Study On The Sound Absorption Coefficient Of Porous Asphalt Pavement

With the rapid development of urban construction,traffic volume increases year by year.Road traffic noise has become a problem that cannot be ignored.This thesis takes porous asphalt pavement as the research object.Porous asphalt pavement is also called drainage asphalt pavement.Porous asphalt has large void structure that allows rainwater to infiltrate into the pavement,thereby improves pavement skid resistance and has a positive significance for city’s water balance.Porous asphalt pavement also can reduce traffic noise levels.However,most research on porous asphalt pavement focuses on drainage performance,less on noise reduction,and there is no systematic research on the noise reduction mechanism and material properties of porous asphalt pavement.Based on the acoustic characteristics of porous pavement,this article analyzes pavement noise control methods to reduce the generation and propagation of tire/pavement noise,as well as the materials,structural characteristics and noise reduction methods of different noise-reducing pavement.It is known that porous asphalt pavement has good noise reduction performance.Comparing different tire/pavement noise test methods,the laboratory two-microphone transfer function method was selected to test the sound absorption coefficient in this article.It has been experimental verified for studying the sound absorption performance of different pavement materials parameters based on the theoretical analysis.The research results indicated that the higher porosity of the porous asphalt pavement,the better was the sound absorption performance;The nominal maximum aggregate size had no significant effect on the sound absorption coefficient;Limestone had more significant sound absorption than diorite and granite;Compared with dry porous asphalt pavement,the sound absorption effect of saturated was worse;Within a certain noise frequency range,the thickness had an impact on the pavement sound absorption performance,The larger thickness of the test piece,the lower was frequency of the peak sound absorption;Under the condition of equal porosity,the peak sound absorption coefficient,noise reduction coefficient andaverage sound absorption coefficient of the horizontal test were all smaller than the vertical test;The porous asphalt pavement had good sound absorption performance.In the case of a certain total thickness,the effect of increasing the upper layer thickness on the sound absorption coefficient was in the form of a "hump",that is,as the upper layer thickness increase,the average sound absorption coefficient increase and then decreased.Road surface with high porosity,suitable density of coarse aggregate,dry pavement,and drainage asphalt pavement with reasonable pavement thickness selected based on the actual noise frequency range will had better vertical sound absorption performance.Asphalt pavement had better sound absorption properties than the horizontal.Double-layer porous asphalt pavement has excellent sound absorption performance in terms of noise reduction,skid resistance,and durability.Therefore,when selecting the materials and structural that improve the sound absorption performance of the pavement,the noise reduction effects of different parameters should be considered in order to achieve on optimal solution of road sound absorption performance.