THE LOCATION, SELECTION AND USE OF CALCRETE FOR BITUMINOUS ROAD CONSTRUCTION IN BOTSWANA

摘要: A long term project has been undertaken to specify the use of calcrete for road construction in Botswana, under different conditions environment, design and traffic. Calcrete is a rubbly or powdery calcareous material that occurs within Kalahari sand, association with number distinct landforms. Research focused upon distribution calcretes possible soft types highway engineering. This report describes aims project, concentrating on survey mapping aspects. The study compared remote sensing techniques identify landforms corridor between Jwaneng Ghanzi (17,000 sq km), considered be typical southern Botswana. Tests strips colour multi-spectral small format aerial photography were specially flown, but it was found full range can identified using standard black white photographs, which provide good detail sterioscopic view, landsat imagery, gives differentiation, especially when digital images are enhanced by computer. engineering properties studied laboratory site. It recommended grading, hardness plasticity measured field as an initial assessment quality. scale experiment, constructed calcretes, including types, successfully carried more than 100,000 equivalent axles traffic, used establish new specification sealed bases lightly trafficked roads. Recommendations given planning surveys, map showing potential sources area included. (Author/TRRL)