Sand cushioning is a process whereby a thin layer of sand is spread onto a road surface in order to reduce gravel loss, to minimise the transmission of the underlying roughness of the road surface to traffic and to limit base deterioration. Experiments have recently been carried out to investigate the sand cushioning process, to develop a specification and to quantify the benefits. A contractor development programme, whereby contractors can carry out this form of maintenance, instead of by the road authorities, has also been considered. Results of the investigation indicate that, provided the surface is regularly maintained with appropriate equipment (tractor drawn blade and tyre drag combination), riding quality is significantly improved and dust levels, gravel loss and general deformation of the road base are reduced. The study found that significant economic benefits could be gained if the system is correctly implemented. In this paper, a background to sand cushioning is provided, the method and equipment requirements are summarised and the benefits in terms of gravel preservation and reduced vehicle operating costs are discussed. The economic benefits of sand cushioning versus traditional maintenance methods in arid areas are compared. (A)
Samenvatting