Investigation of Flexible Pavement Failure along Ede – Akoda Road, Osun State, Southwestern Nigeria

Abstract

Ede to Akoda is a trunk B-road built over 30 years ago. It has been in despicable condition leading to fatal accidents and loss of life and properties that impacted negatively on the community. This study investigated the flexible pavement failure along the road in order to ascertain the possible causes of its failure. The methodology adopted covered reconnaissance survey, assessment of the physical condition of the road and soil investigation of subgrade. The result of reconnaissance survey revealed that the surface wearing course has degraded extensively. The physical inspections showed that considerable segment of the drainage facilities has collapsed or totally blocked allowing extensive ponding of rain water on the road surface. The pot holes were deep and widespread in most places and the road is near total collapse. The result of soil investigation revealed that natural moisture content, specific gravity, liquid limit, plastic limit, plastic index, maximum dry density and optimum moisture content were within the specifications of the Federal Ministry of Works and Housing limits (FMWH). However, the California bearing ratio values were less than minimum 10% stated in the specifications, this suggests the nature of subgrade soil as a possible cause of failure of road pavements along Ede-Akoda Road, Nigeria. It is recommended that further research be conducted on other structures of the flexible pavement to better ascertain the causes of the studied road failure.