Lateritic Research Articles

Effects of Palm Kernel Shells (PKS) on Mechanical and Physical Properties of Fine Lateritic Soils Developed on Basalt in Bangangté (West Cameroon): Significance for Pavement Application

The utilization of an agricultural waste product known as palm kernel shells (PKS) combined with fine laterites (from basalt in Bangangté, West Cameroon) to produce low-cost and innovative materials with good bearing capacities for road pavement was investigated. Fine laterites from two soil profiles (BL31 and BL32) and made up of kaolinite, hematite, goethite, gibbsite, anatase, ilmenite and magnetite minerals were partially replaced with PKS at 15%, 25%, 35%, and 45% by weight. Physical and mechanical tests, including particle size distribution, Atterberg limits, unsoaked and soaked California Bearing Ratio (UCBR and SCBR), unconfined compressive strength (UCS), and tensile strength (Rt), were performed on the different mixtures. After the addition of PKS, a decrease in fine particle content (77 to 38%), liquidity limit (LL: 72 to 61%), plasticity index (PI: 30 to 19%), maximum dry density (MDD: 1.685 to 1.29 t/m3), and optimum moisture content (OMC: 27.5 to 24.0%) was noticed. Additionally, there was an increase in UCBR (16–72%), SCBR (14–66%), UCS (1.07–7.67 MPa), and Rt (2.24–9.71 MPa). This allows new materials suitable for the construction of base layers for low trafficked roads (T1–T2), as well as sub-base and base layers for high trafficked roads (T3), to be obtained. This newly formed material can be recommended locally for road construction works, though more in-depth studies are required.

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

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

Engineering Evaluation of Laterite Derived from Sedimentary Rock for Use as Subgrade and Sub-Base Materials

Geotechnical assessment of lateritic soils obtained from along the Ojota and Shagamu ends of the Lagos–Ibadan expressway was conducted to evaluate their suitability for use as sub-grade and sub-base materials. Laboratory tests, including moisture content, specific gravity, particle size distribution, fabric/plasticity, compaction, and California Bearing Ratio (CBR), were performed on eight (8) soil samples following British Standards (BS) 1377 methods for soil testing. The lateritic soils were classified as clayey sand, silty clay, and silty to clayey sand. They exhibited moderate plasticity and semi-pervious characteristics, suggesting suitability for use as sub-grade materials. Samples 3, 5, 7, and 8 were identified as more suitable for road construction materials, while Samples 1, 2, 4, and 6 showed susceptibility to seasonal volume changes due to high clay content. These samples would require minor soil stabilization to mitigate the effects of their active clay contents. Adequate drainage systems were recommended to prevent water accumulation, soil volume changes, loss of load-bearing capacity, and potential material failure beneath road pavements. The geotechnical properties of the lateritic soils from the tropical area of Ojota–Shagamu differed significantly from those of other lateritic soils found in southwestern Nigeria.

Geotechnical Assessment of Selected Lateritic Soils in Southwest Nigeria for Road Construction and Development of Artificial Neural Network Mathematical Based Model for Prediction of the California Bearing Ratio

Investigation of the geotechnical characteristics of eighteen different lateritic soils within southwest Nigeria was carried out to determine their suitability for road construction. To achieve this goal, the lateritic soils samples were subjected to different laboratory tests, including specific gravity, Atterberg limits, grain size analysis, California bearing ratio, and compaction, in accordance with the ASTM standard procedure. The results of the tests showed that the specific gravity varied between 2.55 and 2.81; the linear shrinkage varied between 6.68% and 10.98%; the liquid limit varied between 37.17% and 56.93%; the plastic limit ranged from 19.47% to 37.14%; the plasticity index ranged from 3.81% to 30.29%; the fine sand content ranged from 37.07% to 62..93%; the fines content ranged from 36.4% to 60.9%; the maximum dry density ranged from 1747 kg/m3 to 2056 kg/m3 ; the optimum moisture content ranges from 10.94% to 20.51%; the un-soaked California bearing ratio ranged from 14.7% to 45.6%; and the soaked California bearing ratio ranged from 10% to 31%. Based on these results, all the studied soils can be used as road subgrade, while none except Loc.5/S1 is suitable for road subbase. However, none of the soils meets up with the requirement for road base course. The suitability of laterite for the construction of road depends largely on the California bearing ratio. However, laboratory tests for determining the California bearing ratio is tedious, time consuming and costly. As a result of this difficulty, there is a need to develop soft computing models to predict laterite California bearing ratio from index properties with cheap and simple tests. Thus, the experimental datasets of the eighteen studied lateritic soils were used to create and train artificial neural network (ANN) models to predict California bearing ratio from liquid limits, plasticity index, linear shrinkage, fine sand content and fines content. The proposed ANN models were compared with the multiple linear regression models proposed in this study and various regression based models suggested in the literature via statistical analyses. Based on the model comparison, the proposed ANN models outperformed the rest of the models; they presented the highest R 2 and the lowest RMSE, MAPE and MAE values. Thus, the ANN models are validated. To enhance the practical application of the proposed ANN models, they were transformed into simple mathematical equations, which gave the same predictions as the direct ANN models. Thus, they can be used for practical purposes.

