The environmental effects of road construction are reviewed in terms of the high demand for conventional aggregates and binders and the motivation to use waste and recycled materials. It is noted that current composition-based specifications inhibit, to some extent, the use of these alternative materials and that the adoption of performance specifications will facilitate their introduction. The development of low-noise surfacings is described, with detailed attention being given to porous asphalt and to exposed-aggregate concrete. These two materials provide significant improvements in noise emissions when compared with conventional bituminous and concrete surfacings. Future trends, particularly Future trends, particularly on heavily trafficked highways, are for longer-life road construction which will cause less delay to traffic because of road maintenance. The development of European Standards and the increase in technology transfer and innovation are seen as ways in which environmentally advantageous innovations can be implemented. (A)
Abstract