Comparative Evaluation For Mix Design of Marshall and Superpave Methods

Abstract

The SHRP conducted a $ 50 million research effort to develop a Superpave mix design as a new concept for the design of bituminous mixes. The main objective of the present research is the comparison between the design of Marshall and Superpave mixes if applied in the mix design of the wearing course layer in flexible pavements. Detailed experimental work is carried out to achieve the objectives of the study by preparing asphalt concrete Marshall and Superpave specimens to evaluate the volumetric properties for each mix design method. These specimens were tested by the Lottman test to evaluate the tensile strength value. The effect of additives and film thickness of asphalt on the performance of these mixes was also investigated. To compare two mixed design methods, the Marshall test was also investigated. From the analysis results, it is concluded that; the Superpave Gyratory compactor is capable of achieving air void contents much lower than that when using the Marshall hammer. it is also concluded that; the Superpave mixes are more economical as compared with traditional Marshall mixes. In addition, adding carbon fiber and lime to the mixes increases the tensile strength value