Characterization and Evaluation of Laterite Soils from Kaduna and its Environs for Road Construction Applications

G. O., Olajide, A. D., Bida and I. Isa

Department of Mineral and Petroleum Resources Engineering, Kaduna Polytechnic, Kaduna.

Keywords: Laterite soils, California Bearing Ratio (CBR), compaction parameters, plasticity index, permeability.

Abstract

This study investigates the engineering properties of laterite soils from Kaduna and its Environs, Kaduna State, Nigeria, with a focus on their suitability for road construction. Laboratory analyses were conducted to determine key parameters such as California Bearing Ratio (CBR), strength characteristics, compaction properties, and permeability, as well as index properties including specific gravity, liquid limit, plastic limit, linear shrinkage, and fine content. The results show that the specific gravity of the laterite samples ranged from 2.54 to 2.8, indicating moderate to high particle density. The liquid limit varied between 32.5% and 57%, while the plasticity index ranged from 3.8% to 30.3%, suggesting a broad variation in soil plasticity. Linear shrinkage values were between 6.7% and 11%, and fines content ranged from 36.4% to 60.9%. The optimum moisture content (OMC) varied from 10.94% to 20.51%, and the maximum dry density (MDD) ranged from 1747 kg/m³ to 2056 kg/m³. The un-soaked California Bearing Ratio (CBRU) ranged from 14.7% to 45.6%, and the soaked CBR (CBRS) varied between 10% and 31%. Permeability values were between 6.30e-08 cm/s and 1.71e-05 cm/s, indicating low to very low permeability. These findings suggest that the lateritic soils from the study area have moderate to high compaction potential and sufficient strength for road construction, although soils with higher plasticity may require stabilization for improved performance. Stabilization with materials like lime or cement could enhance compaction, strength, and workability, ensuring the long-term durability of road infrastructure in the region.