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F. C. Ugbe

Bio: F. C. Ugbe is an academic researcher. The author has contributed to research in topics: Geology & Geotechnical engineering. The author has an hindex of 1, co-authored 1 publications receiving 13 citations.

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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.

15 citations

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TL;DR: In this paper , the influence of stabilization by percentage increase in volume of cement on Geotechnical properties of some lateritic soils obtained from two borrow pits along Agbor-Sapele road, Western Niger Delta, Nigeria.
Abstract: This study is aimed at determining the influence of stabilization by percentage increase in volume of cement on Geotechnical properties of some lateritic soils obtained from two borrow pits along Agbor-Sapele road, Western Niger Delta, Nigeria. The soils are classified as A-7-6 and A-7-5 with high percentage of Fines, averaging 60.43%. These natural soil samples falls short of the Federal Ministry of Works Standard based on grain size and consistency limits. The values of 1950.91 Kg/m3 and 22.70% obtained for maximum dry density (MDD) and optimum moisture content (OMC) when soil was treated at 10% by volume of cement, reveals the fact that higher unconfined compressive strength (UCS) values would be noticeable at 10% by volume addition of cement with increasing energy level of compaction, than that to be obtained at 5% by volume of addition of cement with MDD of 1933.80 Kg/m3 and OMC 22.78%. When the soaked California Bearing Ratio (CBR) values for treated soils were considered, the reduction in soaked CBR value is minimal at 10%, with an average of 76.33% than that obtained at 5% by volume of cement with an average of 78.45%, compacted at varying energy level. In general, the study result clearly reveals that increasing cement content would result in improved strength characteristics even as permeability decreased from 6.744x10-8 mm/s to 6.129 x 10-8 mm/s across the compaction level of the stabilized soil samples.
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TL;DR: In this article , a total of 10 samples of syenitic rocks were collected for laboratory analyses and the results showed that the syenites are peraluminous in character as shown by the bivariate plots of A/NK vs. A/CNK.
Abstract: Syenites are relatively rare within the Nigerian Basement Complex. As a result of their rarity, these rocks have been given less research attention over time and are consequently poorly understood. The syenitic rocks at Igarra were studied to ascertain their tectonic evolution using geochemistry. Sampling was carried out using the survey-type geological field mapping approach. A total of 10 samples of syenitic rocks were collected for laboratory analyses. Compositionally, the rocks are intermediate with regards to SiO2 content (58.02% – 60.58%), having Al2O3 and alkali (Na2O + K2O) compositional ranges of 15.34% – 15.52% and 8.99% – 9.7% respectively. The sampled rocks are similar and consistent in their trace and rare earth elements concentrations (the only exception being Zr with values ranging from 4 ppm to 79 ppm). The rocks are relatively enriched in Ba, K, TI, and Sr but depleted in Tc, Nb, U, Hf, Yb, Te and Ta. The syenites also show fairly high ratios of Rb/Nb and Rb/Sr with mean values of 488.627 and 0.171 respectively. As seen from the geochemical analyses, the syenites around Igarra are high-K calcalkaline, alkalic to alkalic-calcic. The rocks are peraluminous in character as shown by the bivariate plot of A/NK vs. A/CNK. Sedimentary protolith with continental crustal parent magma is inferred for these rocks. The similarity and consistency of the trends of major, trace and rare earth elements is indicative of cogenetic origin for the rocks. The geochemistry and discrimination plots for the rocks indicate geodynamic setting ranging from orogenic to post-orogenic. A volcanic arc geotectonic setting is interpreted for the Igarra syenites, with magma emplacement and evolution thought to have been initiated during the late stages of the Pan-African reactivation and continued into post-orogenic times.
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TL;DR: In this paper , the utility potential of ferruginised sandstone was investigated to ascertain their utility potential, including the modal composition, texture, packing density, degree of interlocking of grains, specific gravity (SG), water absorption capacity, aggregate crushing, aggregate impact, and Los Angeles abrasion values.
Abstract: The need to reduce the high cost of long-distance haulage of aggregates has necessitated the search for suitable aggregates close to the construction site(s). The petrographic and geotechnical properties of Ogwashi-Asaba ferruginised sandstone were investigated to ascertain their utility potential. The petrographic, physical, and mechanical properties investigated include; the modal composition, texture, packing density, degree of interlocking of grains, specific gravity (SG), water absorption capacity (WAC), aggregate crushing, aggregate impact, and Los Angeles abrasion values. Which were determined according to BS and ASTM standards. The percentage of iron (Fe2O3) was determined by fusion inductively coupled plasma (FUS-ICP). The results show the mean value of quartz as 59.4%, sub-angular to angular shape, medium, medium-coarse, and coarse-grained with sutured, concavo-convex, and long contacts. The mean values for the S.G., WAC, ACU, AIV, and LAAV are 2.68, 4.80%, 53.76%, 41.99%, and 50.12% respectively, and 17.8% for Fe2O3. The medium-grained sandstone is preferred because of its relatively higher quartz percentage, more sutured contacts, and a greater degree of grains interlocking. Fe2O3 in sandstone has a strong negative correlation with AIV and ACV. This implies that Fe2O3 in sandstone will influence strength in sandstone thereby enhancing its utility potential. Though the ferruginised sandstone may be suitable as base course material in high-density traffic roads, it can be utilized as sub-grade and sub-base materials in low-density traffic roads.

