Rutting Failure on Pavement Layers along Timboroa to Eldoret Road Section in Kenya

Abstract

The Timboroa to Eldoret Road (A104) in Kenya forms part of the Northern corridor which is lifeline for several countries in the greater East African region. Traffic studies along the Timboroa to Eldoret highway indicate that the traffic mainly consist of transit traffic carrying import and export goods to and from the port of Mombasa in Kenya to the countries of Uganda, Rwanda, Burundi, Democratic Republic of Congo and part of Southern Sudan. Axle loading measurements show cases of overloading of the trucks which may have contributed to severe rutting failure of the flexible pavement in some sections. Current design standards and construction methods were reviewed in order to verify their impact on the pavement deterioration. Regression method of analysis was applied on the data obtained to correlate the results with pavement failure. Research findings from this study indicate that the major contributors to pavement distresses are the weak subbase layer and unstable subgrade used which has resulted to permanent deformation. Overloading factor associated with the heavy goods vehicles also plays a significant role. Other factors observed as contributing to rutting are the material characteristics of the base and subbase layers.