NON-FIRED LATERITE SOIL BRICKS WITH NA-BASED STABILIZER ADDITION FOR SUSTAINABLE DEVELOPMENT

Fired bricks are widely used, but they are energy-intensive and non-eco-friendly. Non-fired bricks with chemical stabilisers can be the alternative solution, which is a low-energy-intensive and environmentally friendly manufacturing product. Laterite soil can be the raw material for the synthesis of non-fired clay brick in sodium hydroxide solution and sodium silicate solution. However, it may have been mixed with other laterite soils with different optimum moisture contents and grain sizes during extraction. Thus, the mixing ratio of laterite soil, Na-based stabilisers, and water for non-fired brick production is determined. Besides, two types of laterite soil, LAT 1 and LAT 2, from different locations were prepared, and another type of laterite soil, LAT 3, was prepared by mixing LAT 1 and LAT 2. Both three are compared primarily in terms of compressive strength and water absorption, which are mixed with the Na2SiO3/NaOH ratio. As a result, the new mixing ratio with increased water content was determined based on the optimum moisture content of the soil. Besides, the optimum mixing ratio of each type of brick was determined. Overall, based on the Malaysian standard, all types of brick samples from each ratio could be used as load-bearing class 1 and internal wall bricks. Additionally, LAT 2 and LAT 3-based bricks with a ratio of 1.5 Na2SiO3/NaOH ratio can be used as load-bearing brick class 2.

Soil health and sugarcane productivity management through integrated nutrient management by using different organic manure sources and planting geometries in lateritic soils of Konkan region of Maharashtra

Soil health and sugarcane productivity management through integrated nutrient management by using different organic manure sources and planting geometries in lateritic soils of Konkan region of Maharashtra

Strength behaviour of soil blended with two waste materials-fly ash and tire crumbs with cement

Abstract The rapid development in the economy has led to a growing need for electricity and automobiles, leading to the production of large quantities of fly ash (FA) and discarded tires. The safe disposal of these materials has become a significant problem. FA and scrap tyre derived material has some useful properties which can be beneficially used for enhancing the engineering properties of soil. Therefore, the study investigates the combined impact of FA and scrap tire-derived material on the stress-strain-strength behaviour of a fine-grained residual lateritic soil, incorporating a cementing agent. The research involves compaction tests followed by triaxial compression tests, where FA content added at an increment of 15% starting from 20% by weight of soil. The maximum FA content used in the mix is 50% by weight of soil. Tyre crumb (TC) which is a scrap tire-derived material, is also included in the study, with TC content ranging from 5% to 10% by weight. Additionally, 2% by weight of cement is added to each soil mix as a binding agent. Specimens are compacted in accordance with specific compaction parameters and subsequently cured for duration of up to 28 days. Strength tests are then carried out on those specimens to analyse their strength behaviour. This research primarily examines the shear strength characteristics of soil blended with FA, cement, and TC, emphasizing their geotechnical performance. Addition of 5% TC increases the peak deviator stress of cemented mix having 50% FA content from 1351 kPa to 2710 kPa at 300 kPa confining pressure and 28 days curing period. The inclusion of TC to soil-FA-cement blends is noted to significantly enhance shear strength when compared to mixes without tire crumb. Also, the stress-strain behaviour of soil is significantly influenced by addition of FA and cement in the presence of TC. Therefore, there is an ample scope of utilization of soil-fly ash-cement-TC mixes in geotechnical applications.

