Geotechnical characteristics of road construction soils stabilized with lime in Southwestern Nigeria

Abstract

The quality of the roads in Southwestern Nigeria is appalling; most are impassable owing to pavement collapses, prompting research into the feasibility of underlying soil courses if lime is used to stabilize them. This study used eighteen borrow pit soil samples for road construction (one from each Senatorial district in Southwestern Nigeria). Strength studies (compaction, California Bearing Ratio (CBR), and Unconfined Compressive Strength (UCS)) were conducted in the laboratory using standard procedures. 2, 4, 6, 8, and 10% of lime was added to the dry weight of soil to obtain the varied stabilized soil samples. The Maximum Dry Density (MDD), CBR, and UCS values all improved as the lime concentration increased, with the optimum being obtained at 6% lime addition. Although, there was an exception for OMC, which continued to increase with the increase in lime content up to 10%. Predominantly, unsuitable soil samples became suitable as pavement layer materials after stabilization with 6% lime. Hence, due to the improvement in their strength properties when stabilized with lime, the underlying soil courses in Southwestern Nigeria roadways should be stabilized with 6% lime content during construction for durable pavements.