Evaluation of asphalt mixtures modified with hydrated lime

Abstract

The bituminous aggregate must fulfill a set of basic technical requirements to achieve good durability for the flexible pavement, from sufficient bearing capacity for the loads expected to pass through, stability and good resistance to deformations resulting from the passage of loads at high temperatures, and securing an impermeable surface that achieves good water drainage. Where the importance of this research focuses on increasing the durability of asphalt mixtures by adding hydrated lime, and producing mixtures with high efficiency and resistance to moisture and various weather factors.The aim of this research is to study the effect of using hydrated lime as a partial replacement ratio of mineral filler on the mechanical characteristics of hot asphalt mixtures and their sensitivity to moisture.In this research, mineral aggregates had brought from Al-Salima quarries near Damascus, where the particles of aggregates larger than 19 mm had rejected. Bituminous binder had brought from Banyas refinery in Tartous governorate.Two types of hot mix asphalt had been designed: a traditunal mixture (consisting of mineral aggregates and a bituminous binder), and a modified mixture with hydrated lime (consisting of mineral aggregates with an optimum partial replacement ratio of hydrated lime powder with a bituminous binder), where 3 proportions had initially studied. Partial replacement of hydrated lime powder (1-2-3) % by the weight of the aggregates, to determine the optimum ratio to be used in the modified mixture.The Marshall was used to determine the ratio of bituminous binder, where the results of experiments on reference mixtures showed that the ratio was 5.85%, and it was also found that the ratio for adding hydrated lime was 2% of the weight of the aggregates, and that this ratio did not significantly affect the ratio of the bituminous binder in the mixture. It has been also found that the modified mixture with hydrated lime had improved its characteristics in terms of stability, flow and Marshall stiffness with the following percentages, respectively: 26%, 30%, and 80%, and it also improved resistance to moisture damage.