Compaction and consolidation characteristics of lateritic soil of a selected site in Ikole Ekiti, southwest Nigeria

The compaction and consolidation characteristics of lateritic soils in Ikole area of Ekiti State were investigated. The investigation was carried out through laboratory tests on disturbed and undisturbed soil samples obtained from three borings (BH1, BH2, and BH3) of Holy Apostolic Nursery/Primary School, Ootunja, Ikole Local Government Area (L.G.A.) of Ekiti State Southwest, Nigeria. The soils are all lateritic and mostly fine-grained. Compaction tests indicate maximum dry densities of 2.05Mgm-3, 1.78Mgm-3, and 1.69Mgm-3 at optimum moisture contents of 14.3%, 20.7% and 19.6% for soil samples obtained from BH1, BH2 and BH3 respectively. Compression indices (Cc) obtained from oedometer tests are 0.04816, 0.03820 and 0.04318 while the calculated coefficients of volume compressibility (mv), are 1.308*10-4, 1.065*10-4 and 1.093*10-4 m2kN-1 for samples in BH1, BH2 and BH3 respectively. The unsoaked California Bearing Ratio (CBR) value at 2.5 mm penetration ranges from 42.10% to 92.40% and CBR value at 5.0 mm penetration ranges from 52.70 to 89.10% indicative of good materials for road subgrade, sub-base and base courses.Keywords: Compaction, Consolidation, CBR, Southwest Nigeria

THE EFFECT OF PARTIAL REPLACEMENT OF FINE AGGREGATE WITH LATERITIC SOIL ON THE COMPRESSIVE STRENGTH OF SANDCRETE BLOCK.

This work seeks to find a way in which lateritic soil within Ota, Ogun State of Nigeria could be use in the production of hollow sandcrete blocks. This replacement is intended to observe the effect of lateritic soil on the strength characteristic when employed in the production of sandcrete blocks. It was deduced from past works that the inclusion of lateritic soil in sandcrete block production will produce a lesser quality blocks but this work seeks to find the maximum permissible replacement that will still make the blocks be within the recommended standard. Sandcrete blocks were produced with each lateritic soil samples from different sources replacing the conventional fine aggregate, sand, in steps of ten percent (10%) to sixty percent (60%) and their compressive strengths determined and compared with that of a standard sandcrete block to check for the acceptable percentage replacement. Tests like gradation tests which include sieve analysis and hydrometer test, compaction test to determine the bulk density, Atterberg’s limit test, specific gravity test were performed on the lateritic soil samples to characterise the soils. The blocks were cured by sprinkling them with water twice daily till the twenty seventh (27th) day. In the compressive strength test, seventy two (72) numbers of 225 x 225 x 450mm hollow laterised sandcrete block sizes were produced and crushed with the compressive strength machine to determine their twenty eight-day compressive strength. Classifying the lateritic soil samples with the Unified Soil Classification System (USCS), it was found out that the lateritic soil is sandy silt of high plasticity and can replace sand by twenty percent (20%). This percentage replacement can be recommended to the block moulding industries within Ota