IMPACT OF SUPERPAVE MIX DESIGN METHOD ON RUTTING BEHAVIOR OF FLEXIBLE PAVEMENTS IN PAKISTAN

Premature rutting of flexible pavements is one of the major pavement distresses being faced by this country. Pakistan has national highways with a length over 9555 km. and motorways of 515 km. Flexible pavements, with bituminous surfacing as a wearing course, are widely used in Pakistan. Superpave technology can be adopted for the design of flexible pavements in the country. The objective of this study was to compare the design of asphaltic concrete by the Superpave and Marshall methods of mix design. These were subjected to comprehensive laboratory testing after samples of both mixes were prepared at the design asphalt contents and aggregate gradations. These tests included: Indirect Tensile Strength, Creep Performance; and Moisture Sensitivity. The Superpave mix showed better results compared to the studied properties of asphalt. Guidelines for implementing the Superpave mix design procedure in Pakistan have been proposed. A performance grading map has also been proposed, to be implemented in Pakistan by dividing it into four zones according to the highest and lowest pavement temperatures