Study on Roughness Wavelength of Semi-rigid Base Asphalt Pavement
To study the relation between pavement roughness wavelength and dynamic load,and to identify the wavelength range of semi-rigid base asphalt pavement,the typical expressways and third-grade highways are selected as test roads.The heavy-duty vehicles and light-duty trucks are taken as test vehicles with full load and no load conditions.The self-developed wireless vehicle axle vibration acceleration measurement instrument is installed on the rear axles of test vehicles.The time-domain characteristic data of vertical vibration of vehicle axle are obtained from the field test.The frequency-domain characteristics of vehicle vibration are obtained through Fourier transform.According to the relation among frequency,vehicle speed and wavelength,the roughness wavelength range of semi-rigid base asphalt pavement is calculated and divided.The result indicates that the standard deviation of axle vibration acceleration can be used as a direct indicator of vehicle dynamic load,and the standard deviation of axle vibration acceleration increases with the increase of vehicle speed and road roughness.The typical frequency domain curve of vehicle vibration on semi-rigid base asphalt pavement consists of 2 primary resonance frequencies and one secondary resonance frequency.The pavement roughness wavelength can be divided into 4 wave bands,which are 0-0.2 m ultrashort wave,0.2-1.4 m short wave,1.4-5.6 m medium wave,and 5.6-100 m long wave.The ultrashort short wave and long wave have little influence on dynamic load generated by vehicle vibration,and the short wave and medium wave have greater influence on dynamic load generated by vehicle vibration,among which the medium wave of 1.4-5.6 m has the greatest influence on dynamic load generated by vehicle vibration.The test result can be used as a new standard for division of roughness wavelength semi-rigid base asphalt pavement,and provide a basis for formulating the construction control standard of roughness of semi-rigid base asphalt pavement.
road engineeringroughness wavelengthFourier transformsemi-rigid base asphalt pavementdynamic loadpavement roughness
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