties of BOF and BFD were determined along with the optimum asphalt cement content, determined using the Ramcodes methodology. Tests were carried out to evaluate the physical characteristics, the dynamic modulus, and the fatigue of each type of mixture. The results of this study demonstrate adequate fatigue behavior and a slight reduction in dynamic modulus in mixtures with BOF and BFD. This allows us to deduce that the use of these residues is feasible and thereby to contribute to sustainable development and the protection of the environment.