Pavement

This report provides a review on surface characteristics in relation to traffic noise and long-life surfacings. For the conventional asphalt surfacings in general road construction practice, the selection of mix type and size would define two most important parameters (i.e. texture spectrum and air voids) affecting the noise contribution of the surfacing. Once a mix was selected, further noise reduction could be trialled by controlling the aggregate grading and binder content (two of the key factors in mix design) within the specification limits. Using aggregates from a different source could also be considered, since inherent aggregate characteristics (e.g. shape, microtexture) would also influence the noise contribution of the surfacing to a certain degree. Where an extremely low noise surfacing is required, special ‘low noise surfacing products’ can be considered. However, these products are not conventional and need to be examined and their performance validated as satisfactory in other more important aspects (e.g. resistance to traffic load, skid resistance, cost etc.).