The cost-effective upgrading, preservation and rehabilitation of roads - optimising the use of available technologies

Abstract

The provision and preservation of a good transport infrastructure is a prerequisite to economic growth. To be competitive in a micro as well as macro economy, any cost associated with and influencing production and delivery costs needs to be minimised ? transportation cost is a crucial component of this competitive regime. The high cost of the upgrading, maintenance and rehabilitation of the existing road infrastructure puts an ever increasing burden on available funds. This existing scenario of high cost increases makes it essential for design engineers to optimise designs using proven technologies and, together with client authorities, investigate, test and use improved seal, stabilisation and material enhancement technologies (e.g. through the use of available nano-technology) that are available and are continuously being developed all over the world. Unfortunately, new technology developed and successfully tested over the last decade in various parts of the world have, to a large extent, not been effectively utilised by the road building fraternity in South Africa. These developments, involving the use of nano-technology, enables the use of traditionally available stabilising agents at much lower application rates, achieving improved strength characteristics and more water resistant layers in roads at lower unit costs. The Gauteng Province Department of Roads and Transport (GPDRT) has identified this technology as a potential game-changer that will dramatically improve service delivery, specifically roads, in the province (and in effect the whole region) at an affordable unit cost. Consequently, the GPDRT has committed to test the available products on sections of roads and scientifically prove the cost-effective use of the available technology. This technology will be used on the Route D1884 between Vereeniging and Heidelberg for the recycling of the existing in-situ base-course. Both the CSIR with Accelerated Pavement Testing using the Heavy Vehicle Simulator (HVS) together with academics from the University of Pretoria will be involved in the thorough testing and the evaluation of the rehabilitated road. The ultimate aim is to provide road engineers with improved guidelines for the effective use of available in-situ materials as related to the properties of appropriate cost-effective stabilising agents.