Lateritic Clay Soil Research Articles

Performance of Bitumen Emulsion Mixtures utilized as Gravel Road Base incorporating Lateritic Clay Soil and Calcined Sugarcane Bagasse Ash Filler

Performance of Bitumen Emulsion Mixtures utilized as Gravel Road Base incorporating Lateritic Clay Soil and Calcined Sugarcane Bagasse Ash Filler

Construction of multi-purpose geophysical test site on a lateritic clay soil

Construction of multi-purpose geophysical test site on a lateritic clay soil

Enhancing Geotechnical Properties of Lateritic Clay with Sawdust Ash-Lime Stabilizer

One important means of refining the geotechnical characteristics of soils is stabilization. This research sought to improve the geotechnical properties of lateritic clayey soil using sawdust ash-lime (SDAL) stabilizer. Soil-SDAL mixtures were made, after collecting lateritic clay samples and preparing mixtures of lime and sawdust ash in a ratio of 1:2. SDAL mixtures were added to the lateritic clay in increasing percentages from 0 to 10%. The materials’ index properties were determined, and compaction of the Soil-SDAL mixtures was done using four compactive efforts namely Reduced British Standard Light (RBSL), Standard Proctor (SP), West African Standard (WAS), and Modified Proctor (MP). Unconfined compressive strength (UCS) tests were performed on the Soil-SDAL mixtures as well. Results of the tests showed that the soil could be classified as an A-7-5(7) soil with a 13.7% plasticity index. The plasticity index increased with the addition of SDAL mixtures up to 6% after which there was a gradual decline. Meanwhile, maximum dry density (MDD) decreased while optimum moisture content (OMC) increased with SDAL addition. Unconfined compressive strength (UCS) of the soil increased from 38.58kN/m2 at 0% SDAL to a maximum of 129.63kN/m2 at 6% SDAL, after which there was a gradual decrease. Similar trends were noticed at all compactive efforts, indicating consistency in the performance of the stabilizer. Optimum results were achieved at 6% SDAL content, with Modified Proctor compactive effort giving the maximum value of 1,860kg/m3 MDD. The results prove that sawdust ash-lime mixture offers tremendous abilities in improving lateritic clay soil properties.

Evaluation of the incorporation of construction waste (CW) for the stabilization of soil-cement mixtures

Abstract The reuse of construction waste (CW) has been increasingly adopted as a way to reduce the environmental impact from inadequate disposal of this material worldwide. The stabilization of soils with cement is a common practice, enabling the use of this material in a variety of projects. However, depending on the type of soil, frequently large quantities of cement are needed, making the technique impracticable. The use of CW in the soil stabilization process may be an alternative for reducing the amount of cement and improving the strength of the mixture. The objective of this work was to investigate the use of CW to partially replace a lateritic clay soil in soil-cement mixtures. Besides the natural soil (S), a mixture of soil and CW (S-CW) was used with proportions of 50% of each. The cement content levels evaluated were 0%, 4%, 6% and 8% and the curing periods varied from 7 to 28 days. The results showed superior strength values for the S-CW compared to the soil-cement. This confirms that the use of CW reduces the percentage of cement necessary for the stabilization of a clayey soil and presents an alternative, more environmentally appropriate destination for this material.

Comparison of Compressibility Behaviour of Lime-Cement Stabilized Lateritic Clay Soil Contaminated by Heavy Metals

The type of stabilizer, heavy metal and soil can typically affect the strength and compressibility development in the treatment of contaminated soils. This is due to the difference in chemical reactions and interferences occurring among the stabilizers, metals, and clay minerals. A standard consolidation test using an oedometer was carried out to investigate the cement–lime induced changes in the compressibility of clay soils contaminated with either copper or zinc. In this study, laterite clay soil obtained from the hilly area at Universiti Teknologi Malaysia was used. Control samples of cement-and lime-stabilized soils without heavy metals were compared with the treated contaminated stabilized soil at various contaminants contents. Such percentage of contaminants means that the soil falls under industrially contaminated soil. To highlight the effect of the two heavy metals on the consolidation behavior of clay samples treated with cement and lime, a comparison has been made at a curing period of 7, 28, 100, and 200 days respectively. It was found that the interference of heavy metals during the process of hydration (cement and lime) contributed directly to the inhibition of the compression development of the tested soil samples. Therefore, it is crucial to identify the type of stabilizer, heavy metal, and soil involved to ensure successfully and remediate treatment.

Nigerian Lateritic Clay Soils As Hydraulic Barriers To Adsorb Metals. Geotechnical Characterization And Chemical Compatibility

The suitability of using lateritic clays from Aviele and Igarra has been investigated both in the Northern part of Edo state, Nigeria as liners of an engineered landfill and to adsorb metals in leachates. Geotechnical characteristics, pH, and elemental composition for the lateritic clay samples were determined. The chemical composition, pH, total dissolved solids and electrical conductivity were determined for leachates collected from two dumpsites. The capacities of the lateritic clay soils to adsorb heavy metals in the leachates were determined using the batch equilibrium adsorption technique. The unconfined compressive strength (UCS) of soils were found to be sufficient to resist damage. By both the standard and modified Proctor compaction tests, it was found that the coefficients of permeability for the soil samples were lower than 1×10–9 m/s that is widely recommended for soils that are to be used as landfill liners. Pb2+, Zn2+ and Cr2+ were the heavy metals in the leachates. The sorption selectivity order for tested soils depended on the soil type and properties.

