High performance gravel roads : gravel road specifications in South Africa and their impact.

Research on the performance of gravel roads in South Africa during the 80s resulted in innovative performance related guidelines published in the national guideline document (TRH20). Apart from re-evaluation and adjustments on the Gravel Road Management System, proper design and strict control on all regravelling projects were reintroduced during 1999. From the onset it became clear that improved performance and a much lower maintenance need could be expected. Detailed information gathered on 252 road sections provided the opportunity to evaluate performance and the impact of the improved standards on total transportation costs. Twenty road sections were selected and are monitored for this purpose. The paper describes the latest specifications, elaborates on the control processes, compares measured performance results with local and international models and quantifies the economic viability of improved standards and strict control. The purpose of this paper is to add value to existing research work and to provide information for improvement of local performance models. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E208431.