Assessment of the Geotechnical Properties of Lateritic Soils in Minna, North Central Nigeria for Road design and Construction

Abstract

Laterite is a highly weathered material, rich in secondary oxides of iron, aluminum, or both. Geotechnical investigation is one of the effective means of detecting and solving pre, syn and post constructional problems. The geotechnical properties of lateritic soils and their suitability for road construction have been evaluated for selected sites in Minna, North-central Nigeria. All analyses were carried out in accordance with the British Standard Institution. The liquid limit ranged from 22.5% to 49.6% with an average value of 34.9%, plastic limits varied from 13.8% to 28% with a mean value of 21.38% while plastic index is of the order of 8.7% to 21.6% with an average value of 13.5%. The maximum dry density ranged from 1.78 g/cm3 to 2.33 g/cm3 with a mean value of 1.858 g/cm3 while the optimum moisture content varied from 6.30% to 14.3% with an average value of 9.74%. The evaluation reveals that the lateritic soils have higher plastic limits, Maximum Dry Densities (MDD) and California Bearing Ratios (CBR) while their liquid limits, plasticity indices and Optimum Moisture Contents (OMC) are lower. The lateritic soils were classified as A-3, A-2-4 and A-2-6 and are adjudged suitable for sub-grade, good fill and sub-base and base materials. This geotechnical information obtained will serve as base-line information for future road foundation design and construction in the study area.