English

For the first time, natural seed germination in cultivated population of Cassia fistula Linn. is reported in this paper. Natural seed germination occurred under many mother trees at Covenant University, Ota, Ogun State, Nigeria; while no germination occurred under some other mother trees. Random soil samples were taken in representative areas and analysed. Seedling dynamics were also investigated by fencing the seedlings around five mother trees, mapping and following their survival with time. Soil samples obtained where there was germination are loose, black soils with high moisture and humus contents and mean pH of 7.2 while soil samples obtained where there was no germination are hard, red lateritic clay soils with significantly lower moisture and humus contents and mean pH of 6.4. The seedlings study showed that some seedlings were more or less in a straight line from broken and rotted pods buried in the soil or covered in debris. Other seedlings were single, in pairs or in groups of three or four. A seed germinated within a pod and grew out of a small hole in the pod, with the radicle coming out first and by the next day, the cotyledons emerged. In the first few weeks of study, the number of seedlings in each fenced area increased with time, thereafter the number decreased accompanied by yellowing of leaves. There was also increased growth of surrounding weeds mainly grasses, as well as about 60% reduction in light intensity on the seedling floor due to the development of new foliage on the mother trees. The reduced number of seedlings under the mother trees was attributed to increased inter specific competition as well as reduced light intensity reaching the seedlings since C. fistula is not shade tolerant. Consequently, cultivated C. fistula like the natural population may not regenerate well in nature and its continued existence may depend on artificial conservation through its use as ornamental and medicinal plant.   Key words: Natural germination, seedling dynamics, cultivated population, Cassia fistula, Nigeria.

Effects of Soldier-Ant Mound (SAM) on the Strength Characteristics of Lateritic Clay Soils

The aim of this work is to i nvestigate the effect of Soldier -Ant Mound (SAM) on the strength characteristics of lateritic clay soils in order to improve their poor geotechnical properties for road pavement construction. Three soil samples were collected from a burrow pit along the La gos-Ibadan Expressway, Lagos, Nigeria. The samples were mixed with Soldier-Ant Mound in various proportions (0%, 2%, 4%, 6%, 8% and10% by weight) and subjected to soil strength tests: Compaction tests, California Bearing Ratio (CBR) and Unconfined Compressive Strength tests at the University of Lagos, Nigeria between June 2012 and July 2013. Results obtained were compared with the natural soil and standard values. The Atomic Absorption Spectroscopy, AAS, gave the exchangeable cations present in the Soldier -Ant Mound as: Calcium (Ca 2+

Lime Stabilization of Tropical Soils From Sudan For Road Construction

The objective of this paper is to study the effects of hydrated lime on the engineering properties of interest for road design and construction for three tropical clays, two highly plastic potentially expansive soils from Republic of Sudan and one red tropical “lateritic” soil from Republic of South Sudan. The studied properties include Atterberg limits, compaction parameters, permeability, CBR, MR and unconfined strength. The effects of compaction energy on the end result compaction material property parameters were studied. Also, the effect of salinity/sodicity on the plasticity and strength of lime stabilized swelling soils was studied. The study showed that lime efficiently reduces the plasticity of the three soils considered and that for the same increment of lime content the reduction in plasticity is higher for montmorillonitic clays compared to kaolinitic clays. The addition of lime to the three soils increased their maximum dry density and reduced their optimum moisture content. Substantial improvement in the strength and compaction characteristics of lime stabilized tropical clays could be expected on increasing the compaction effort. Permeability substantially increased on adding the optimum lime content to the three soils. Lime increased the strength and stiffness of the treated soils and the amount of lime needed to improve lateritic clay soils is less than that needed to improve swelling soils. The MR test results indicate increased stiffness of the lime stabilized kaolinitic clay soils compared to montmorillonitic clays. The increase in salinity/sodicity resulted in decrease of plasticity and increase in strength for the natural untreated and lime treated sodic soil tested.

The assessment of structure in tropical soils

A comparison of methods of measuring the structural condition of cultivated surface soil was made for two important East African soil types.The soil samples were drawn from two field experiments: (i) a tillage trial in coffee on a porous red lateritic clay soil of recent volcanic origin; (ii) a rotation trial for cotton, on a red sandy lateritic loam of granitic origin.Of the measurements on soil cores, total porespace and field capacity (⅓ atmosphere) showed little change, while percolation rates, free-draining pore-space and a new rainfall acceptance test all reflected the observed field behaviour of the soils, and showed fairly close and highly significant correlation. Field sieving of dry clods gave highly significant differences in the lateritic clay, the stronger clods indicating the poorer soil condition. Drysieving for ½ mm. crumb was ineffective, as was wet-sieving after wetting under vacuum. Wetting by immersion gave some differences between treatments, but higher variability and no significant correlation with free-draining pore-space. Wetting by rainfall impact on dry crumbs gave the best wet-sieving tests on the clay soil. Different sieving techniques gave inconsistent results on the sandy soil. Crumb structure measurements are not efficient indications of structural conditions on these soil types, which are of wide occurrence in tropical countries.