Design method of asphalt mixture with balanced noise reduction and mechanical properties

A design method of asphalt mixture is proposed for reducing the tyre/road noise while having good mechanical properties. Firstly, by comparing the simulated sound absorption coefficient curve with noise-frequency curve from practical road surface, the target air voids contents are obtained. Then, models which can predict the texture level and sound absorption coefficient from the given mixture properties, such as porosity, gradation, particle size, asphalt content, etc. as inputs parameters, are used for preliminarily selecting the design parameters of mixture. Test samples are made according to these selected design parameters in the lab. Test vales of the texture level, sound absorption coefficient and the skid resistance of the mixtures are obtained from laboratory measurements. These measurement values are used for predicting the attenuation of the tyre/road levels by means of statistical models. Mixtures with superior predicted noise reduction properties are selected for mechanical performance validation. Mixture design which shows the promising noise reduction properties as well as satisfying the mechanical performance requirement are considered as the optimal one, and it is suggested to be used as the road surface. Road surface designed from this method can both meet the needs of traffic load and noise reduction function.