Effect of Engineering Properties of Soil on Pavement Failures in Ogbagi - Akoko Area, Southwestern, Nigeria

Abstract

Geotechnical properties of lateritic soil from 8 failed and 2 un –failed sections of road along Ogbagi and Arigidi Akoko, Southwestern Nigeria were investigated to determine the causes of the road failure. Tests carried out were natural moisture content, specific gravity, grain size distribution, atterberg limits, linear shrinkage, compaction and California bearing ratio. From the test results, natural moisture content ranged between 6.75 and 25.5 %, specific gravity (2.68 and 2.76), linear shrinkage (5.7 and 11.4 %) , maximum dry density (1483 and 1780 kg/m³), optimum moisture content (13.5 and 26.0 %), CBR (14 and 31%), liquid limits (31.1 and 53.5 %), plastic limits (0 and 28.2 %) and plasticity index (0 and 29.5 %). Factors responsible for the failure of the pavement are stress induced associated with high swelling of the soil due to ingress of water through joints or cracks, poor engineering properties of the soil due to high percentage of fine materials or clayey nature of topsoil/sub-grade soil below the pavement, poor compaction and drainage systems of the road.

Keywords: Atterberg limits, Engineering properties, lateritic soil, pavement failures, grain size