Use of waste and marginal materials for silent roads

Inhabitants of the urban environment are exposed to high levels of traffic noise and increase in amounts of waste. One way to mitigate their exposure to noise is to take advantage of the existing public spaces between buildings and transform the available surfaces of pavements into elements that foster comfort and health for urban residents.
This work aims to develop low noise pavements by using certain waste materials. Semi-dense asphalt (SDA) mixtures (Air Voids = 12-16%) is used in this study due to their acoustic properties. Part of the aggregate matrix incorporates crumb rubber (CR). The various mixtures produced are compacted into 100mm dimeter specimens and subjected to texture measurements by 3D laser profilometry, porosity measurements and sound absorption measurements by the impedance tube method (EN 10534-2). The SDA mixtures showed a higher surface macrotexture amplitude, MPD. They also showed a more negative surface profile Rsk, indicating better noise properties based on the shape. This study gives us an understanding on how waste materials impact the texture and acoustic properties of roads and ultimately, to what degree they can be incorporated in low-noise asphalt mixtures.