Research On Material Composition And Noise Reduction Performance Of Skeleton Dense Asphalt Rubber Concrete

In recent years,noise pollution has become increasingly serious due to the increasing number of vehicles.Thus,it's necessary to develop low noise asphalt pavement with noise reduction ability to mitigate the noise pollution.In this paper,rubber powder was chosen as raw material of noise reducing pavement for designing skeleton dense asphalt mixtures with noise reduction ability,and their properties were studied and analyzed.Fineness and mixing amount were two important factors of rubber powder.Thus,the influence of fineness and mixing amount of rubber powder on penetration,softening point,ductility,viscosity,elastic recovery and rheological properties of rubber asphalt were studied comprehensively to put forward reasonable suggestions for evaluation of asphalt rubber.The skeleton dense asphalt rubber Concrete(SDARC-13)was designed according to the SMA-13 and AC-13C gradation range and successful experience.Besides,the pavement performance of SDARC-13 asphalt mixture was compared with other types of asphalt.Asphalt mixtures with different mixing methods and different mixing amount of rubber powder were tested by the method of dynamic modulus and damping trials.The acoustical absorption coefficient of different gradations of asphalt mixtures(e.g.SDARC-13,AC-13,SMA-13,OGFC-13)were measured by double-microphone transfer function method.It was found that The optimal mixing amount and mesh number of rubber powder were found to be 20%and 60-80 mesh respectively.SDARC-13 asphalt mixture exhibited benign high-temperature stability,water resistance and low-temperature crack resistance.the viscoelasticity of asphalt mixture was improved by addition of rubber powder,and the vibration damping ability of rubber asphalt pavement was enhanced as the mixing amount of rubber powder increased.Furthermore,compared to internal mixing,external mixing of rubber powder might be beneficial to reducing tire/road noise.sound absorption performances of asphalt mixtures were related with their thickness,frequency and porosity.Moreover,asphalt rubber mixture exhibited better sound absorption performance over ordinary asphalt mixture.After a comprehensive comparison and analysis of damping vibration and sound absorption ability of asphalt rubber mixture and ordinary asphalt mixture,we concluded that asphalt rubber pavement reduced noise mainly through damping vibration attenuation rather than sound absorption.