Performance evaluation of laterite soil embankment stabilized with bottom ash, coir fiber, and lime

Performance evaluation of laterite soil embankment stabilized with bottom ash, coir fiber, and lime

Using Soil Magnetic Susceptibility Proxies to Estimate Overburden Thickness Overlying Ore of Lateritic Soils in Sulawesi Island Indonesia

Sulawesi Island is one of the largest Ni ore producers in Indonesia. It is also expected to be a significant potential source of some critical metals (e.g., Co, Sc, rare-earth elements, and platinum-group elements). However, few studies show the post-mining impact on some heavy metal elements concentrated in this area. Therefore, improving the efficiency and effectiveness of soil organization and its effect on soil reclamation after mining is helpful. This study aimed to determine the accuracy in estimating the thickness of the overburden covering the nickel ore body profile from lateritic nickel post-mining areas by magnetic susceptibility measurements to discrepancy the overall laterite horizon, whereas χLF and χFD are used to distinguish the overburden zona and limonite and saprolite zone. The lateritic profile studied consists of soil formation of Fe-rich material in the Morowali, and Pomalaa block. We also evaluated the chemical element content of the soil and understood the relationship between the magnetic and geochemical properties of the soil. This study reveals the superparamagnetic (SP)-enriched soils indicated with the increase of the FD% values into the upward horizon, where the maximum values of FD are generally found at ranges 1 to 4m, indicating the overburden layers. Meanwhile, in the depth of 4m to 6m, the values of FD vary only slightly in the lower part initiated by the limonite layers, and then > 6m decreases sharply to the bottom, indicating the saprolite layers. The chemical element mobility trends indicate that Fe, Co, Cr, Mn, and Ti increase toward the layers, which is the same pattern as in FD. Due to this, parameters magnetics may also be a new geophysical approach for estimating the distribution of economically valued minerals on lateritic soils. The strong correlation of Co with Fe, Mn, and Cr in all layers indicates the influence of weathering o n these ultramafic rocks. This suggests an increasing trend toward prolonged pedogenesis.

Combined Effect of the Microstructure and Mechanical Behavior of Lateritic Soils in the Instability of a Road Cut Slope in Rwanda

A very common hazard in Rwanda is represented by the instability of steep road cut slopes in lateritic soil. In its natural state, this material appears as a fine-grained weak and altered rock, generally in unsaturated conditions. Steep cut slopes made by this material could remain stable for a long time unless weathering weakens its mechanical behavior and heavy rainfall provokes a rapid landslide. This paper presents the results of an experimental investigation on the microstructural, petrophysical, and geotechnical properties of lateritic soil from a road cut slope located in Kabaya (Ngororero District—Rwanda), which was recently subjected to a landslide. The mechanical properties of the material are strictly related to the geological origin and history of the deposits, their formation environment, and weathering processes. These characteristics were revealed by peculiar microstructural features (micro-texture, porosity, and degree of alteration of original mineral paragenesis). The experimental investigations included identification and classification tests, direct shear tests on saturated samples, and swelling tests. This multidisciplinary approach provided insights into the relationship between geotechnical properties and the microstructural, petrophysical, and chemical characteristics of the altered rocks. This study showed how different levels of chemical alteration operated by weathering processes, in conjunction with brittle deformation related to the tectonic history, formed in the same site two shallow rock layers with similar macro-scale features and mechanical behaviors but markedly different microstructural and chemical properties. The innovative aspect of this research suggests an integrated multidisciplinary approach to considering microstructural aspects in addition to mechanical behavior in the slope stability analyses in lateritic soil. In particular, this study demonstrates the importance of such an approach since the failure mechanism is better explained if it is based on microstructural observations instead of considering the soil shear strength parameters only. This research helped to explain the formation of the landslide failure mechanism in a specific road cut slope, which could be assumed as representative of many other similar slopes subjected to landslides in Rwanda.

