Bio: O Omotosho is an academic researcher. The author has contributed to research in topics: Cement. The author has an hindex of 1, co-authored 1 publications receiving 8 citations.
TL;DR: In this article, samples of deltaic lateritic soils were subjected to mechanical (with or without controlled sand addition), cement and cement-sand (composite) stabilisation methods to improve strength for improved engineering applications.
Abstract: Deltaic laterite is the most suitable and most widely used soil material for road embankment in the Niger Delta. Usually, its natural characteristics fall short of the minimum requirements for such applications hence it has to be stabilised to improve its properties. In this study, samples of deltaic lateritic soils were subjected to mechanical (with or without controlled sand addition), cement and cement-sand (composite) stabilisation methods to improve strength for improved engineering applications. Mechanical stabilisation was found to satisfy subgrade requirements while the addition of sand produced sub-base material quality at best depending on compacted maximum dry density (MDD), which itself is dependent on the optimum sand content (OSC). The OSC was also shown to affect the optimum moisture content (OMC) and the soaked California bearing ratio (CBR) of stabilised specimens. Combination of the test results produced a graphical model to predict the influence of mechanical stabilisation on the soil materials using the percentage fines (that is, passing through a 75 mm sieve) obtainable from wet sieving. Cement stabilisation of the soil (by indigenous highway standard) produced base-course quality materials with cement content in excess of 12 %, which is economically unviable. However, the addition of controlled proportions of sharp sand (also abundant in the Niger Delta) to the soilcement mixtures produced base-course quality materials with 6 % cement (less than half of that obtained through only cement stabilisation) and about 40 % sand content. A model was also presented to predict the other constituents of sand-cement stabilisation using the percentage fines obtainable from wet sieving.
01 Jan 2014
TL;DR: In this article, the authors used integrated surface electrical resistivity survey, borehole drilling and insitu testing by CPT to determine engineering geological properties of soils underlying Warri metropolis for the planning and design of civil engineering structures.
Abstract: Integrated surface electrical resistivity survey, borehole drilling and insitu testing by CPT were used to determine engineering geological properties of soils underlying Warri metropolis for the planning and design of civil engineering structures. Results revealed that three major sub-soil types underlie the area characterized by dry, swampy and marshy ground conditions. These soils occur in the dry plains and swampy areas, from top to bottom, as silty sand, clayey sand and sand. However in the marshy NPA area, only two soil layers occur: the top 6m thick organic clay layer overlying the sand layer. The geotechnical properties suggest that all the layers can support structural loads from civil structures, provided foundation design is preceded by adequate subsoil investigation to provide construction specific data.
01 Jan 2011
TL;DR: In this article, the mean value of the optimum moisture content of less than 12% suggests that during dry season, road construction work in the field may not be a major problem.
Abstract: This study was carried out with aim of providing a valuable data base for emerging road construction engineers involved in opening up the rural areas for extensive petroleum exploration activities. A total of 152 samples were randomly collected with different geotechnical parameters tested according to the British Standards. The soils are generally fine to medium grained consisting mainly of clayey sand and sandy clays with low to medium plasticity. The mean value of the optimum moisture content of less than 12% suggests that during dry season, construction work in the field may not be a major problem. The soaked CBR values range from 3 to 43%. This falls below the stipulated 180% by Federal Ministry of Works for base course material. Consequently, this suggests that these soils should be subjected to some forms of stabilization to ensure the durability of roads in this region.
TL;DR: In this paper, the influence of leaching on the physicochemical behaviour and durability of lime-stabilised lateritic soil under continuous water ingress, simulating the typical experience in a tropical environment was evaluated.
Abstract: Lime stabilisation is one of the traditional methods of improving the engineering properties of lateritic soils for use as subgrade and foundation materials for the construction of road pavements and highway embankments. Understanding the mechanical performance of lime-stabilised lateritic subgrades in terms of their durability under continuous water ingress will improve environmental sustainability by conserving scarce natural resources and reducing the environmental impacts of repair and replacement of pavements. However, there are several conflicting reports on the durability of lime-stabilised soils subjected to continuous water ingress and harsh environmental conditions. Therefore, this paper evaluates the influence of leaching on the physicochemical behaviour and durability of lime-stabilised lateritic soil under continuous water ingress, simulating the typical experience in a tropical environment. Variations in the strength and durability of the lateritic soil at various lime contents (0, 2.5, 5, 7.5, 10, 15, and 20 wt.%) and soaking periods (3, 7, 14 and 28 days) were evaluated by performing the California bearing ratio tests before and after subjecting the lime-lateritic soil (LLS) samples to continuous leaching using two modified leaching cells. Furthermore, physicochemical analysis was performed to assess the variation of cation concentrations and changes in the physical properties of the pore fluid as the leaching time progressed from 3 to 28 days. The results show that the minimum strength reduction index of the soil corresponds to its lime stabilisation optimum (LSO). Electrical conductivity decreased monotonically and almost uniformly with an increase in leaching time, irrespective of lime content. So, too, was calcium concentration and to a lesser degree for pH and potassium concentration. Adverse changes in the physicochemical behaviour of the LLS samples occurred at lime contents below and slightly above the optimum lime content of the soil. Whereas permanent pozzolanic reactions occurred at lime contents above the LSO and thus resulted in a 45-fold increase in strength and durability. The results are significant for reducing the detrimental effect of the leaching-induced deterioration of flexible pavements founded on tropical floodplains.
01 Nov 1958
TL;DR: Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction.
Abstract: Tropical red soils which occur in the dry flatlands and plains of the eastern Niger Delta Nigeria were evaluated using combined conventional engineering geological investigation with major oxide geochemistry to determine their properties and evaluate their engineering performance in road construction. Laboratory test results indicate that the brownish materials are uniformly graded, silty clayey sandy soils. The silica to sesquoxide ratio values of 3 to 4.37 indicate that they are non-lateritic tropically weathered soils. The average values of the specific gravity, liquid limit, plasticity index and shrinkage limits are 2.67, 37%, 10% and 7.6% respectively. They are soils of low to medium plasticity. The unsoaked and soaked CBR values range from 14-38% and 3-9% respectively whereas the average undrained shear strength is 172kN/m 2 . Maximum dry density and optimum moisture content values fall between 1680 to 1880kN/m 2 and 13-16% respectively. Generally the soils classify as A-7-6 to A-2-4 subgroups of the AASHO classification. The overall implication of these composite engineering properties is that the non-lateritic soils rate as poor to fair subgrade materials.