Sustainable Approach to Maintenance of Low Trafficked Surfaced Roads

Abstract

Road asset owners are faced with the dilemma of having to maintain their ageing bituminous sealed road networks with limited funds. This challenge has to be managed while trying to preserve their scarce natural resources, meet community expectations of acceptable service levels and maintain roads that are rapidly deteriorating due to either increased traffic volumes or the oxidisation of the binder in low trafficked road surfaces. This paper will look at various techniques that can be employed to help extend the life of the original surfacing in lower trafficked environments thereby reducing the demand on non-renewable resources like aggregates and bitumen. This is primarily achieved by reducing the propensity of the bituminous binder from becoming brittle and cracking due to oxidation. This includes extending the life of the existing bituminous surfacings through various cost effective techniques and strategies such as: • changing elements in the design and construction of the seal and asphalt used in the original surfacing, and • timeous intervention during the service life by using a range of cold applied bituminous emulsion surfacing techniques. The concept of timeous intervention involves treating the ageing surface to extend its life and therefore delaying the cost of more expensive and resource hungry maintenance activities like pot hole repairs and resurfacing. The typical treatments range from using dilute bitumen emulsion enrichments to applying a thin coating of special polymer modified bitumen emulsion treatments to thin layer microsurfacing. The use of emulsions technologies helps achieve the goal of improving the sustainability of road provision by making use of a cold application technique which: • eliminates the risk of workers being burnt during handling of the products • reduction in odours and vapours during application • reduction in energy required during the handling and application processes. This paper will report on the use of these treatments in different applications and their cost effectiveness.