Typical Pavement Structure Optimization in Eastern Inner Mongolia Using a Combined Weight-Fuzzy Approach

The properties and service life of asphalt pavement are to a large extent dependent on pavement structure. Most pavement structural designs at home and abroad commonly follow the typical structural design method; however, considering that the geographical span from east to west in Inner Mongolia is large, a single pavement structure cannot be optimal for all environments, and low-temperature fracturing may easily occur during the road service life. Ten kinds of pavement structures are analyzed in this paper. The pavement structure mechanical indices are analyzed using different soil base modulus values, different axle loads, and different internal contact conditions. A low-temperature return period was introduced to establish a Gumbel extreme temperature model. The low-temperature protection index and calculation method based on the return period for asphalt pavement is proposed, which takes Arxan City as a benchmark for calculating low-temperature protection values in Eastern Inner Mongolia. The low-temperature fracturing formula is improved to calculate low-temperature indexes for different pavement structures. Using a life cycle cost model, the economy of different pavement structures is evaluated from the aspects of initial cost, maintenance cost, and pavement residual value. By establishing a combined weight-fuzzy pavement evaluation model and combining the mechanical response, low-temperature fractures during the return period, and economy of the life cycle, a comprehensive property ranking for different pavement structures was obtained. Finally, the typical structural combination for the asphalt pavement in the Eastern Inner Mongolia is recommended to be three layers of asphalt surface + semi-rigid base or three layers of asphalt surface + asphalt treated base (ATB) + semi-rigid base.