Comparative Analysis of the Dynamic Cone Penetrometer-Cone Penetration Rate Design Approach against Other Methods Used for Upgrading of Low Volume Roads: Case of Uganda and Zambia

Abstract

Low volume roads form a significant part of the road network in Sub-Saharan Africa (SSA). During the dry season, these often unsurfaced (predominantly gravel) roads generate a lot of dust which is a health hazard and has adverse effects on the environment. In the wet season, some sections of these roads become impassable thereby limiting accessibility and disrupting economic activities. Rapid depletion of gravel sources for road construction has rendered the re-graveling of these roads unsustainable. On the other hand, upgrading these roads to bituminous standard using conventional design approaches would be costly given the vastness of the network in question. For sustainability, it is imperative to explore alternative approaches for design of low volume sealed roads (LVSR). Research in the region has highlighted the dynamic cone penetrometer-cone penetration rate (DCP-DN) method as one such plausible approach. In the DCP-DN design approach, the DN value is used directly, without correlation with the California bearing ratio (CBR). This paper provides a comparison of the DCP-DN pavement design method with other common methods for design of LVSR in SSA—particularly Uganda and Zambia. In both countries, the DCP-DN method was found to be a promising alternative for pavement design of LVSR in relation to potential reduction in cost of implementation of the pavement layers that resulted from the design.