Seasonal effects of heavy axle loads on flexible pavement response.

摘要

The reduction of the subgrade strength during the spring thaw season is a major factor considered by road authorities in the seasonal frost areas. Axle loads that would not normally damage a pavement may cause significant damage during the spring thaw season. Consequently, road authorities impose seasonal load restrictions on the heavy axle loads to minimize pavement damage. In Provinces where the demand of the heavy equipment increases as in Alberta, satisfying the legal axle load is a challenge facing the heavy equipment operators. In Alberta, the Nisku test road was built and instrumented to investigate the seasonal variation of pavement response under the heavy vehicles. Nisku test road description and instrumentation design are presented in the research. Also presented in this research is the seasonal variation of the pavement response, which was measured in the field for Hot Mix Asphalt (HMA) pavement, under the standard and heavy axle loads for five seasons, spring 2005, fall 2005, winter 2006, fall 2006 and winter 2007. The analysis includes the calculation of the Load equivalency Factor (LEF), the verification of the subgrade resilient modulus (Mr) that are presented in APDM 97 and the determination of pavement structure that accommodates the heavy vehicles. Finally, a case study is presented using two major highways (Highway 63 and Highway 881) to investigate the effect of running the heavy axle loads on pavement structure. A Life Cycle Cost Analysis (LCCA) is performed for two different pavement structures for a service life of 20 years.