Assessing rutting susceptibility of five different modified asphalts in bituminous mixtures using rheology and wheel tracking test

Rutting is one of the most important distresses in asphalt pavements due to its frequency. Rutting or channeling, could be classified in three types: 1) mechanical deformation (rutting in subgrade or base), 2) plastic flow (unstable asphalt layer), and 3) wheel path consolidation. The plastic flow of bituminous mixture depends on many factors; one of this is the type of asphalt used in the mixture. Actually, rheology studies are used for asphalt analysis and to predict rutting susceptibility in bituminous mixtures. With the rheology analysis; it could be possible to predict the maximum temperature at which asphalt works properly as a bituminous mixture constituent. In other words, the high temperature at which asphalt does not increase mixture susceptibility to rutting via plastic flow. In this article, the authors describe the work done to analyze the susceptibility of different modified and unmodified asphalts using four different rheology methods. Also they analyze the resistance to rutting of bituminous mixtures (made with the same asphalts), at different temperatures using the Spanish Wheel tracking device. The main objectives were to verify if rheology analysis could be related to bituminous mixture resistance to rutting and to find differences between the four rheology methods used in this investigation. Bituminous mixtures were made according to Mexican specifications. The wheel tracking device was constructed and performs according Spanish standard NLT-173.