Geotechnical Properties of Some Earth Materials Used for Road Pavement Construction in Anambra State

Abstract

This research project was carried out to investigate the geotechnical properties of some earth materials used in road pavement construction in Anambra State of Nigeria. Laboratory tests including particle size distribution analysis, specific gravity, Atterberg limits, compaction using the British Standard Light (BSL) and the British Standard Heavy (BSH) compactive efforts, and California Bearing Ratio (CBR) tests were conducted on the soil samples gotten from Agu-Awka, Nawfia and Ugwuoba designated LAT 1, LAT 2 and LAT 3 respectively. From the results obtained from the tests and using the liquid limit, plastic limit and plasticity index the soil samples fall into A-2-4 of the AASHTO classification and SC (Clayey Sand) using the USCS classification. The compaction characteristics of the samples were found to be 21.21KN/m³, 21.77KN/m³ and 21.23KN/m³ for maximum dry unit weight and 12.5%, 13.5% and 11% for optimum moisture content for LAT 1, LAT 2 and LAT 3 respectively. The California Bearing Ratio (CBR) results after 48 hours soaking is 23.5%, 25.7% and 24.2% for LAT 1, LAT 2 and LAT 3 respectively. These results obtained indicate that the samples meet requirements for sub-base since the Federal Ministry of Works and Housing specifies CBR values greater than 20% for subbase type 2 with low traffic loads.