Geotechnical Properties of Azara Soil as Base and Subbase Materials for Road Construction

Abstract

Road transport is one of the most important means of transportation and is pertinent to national growth and development. The materials used for road construction can determine whether it will last or not. This study investigated the geotechnical properties of Azara lateritic soils from Northcentral Nigeria for their potential use as base and subbase material in road construction. Six (6) samples were taken at about 2.5 m intervals each along an exposed cliff and subjected to laboratory analyses. All analyses were carried out following the British Standard. The required parameters for soils to be considered as base and subbase materials in road construction such as grain size distribution, Atterberg consistency limits, and maximum dry density were determined using the BS 1377 1990 standard. Results obtained show that the grain size analysis of the soil samples is silty clayey sand and clayey sand. The results of the Atterberg limit show that the samples can be grouped as low clay soils and medium clay soils. Compaction test analysis shows that sample SC has the highest optimum moisture content (OMC) value of 10.25%. Sample SB has the highest maximum dry density (MDD) value of 1.95 g/cm³ while samples SC has the least MDD value of 1.52 g/cm³ for the modified compaction test. Owing to the lateritic composition and compliance with Nigerian regulatory norms for geotechnical qualities, the lateritic soils found across the research region must be stabilized before they can be used as either base or subbase materials.