Collaborative Research Programme on Highway Engineering Materials in the SADC Region. Volume 1. Performance of Low Volume Sealed Roads: Results and Recommendations from Studies in Southern Africa.
The overall aim of the research programme has been to investigate the use of natural gravels for roadbases and to recommend innovative approaches for their use in a way that is cost-effective and environmentally sensitive.
Sections of road were selected on the existing road networks in Botswana, Malawi and Zimbabwe, and these were tested and monitored to enable designs to be evaluated.
The research focused on measuring how road pavements performed with time and traffic, and in different climatic conditions. It also identified features which need to be included in the road design to minimise risk.
This report presents a brief description of the test sections and the monitoring techniques used to collect pavement performance data. Local and other pavement design procedures are presented and discussed. The data collected from the field have been summarised and are supplemented by laboratory investigations of the pavement materials. The methodology for the data analysis is given and comments and recommendations are made on the appropriate use of marginal pavement materials and the introduction of a new structural and materials design procedure for low volume roads in the region. An analysis of the performance of the test sections to date is given and the influence of seasonal moisture variations on the strength of the pavements has been assessed.