Causes of Arch Expansion on Semi-rigid Base Asphalt Pavement Based on Temperature-stress Analysis
To investigate the issue of arch expansion on semi-rigid base asphalt pavements in northwest China,the mechanical behavior of asphalt pavements under actual service conditions was analyzed via practical investigation and numerical simulation.A method based on temperature-stress was proposed to assess the degree of arch expansion.First,the temperature field of typical semi-rigid base-layer asphalt pavements in Xinjiang was measured.The spatial and temporal distribution characteristics of temperature at different pavement depths were analyzed,and a pavement temperature-field estimation model was established to determine the temperature load under actual service conditions.Second,a pavement thermal and mechanical coupled numerical model was established to analyze the effects of temperature difference,base-layer modulus,and expansion coefficient on the temperature-stress and vertical deformation of the asphalt pavement.Finally,based on in-service pavement projects in the Xinjiang region,a field investigation on the base layer condition and arch expansion was conducted.The relationship between the arch-expansion degree and the temperature-stress on the base layer was established,and a categorization standard for the degree of arch-expansion development was determined.The results show a significant phase difference in the temperature distribution at different pavement depths in Xinjiang,and that the daily temperature fluctuation becomes flatter as the depth increases.The differences in the temperature gradient and temperature change rate result in different stress states in different structural layers at various moments.Within 30 cm below the road surface,the structural layer of the pavement experiences alternating tensile and compressive forces throughout the day,and the base layer is more susceptible to stress changes,thus resulting in more frequent arch-expansion deformation on the base layer.The degree of arch-expansion development increases with the modulus of the base layer and can be categorized into four grades:no arching,slight arching,medium arching,and severe arching.The results of this study can provide a reference for the nondestructive assessment of arch expansion and the design of pavement anti-arch expansion.
pavement engineeringarch expansion diseasenumerical simulationtemperature stresstemperature fieldbase layer modulusnumerical modeling of thermal and mechanical coupling
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