Diffusion of Municipal Waste Pollutants in Electrokinetic Lead Remediated Compacted Lateritic Soil

Diffusion of Municipal Waste Pollutants in Electrokinetic Lead Remediated Compacted Lateritic Soil

Grounding Performance of Hydrogel, Silica Gel and Charcoal Ash as Additive Material in Grounding System

Grounding enhancement materials (GEMs) are one of the additive materials which can change the grounding performance without lots of significant costs. The study aimed to assess the performance of laterite and peat soil, copper and galvanized conductors, and determine the effectiveness of additional materials in reducing grounding resistance. Altering soil characteristics can enhance the conductor's contact area, achieving lower grounding resistance without high costs. Hydrogel, silica gel, and charcoal ash were mixed with soil for testing. Grounding resistance values were measured and collected using the Fall-of-Potential Method using Kyoritsu Earth-Tester-Model-4102. The number of GEMs used were 300g and 600g. Hydrogel, silica gel, and charcoal ash added to soil reduced grounding resistance. Among the various Ground Enhancement Materials (GEMs) tested, hydrogel exhibited the most impressive performance, boasting the lowest grounding resistance at just 56% compared to the reference grounding system. Silica gel followed closely as the second-best performer, with an average grounding resistance of 77% relative to the reference system and lastly is charcoal ash with an average grounding resistance of 77% relative to the reference system. These GEMs significantly enhanced soil conductivity. Furthermore, when considering different soil types and conductor materials, it was observed that peat soil combined with galvanized conductors achieved notably lower grounding resistance in comparison to laterite soil and copper conductors, respectively.

Feasibility of production fired bricks based lateritic soil at very low temperature

AbstractThe present project deals with the production of lateritic soil based bricks under different curing temperatures (28°C–150°C). A fraction of 10–30 wt% amount alkaline solution was added to improve the reactive phase content. The raw materials and hardened products were characterized using X‐ray diffraction (XRD), fourrier transform infrared spectroscopy (FTIR), mechanical properties and scanning electron microscope analysis. The results show that the addition of alkaline solution (30%) and the curing temperature (150°C) have a beneficial influence on physical properties (bulk density: 1.77 g/cm3, water absorption: 16.98%, and porosity: 30.13%) and mechanical performances (flexural: 6.61 MPa and compressive: 13.57 MPa). Compared with the code requirements for stabilized earth blocks, the compressive strength was higher than the minimum required. Microstructural investigations were also carried out to confirm the macrostructural properties. The above‐mentioned process appears to be a suitable candidate for engineering applications such as the stabilization of earth roads.

Soil drives humus formation during composition of wheat straw and cattle manure

Humus formation in compost is key to improving the quality of organic fertilizers. Soil has the potential to promote humus formation due to characteristics such as porousness and large amounts of nutrients, but the mechanisms by which soil drives humus formation are unknown. The study intended to reveal the effects of soil addition on humification and microbial metabolism during composting and to investigate the mechanisms by which soil drives humification. The results showed that hemicellulose and cellulose contents were reduced by 4.67, 11.8 % and 5.85, 6.26 % in compost with Paddy soil (PS) and Laterite soil (LS) addition, respectively, compared to control group. Humus and humic acid increased by 38.1, 38.8 % and 60.6, 77.8 % after composting. Soil addition significantly enriched the hydrolytic bacteria Corynebacterium and fungi Thermomyces, raising the efficiency of organic matter conversion and symbiotic metabolic network complexity. Soil addition improved carbohydrate and amino acid metabolism, facilitating polyphenol synthesis and amino acids polymerization, and enhanced the humus through the polyphenol humification pathway. In summary, by regulating the microbial metabolism during composting, soil can successfully encourage humus formation. This study offers a new option and method for quick humification.

