Applicability of Existing Gravel-Road Deterioration Models Questioned

Abstract

Efforts by the Provincial Government of the Western Cape in South Africa to improve all aspects of gravel-road construction and maintenance since 2001 have resulted in such good performance that existing gravel-road performance models are of limited value in predicting future needs and properly evaluating the need for upgrading to surfaced standards. The performance of several well-constructed road sections, representing different age groups, climates, material properties, and traffic spectra, has been monitored since 2003 and compared with the prediction of various internationally accepted roughness and gravel-loss deterioration models. A background summary of the improved processes, a brief summary of the experimental design, and a discussion of existing models are presented, with emphasis on the immediate and potential future impact of results that were obtained over a period of almost 3 years. Improvements to performance models are suggested, and the impact at the project level and on strategic-level analysis and decision making is highlighted. Recommendations are made on periodic maintenance strategies based on potential economic, social, and environmental benefits.