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Journal ArticleDOI
TL;DR: In this paper, the authors studied the time-dependent changes in the structure of lime stabilized montmorillonitic and lateritic clays using solid state nuclear magnetic resonance (SS-NMR) and Fourier transform infrared (FTIR) spectroscopy.

119 citations

Journal ArticleDOI
TL;DR: In this article, the authors present results of land cover change analyses, results of an assessment of coastline dynamics, as well as the manifestation of oil exploitation activity as expressed via oil access canal dredging and gas flaring, monitored within the 27 year time span investigated.

90 citations

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TL;DR: In this article, the authors have reported significant concentrations of rare earth elements (REEs) in different geological formations and mineral resources, such as Pulmoddai and other beach placer deposits, Eppawala carbonatite, alluvial placer and pegmatites.

35 citations

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TL;DR: In this article, compaction and strength characteristics test were investigated using three compactive efforts (i.e., British Standard light, BSL (standard Proctor), West African Standard, WAS or ‘intermediate) and British Standard heavy, BSH (modified Proctor).
Abstract: Laboratory studies on lateritic soil treated with up to 8% calcium chloride (CaCl2) by dry weight of soil was carried out to establish the soil improving potential. Tests carried out include Atterberg limits and linear shrinkage, compaction characteristics (maximum dry density, MDD and optimum moisture content, OMC), strength characteristics (unconfined compressive strength, UCS and California bearing ratio, CBR) and microanalysis. Compaction and strength characteristics test were investigated using three compactive efforts [i.e. British Standard light, BSL (standard Proctor), West African Standard, WAS or ‘intermediate’ and British Standard heavy, BSH (modified Proctor)]. Results obtained show that Atterberg limits decreased with increased calcium chloride content. MDD increased with a corresponding decreased OMC of the soil–CaCl2 mixtures for the three compactive efforts. Peak UCS and CBR values were obtained at 4% CaCl2 content with increasing compactive effort. Microanalysis using Scan Electron Microscope, SEM shows the transformation of surface morphology at the edges of clay particles. Statistical analysis of result shows that CaCl2 content had significant influence on the Atterberg limit parameters and both the variations of CaCl2 content and compactive effort had significant effect on the strength parameters, maximum dry density as well as the optimum moisture content. The R2 values of regression models show that CaCl2, LL, MDD, OMC and CE have considerable influence on the UCS at 7 days curing and CBR values. Peak strength values are below those recommended for sub base and base stabilization, hence CaCl2 is not convenient as a stand-alone stabilizer but can be adequate as a modifier or as admixture in Cement or lime stabilization of lateritic soil.

31 citations

Journal ArticleDOI
TL;DR: In this article, the results of various tests conducted on these soils collected from the eastern part of the country and the correlations established between different parameters for easier determination of complex soil properties are presented.
Abstract: Due to the scarcity of crushed stone aggregates, the feasibility of using locally available granular materials and marginal aggregates as pavement material is being explored in most part of the world. Granular lateritic soil (locally known as Moorum) has been used as a sub-base material for road construction in India. The characteristics of lateritic soils vary considerably based on their mineralogical composition, microstructure of soil particles, climate, parent rock and degree of laterisation. Therefore a detailed characterization of granular lateritic soils available locally in India is very much essential for its use as pavement material. In recent years, there is a sway towards mechanistic design of pavements, which requires the mechanical properties of all the materials being used in the pavement layers. Material property in terms of elastic modulus or resilient modulus and Poisson’s ratio are two major input parameters for mechanistic design. Granular materials show stress hardening characteristics and behave non-linearly under repeated loads. Considering the requirement of characterization of granular lateritic soils in India, a comprehensive laboratory study was taken up. This paper presents the results of various tests conducted on these soils collected from the eastern part of the country and the correlations established between different parameters for easier determination of complex soil properties.

25 citations