| Traffic noise is one of the main sources of urban noise pollution.With the development of economy and society,the requirements for urban noise control are improved gradually.Reducing the noise caused by air pumping and vibration between tire and pavement surface is an effective method to reduce urban traffic noise.However,at present,the pavement structure of most roads in China does not have the function of noise reduction.The realization of noise reduction effect of pavement structure is an urgent technical problem in the field of road construction.In view of the above problems,based on the void sound absorption characteristics and damping characteristics,the multi-voids rubber asphalt mixture was prepared to determine its sound absorption,vibration reduction and noise reduction performance,so as to reduce the noise pollution of urban road traffic.The generation and control mechanism of asphalt pavement traffic noise was analyzed systematically.Based on the noise reduction performance caused by absorption and vibration reduction,multi-voids rubber asphalt mixture was prepared.The sensitivity of influencing factors on sound absorption performance of multi-voids asphalt mixture was calculated and analyzed by equivalent fluid model..A Three-Dimensional reconstruction model of multi-voids asphalt mixture was established based on CT scanning test,and the characteristic parameters of void structure such as void ratio,pore size distribution and void shape were obtained.The evaluation index of sound absorption performance based on specific frequency band was proposed,and the correlation between void characteristic parameters and noise reduction performance was determined.The connected porosity increased from 14.98%to 16.53%,and the sound absorption efficiency in medium and high frequency areas increased by 4.5% and 13.1%,respectively.The asphalt mixture with large void fraction and large particle size had obvious sound absorption efficiency for medium and high frequency noise.The asphalt mixture with large void fraction and small particle size had good noise absorption performance in low frequency band.The damping ratio of multi-voids rubber asphalt mixture was tested by hammering vibration modal analysis test.Based on the multi spectrum sound pressure test system,the tire drop test was used to comprehensively test the sound pressure generated by the tire hitting the asphalt mixture specimen.The correlation between damping performance and noise reduction performance of multi void rubber asphalt mixture was evaluated.The effect of adding rubber powder on vibration and noise reduction of mixture was clarified.Compared with the mixture without rubber powder,the damping ratio of the mixture with 20% rubber powder increased 16.88-37.36%.The increase of damping ratio led to the enhancement of vibration reduction effect of asphalt mixture.Compared with the asphalt mixture without rubber powder,the A-weighted maximum sound pressure level of asphalt mixture with 40 mesh rubber powder content of 20% reduced 2d B(A),and the instantaneous maximum sound pressure level reduced 2.4-4.9 d B.The field noise test of multi-voids rubber asphalt mixture pavement was carried out.The evaluation method of sound absorption and noise reduction performance based on frequency distribution characteristics was proposed.The correlation between sound absorption performance and actual noise reduction performance was analyzed.The influence of multi-voids asphalt mixture void sound absorption performance and vibration damping performance on pavement sound absorption and noise reduction performance was clarified.The design method of urban road multi-voids asphalt pavement based on traffic composition characteristics was proposed.This paper provides a technical basis for the design of multi-void rubber asphalt mixture,provides a solution for pavement structure noise reduction,and will be value for the promotion and application of multi-voids rubber asphalt mixture. |
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