PAVEMENT MATERIALS FOR LOW VOLUME ROADS IN SOUTHERN AFRICA: A REVIEW

Some requirements and specifications for pavement materials for low volume roads in developing areas in southern Africa are reviewed and it is shown that greatly inferior materials can be successfully used in all layers from surfacing chippings downwards under favourable circumstances of drainage and/or climate, traffic, maintenance and political and public opinion. In selecting such materials for the base and lower layers more weight should probably be attached to the CBR or triaxial strength attained in the road than to grading and plasticity, but allowance also has to be made for the effect of geological material. Considerable scope exists for the development of the optimum material specifications and construction procedures for local conditions.