Effect of Scrap Tyre Crumb Rubber (STCR) and Lime on the California Bearing Ratio (CBR) of Non-Lateritic Soil

Nigeria is one of the countries generating many used tyres with only small quantity utilized for different local use and the remaining large quantity dumped in different areas as waste. In this study non – laterite soil was stabilized with 3 % Scrap Tyre Crumb Rubber (STCR) and 5.0, 7.5, 10.0, 12.5 and 15.0 % lime for use as road construction material. Atterberg limit tests, compaction (using West African Standard energy) and California Bearing Ratio (CBR) tests were carried out using standard methods, on the natural non-lateritic soil and the treated soil specimens. Preliminary test on the soil was carried out which classified the soil as A-6 (9) and CL in accordance with ASHTO and USCS classification systems respectively. Compaction and California Bearing Ratio (CBR) parameters of the treated non-lateritic showed a great improvement as the MDD increased from 1.68 Mg/m3 to 1.88 Mg/m3 while the OMC reduced from 17.1 % to 14 %. Both soaked and unsoaked CBR values equally increased to 109 % and 103 % respectively with the addition of lime up to 15% plus 3% STCR waste. Based on results obtained from the study, the use of a mixture of 15% lime and 3% STCR waste, are recommended for the treatment of non-lateritic soil for road construction purposes.

Stabilization of Weak Lateritic Soil with Sawdust Ash and Lime

Stabilization of Weak Lateritic Soil with Sawdust Ash and Lime

Seasonal hypoxia enhances sediment iron-bound phosphorus release in a subtropical river reservoir

Dams worldwide commonly accelerate the eutrophication of reservoirs. While the seasonal hypoxia in deep reservoirs is widely acknowledged, there is limited research on its impact on benthic phosphorus (P) cycling and P fraction release from the reservoir sediments. Here we show that seasonal hypoxia enhances sediment P release and P fluxes at the sediment-water interface (SWI) which might alter P dynamics in deep reservoirs. We conducted a detailed measurement of sediment P fractions through the SEDEX approach, combined with a labile P gradient analysis using the diffusive gradients in thin films (DGT) technique to understand P cycling patterns in sediments during the transition period from spring (oxic) to late summer (hypoxic) conditions. The sediment P pool was predominantly composed of iron-bound phosphorus (Fe−P, 76–80 %), primarily due to the widespread occurrence of lateritic red soil (rich in Fe2O3/MnO2) in subtropical areas. More organic-P was observed in summer compared to spring. A significant increase in labile P occurred at the depth of 0–4 cm and 0–1 cm in spring and summer, respectively, where sediment P release was primarily governed by the reduction of Fe−P and the generation of S2−. A higher apparent fluxes of phosphate across the SWI were observed in summer characterized by higher temperature and lower oxygen levels. The current results suggest that seasonal hypoxia was a crucial factor affecting P cycling and diffusion in deep reservoirs. These findings present important implications for the ecology and management of the watershed-coast ecosystem.

Enhancing Weak Laterite Soil for Road Foundations Using Metakaolin–Bischofite-Alkalinization Additives: Mechanical and Microstructural Characterization

Enhancing Weak Laterite Soil for Road Foundations Using Metakaolin–Bischofite-Alkalinization Additives: Mechanical and Microstructural Characterization

Investigation of rainfall-induced landslide on unsaturated lateritic residual soil slope in Nilgiris, Western Ghats, India using deterministic and reliability analysis

Investigation of rainfall-induced landslide on unsaturated lateritic residual soil slope in Nilgiris, Western Ghats, India using deterministic and reliability analysis

Use of Paper Ash and Lime as a Sustainable Stabilized Materials for Lateritic Soil

This research investigates the effectiveness of paper ash and lime for stabilizing lateritic soils in road construction applications. We assessed varying concentrations of paper ash and lime (0%, 3%, 6%, and 9%) to evaluate their effectiveness for soil stabilization. Initial analyses, including grain size distribution through wet sieving, specific gravity, moisture content, and Atterberg limits, were conducted to classify the soil. Following this, strength and compaction tests utilized standard proctor compactive energy, a method well-suited for field application. The findings indicated a general reduction in Atterberg limits (liquid limit, plastic limit, and plasticity index), an increase in maximum dry density (MDD), and a decrease in optimum moisture content (OMC) with increased concentrations of paper ash and lime. A thorough analysis of the results, along with a comparison to established standards, demonstrated significant improvements in soil properties. Specifically, the study found that 6% paper ash provided optimal stabilization, while 9% lime was effective as a stabilizing agent. These materials are suitable for use in the construction of subgrades and subbases for roads, aligning with AASHTO standards.