Study on Noise Reduction and Sound Absorption Performance of Drainage Asphalt Pavement Based on Indoor Tire Accelerated Falling Method

In order to study the noise reduction and sound absorption performance of drained asphalt pavement—PAC, the difference of noise reduction and sound absorption effects of conventional AC pavement, single-layer and double-layer PAC pavement is compared and analyzed by improving the indoor noise test of tire accelerated falling method, and then the sound absorption coefficient of single-layer and double-layer PAC pavement is further tested by standing wave tube method, Based on the standing wave interference principle of sound, the sound absorption characteristics of drainage asphalt pavement are described, the influence of void ratio on the sound absorption coefficient of PAC pavement is analyzed, and the data model between void parameters and sound absorption coefficient is established. The results show that: (1)Using the improved indoor tire accelerated falling method and using the sound level meter to measure the A-weighted sound pressure level and 1/3 octave frequency spectrum of noise under three distance conditions, the noise value of drainage asphalt pavement is 2 to 5 dB(A) lower than that of traditional AC pavement, and the noise reduction ability decreases with the increase of distance from sound source and increases with the increase of void ratio. The sound absorption coefficient curve of drainage asphalt pavement is measured by standing wave tube double transfer function method, The average sound absorption coefficient of PAC specimens decreases with the attenuation of the void fraction.(2)The sound absorption coefficient curve of single-layer PAC pavement presents a "single peak type". The sound absorption peak frequencies of single-layer 4cm thick PAC pavement and 10cm thick PAC pavement are around 1100 Hz and 800 Hz respectively. The corresponding frequencies of the sound absorption peaks of the two specimens are within the common frequency range of traffic noise, which is helpful to alleviate traffic noise.(3)Through CT scanning and three-dimensional reconstruction software, the void parameters of PAC specimen are obtained, and the sound absorption coefficient prediction model is established. The sound absorption coefficient calculated by the model has a high correlation with the measured value of standing wave tube method, which verifies the accuracy of the sound absorption coefficient model in predicting the sound absorption characteristics of drainage asphalt pavement.