چكيده انگليسي :
One of the most important transportation infrastructures is the physical network of roads. Because of the high costs of construction and reconstruction as well as the numerous negative effects on society when the roads are not in good working order, it is crucial to look into the factors accelerating the rate of deterioration of the roads. Due to the fact that the roads are continuously in contact with the environment, climatic factors, particularly temperature and precipitation, are among the variables affecting the quality and lifespan of the roads. Besides, according to the IPCC's reports the average air temperature is rising. It means that, p pavements encounter weather that they were not intended to resist. It may increase pavement distress rates and decrease pavement serviceability. This research uses 32 climate models at SSP2 and SSP5 to predict temperature and precipitation from 2030 to 2050. Subsequently, the long-term behaviors of interstate, primary and secondary pavements in 11 weather stations having different traffic and climatic conditions under historical and projected climate scenarios were predicted and compared using the Mechanistic-Empirical method implemented by the AASHTOWare Pavement ME Design. Finally, climate change's qualitative and quantitative effects on pavement performance were evaluated, and some solutions were suggested to make pavement more resilient.
The results show that increasing minimum and maximum air temperature causes two problems; first and foremost, since asphalt is a viscoelastic material, increasing maximum air temperature due to a decrease in asphalt modulus and more plastic deformation in the asphalt layer and consequently increasing AC rutting. Furthermore, growing minimum air temperature affects F-T cycles' duration and numbers, so that granular layers are saturated more than before. This phenomenon decreases the modulus of granular layers and their bearing capacity and can raise total permanent deformation, especially in cold regions. Consequently, International Roughness Index, AC, and total rutting respectively increase by 0-2%, 15-31%, and 0-15% for SSP2 scenario, which can reduce interstate, primary, and secondary pavements lifespan by 16-24%, 12-23%, and 10-17% respectively and also increase reconstruction costs by 20-42%, 16-39%, and 13-30% for interstate, primary, and secondary pavements. For SSP5 scenario, the range of Reduced Life is 15-26%, 16-31%, and 15-31% for interstate, primary, and secondary pavements, which can respectively increase reconstruction cost by 20-38%, 21-46%, and 20-39% due to increasing 0-4.6% of the International Roughness Index, 12-35% of AC rutting, and 4-15% of total rutting, respectively. It should be noted that increasing the number of reconstruction projects leads to an increase in the demand for materials and equipment, which increases CO2 emissions for interstate, primary, and secondary pavements by 16–25%, 11-27%, and 11-21% for SSP2 and by 14–29%, 15–45%, and 15–56% for SSP5.
In conclusion, considering the huge length and value of the roads, ignoring the effects of climate change and its economic and environmental costs will impose considerable costs on governments and users worldwide. Therefore, although preventing the indiscriminate emission of greenhouse gases is the ideal solution to stop such detrimental effects, in a situation where implementing such plans is not expected, it is possible to apply diverse kinds of engineering solutions to make pavement more resilient. This study effectively increases the binder's performance grade by a 5-15% decrease in distress threshold limits. The analysis results show that it can considerably prevent climate change's detrimental influences.
