Geotechnical properties of lateritic soil from Nimo and Nteje areas of Anambra State, Southeastern Nigeria

Abstract

The strength and durability of materials used as subbase and subgrade for pavement design and construction are the main factors determining the performance and service life of highway pavements and airfields. This study investigates the geotechnical properties of lateritic soils from Nimo and Nteje areas of Anambra State, Southeastern Nigeria. The soil samples obtained from the two study areas are hereinafter referred to as LAT-1 and LAT-2 for Nimo and Nteje areas, respectively. The samples were collected at depths ranging from 1 to 1.5 m, and were analyzed at the Anambra State Materials Testing Laboratory, Awka. Geotechnical tests such as Atterberg limits, Standard Proctor Compaction, California Bearing Ratio (CBR), Tri-axial tests and Particle size Distribution analysis were conducted on the soils. All the geotechnical tests were done in accordance with the ASTM and British standards. The soil samples were classified as A-2-7, while the unsoaked CBR values of the soils were 0.89 and 1.43 % for LAT-1 and LAT-2, respectively. The Plasticity Index and Maximum Dry Density of the soils were 21 and 17 %, and 1.93 and 2.19 Mg/m3 for LAT-1 and LAT-2, respectively. Similarly, the effective friction angle and effective cohesion of LAT-1 and LAT-2 were determined as 13.54 and 22.09°, and 38.72 and 10.43kPa, respectively. It was found that the lateritic soil from Nteje (LAT-2) showed higher strength and compaction properties than the soil from Nimo (LAT-1). However, the general trend of the results indicates that the lateritic soils are not suitable for use as subbase and subgrade in pavement construction.