Recommendations on the use of marginal base course materials in low volume roads in South Africa

Abstract

An investigation into the performance of 57 sections of road in South Africa identified by the Provincial Road Authorities as being constructed using marginal quality base course materials has been carried out. The investigations has shown that, apart from conserving precious construction materials and reducing the maintenance requirements of the previously unpaved roads, a significantly better level of service was achieved with a concomitant reduction in road user costs. Although the roads have required intermittent maintenance during their lives, they have clearly shown that current materials standards may be too conservative for affordable low volume roads. The study has shown that good drainage and construction quality are the primary requisites for successful low volume roads. A relaxation of the strength requirements for these roads is proposed.