Engineering Properties of Sub-Soils Along Akungba-Ikare Road, Southwestern Nigeria: Appraising the Effect on Road Construction

Abstract

This study is aimed at determining the strength and suitability of subsoils along Akungba-Ikare road, Southwestern Nigeria, as underlying materials for the purpose of engineering constructions. In order to achieve this, ten representative soil samples (D1-D10) were taken from the field and the following laboratory soil tests were conducted on these samples: particle size analysis test, Atterberg limit test, compaction test, specific gravity, consolidation test and California bearing ratio. The particle size analysis for the 10 sampled soils show that the percentages passing number 200 BS sieve are 22.3%, 28.4%, 47.1, 79.7%, 33.8%, 79.1%, 79.8%, 60.1%, 35.4% and 32.5% respectively. Samples D1, D2, D5 and D10 can be deduced as suited for sub-grade, sub-base and base materials as the percentage by weight finer than N0 200BS test sieve is less than or equal to 35%. The values of natural moisture content range, liquid limit, plasticity index, linear shrinkage and specific gravity ranged between 19.6% and 28.5%; 25.3 % and 60.4%; 0.9% and 44.1%; 3.6% and 12.1% and 2.57 and 2.68 which classified these soils as either sand or silty sand. 3 The Maximum Dry Density (MDD) for the sampled soils range between 1754kg/m to 2009kg/m while that of 3 optimum moisture content (OMC) ranges between 12.2% and 17.3%. The unsoaked California bearing ratio values for the subsoil samples range between 26% and 50%. These CBR results show that the soils are only suited for sub grade course and not sub-base and base course. Based on AASHTO classification, four (40%) of the ten sampled soils has good rating for sub-grade and sub-base. Five (50%) samples have fair rating while the remaining one (10%) samples have poor sub-grade rating. The rate of settlement ranged between 0.58mm/yr and 1.21mm/yr with samples D1, D2, D5 and D10 having values less than 1mm/yr. This implies that the other values will settle under continuous movement of heavy duty trucks.

Publication Info:

Author: Ale, T.O.

Volume: 57

Issue: September

Published By: Journal of Mining and Geology, 2024-09-01