The development of low noise surface textures for rigid pavements

Portland cement concrete (PCC) pavements are being more widely adopted in Australia of late, particularly in high speed road and freeway situations. With the ever increasing demands to minimise the adverse environmental impacts of roads, considerable attention has therefore been focused on the traffic noise attributes of PCC pavements. Surface macrotexture is perhaps the major factor influencing these traffic noise characteristics. The present paper is based in part on a major aspect of an ongoing research and development program undertaken by the NSW Roads and Traffic Authority and the Cement and Concrete Association of Australia aimed at developing quieter PCC pavements without compromising other important factors such as skid resistance. Trial sections of varying surface texture have been constructed along freeways in New South Wales, close to Sydney. The surface texture of these pavements has been modified by altering the form of the pattern impregnated into the mortar whilst still plastic. Field tests and empirically based theoretical analyses have subsequently determined the acoustic properties of these surface types. The paper describes this research program, presents the empirical and analytical results and culminates with a discussion and conclusions concerning the minimisation of the noise produced by PCC pavements.