Assessment of Pavement Performance on Low-Volume Roads Constructed with Laterite Base in Ekiti State

Low-volume roads constructed with laterite base courses represent the dominant rural road typology in Ekiti State, South West Nigeria, yet their performance under tropical rainfall conditions and agricultural vehicle loading is inadequately documented. This study assesses the pavement performance of ten laterite-base low-volume roads in Ekiti State, comparing performance against design life expectations. Field investigations were conducted on 45 km of rural roads in Ado-Ekiti, Ikole, and Ijero LGAs. Road surface condition was assessed using the International Roughness Index measured with a smartphone-based roughometer mounted on a vehicle. Structural condition was evaluated using Dynamic Cone Penetrometer tests at 500-metre intervals. Surface drainage adequacy was visually assessed. Traffic counts provided loadings data. Results indicate that 68 percent of assessed road length has an International Roughness Index above 12 m/km, indicating poor riding quality. DCP-derived structural numbers fall below design requirements in 44 percent of tests. Roads in low-lying areas with poor drainage performance show IRI values consistently 35 percent higher than equivalent roads with adequate drainage. Roads exceeding ten years since last grading have significantly deteriorated structural performance. The study concludes that maintenance frequency and drainage management are the primary determinants of laterite road performance in Ekiti State, recommending annual grading and drain clearing as minimum maintenance standards.

Keywords: low-volume roads, laterite base, pavement performance, Ekiti State, South West Nigeria