Study on correlation between voidage and sound absorption coefficient of urban low noise road pavement

With the development of China economy and auto industry, urban road noise increased rapidly, which seriously interferes with the normal lives and work orders of residential areas, schools, hospitals, job agencies and others on both sides of urban roads. At present, the urban road traffic noise pollution control in the urban environment has become a hot spot problem. And with the continuous expansion of city size and urban traffic, urban road traffic noise has gradually increased as an important factor which constraints the quality improvement of urban living environment. The noise reduction principles of porous asphalt pavement are analyzed. The correlations between different voidages, different modified asphalt additives and sound absorption coefficients are studied in large scale integrated noise laboratory. Many experiments show that: Porous asphalt pavement sound absorption coefficient have a great relationship with voidage; the sound absorption coefficients of the low voidage and dense gradation mixture test pieces are almost same, the sound absorption coefficients of porous asphalt mixture have peak value; porous asphalt mixture with more than 20% voidage has a high sound absorption coefficient at the frequency from 400 to 1000 Hz. The sound absorption coefficient increases as the voidage goes up. The results of this study provide basis for the design and study of urban road noise reduction pavement.