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Clayey soils exhibit significant volumetric changes in response to variations in water content. The swelling pressure of clayey soils is a critical parameter for evaluating the stability and performance of structures built on them, facilitating the development of appropriate design methodologies and mitigation strategies to ensure their long-term integrity and safety. We present a dataset comprising maximum swelling pressure values from 759 compacted soil samples, compiled from 16 articles published between 1994 and 2022. The dataset is classified into two main groups: 463 samples of natural clays and 296 samples of bentonite and bentonite mixtures, providing data on various types of soils and their properties. Different swelling test methods, including zero swelling, swell consolidation, restrained swell, double oedometer, free swelling, constant volume oedometer, UPC isochoric cell, isochoric oedometer and consolidometer, were employed to measure the maximum swelling pressure. The comprehensive nature of the dataset enhances its applicability for geotechnical projects. The dataset is a valuable resource for understanding the complex interactions between soil properties and swelling behavior, contributing to advancements in soil mechanics and geotechnical engineering. [ABSTRACT FROM AUTHOR]

The role of a landfill liner in the waste management process cannot be overemphasized. They are usually made of clay soils or geosynthetic materials or both with the sole purpose of controlling the migration of leachates into underlying aquifers and soils thereby preventing contamination. The limited availability of clay soils and high cost of geosynthetics have necessitated the search for and use of different locally available materials. Lateritic soils are one of the most commonly used materials for landfill liners in the tropical areas, where they commonly occur. However, a comprehensive review of literature on the utilization of lateritic soils as landfill liners has not been reported. Conducting a systematic review of lateritic soils for landfill liner applications enables an enhanced understanding of their inherent characteristics and appropriateness. This, in turn provides vital insights for the design and construction of effective and economically sustainable waste containment systems. Hence, this paper reviews the nature and characteristics of lateritic soils and assesses their suitability for landfill lining applications through a thorough evaluation of the desirable geotechnical, geological and geochemical properties based on available literature and data. Data on the index and geotechnical characteristics of lateritic soils at two hundred and seventy-eight locations from different countries were collected from literature and assessed based on standard specifications for landfill liners. Furthermore, their leachate attenuation characteristics and improving their suitability for landfill liners through property amendments are presented. The review results indicate that lateritic soils possess suitable engineering properties with some interesting clay mineralogical compositions for lining applications. In addition, the desirable geotechnical properties of lateritic soils can also be improved by blending it with bentonite, fly-ash, sawdust and mine tailings. Although mineralogical transformations occur after permeation with landfill leachates, lateritic soils possess contaminant attenuation characteristics such as low diffusion, good sorption and cation exchange properties that are needed for landfill liner applications. [ABSTRACT FROM AUTHOR]

Clay mixed soil is a combination of clay and soil components that may be used as the core of earth dams and the foundation for building and road construction. Up until now, significant research work has been carried out to design cement-based clay materials; however, only a couple of studies have been reported in the literature on earth-based materials. The methodology portion provides an overview of the different materials, tools, and protocols used during work to develop ways to earth-based materials and study their early age compression strength along with their shear strength. Finally, it summarizes all the results and the outcome of the experimental work done. The probability of producing an object using earth-based material was examined. Improvement in the compressive strength in the early age of strength by adding additives like bentonite and rice husk was assessed in this study. Three clayey soil samples were investigated. The undrained shear strength based on an unconfined compression test (UCT) over those samples was measured by varying the moisture content (MC). After performing all these tests, a relationship was developed between the UCT and vane shear test (VST) undrained shear strengths of the selected soil samples. Clay samples with different mix designs were investigated, and building components were printed out to check the early age shear strength development and printable properties of different mix designs. This study will lay the foundation for further research on different aspects relating to the emerging technology of 3D clay printing in Pakistan. [ABSTRACT FROM AUTHOR]

Due to the increase in population, the demand for buildings increases. The engineering properties of the soils on which these structures will be built may not always meet the desired conditions. In such cases, soil improvement methods are used. One of these methods is additive used stabilization, in which additives such as lime, fly ash, volcanic ash and tuff, silica fume, and blast furnace slag are used. This method has been used successfully for years. However, in recent years, interest in the use of different types of fibers has increased. Some of these fibers are glass, basalt, polypropylene, and carbon. Basalt fibers have begun to attract attention in soil reinforcement applications due to the properties of their raw material, basalt rock, which is widely distributed in nature, natural, and has high strength. In this study, the effect of basalt fiber reinforcement on the unconfined compressive strength of high plasticity bentonite clay was revealed. For this purpose, 12 mm long basalt fiber in different proportions (1%, 2%, 3%, 4%, and 5%) was used as reinforcement in bentonite clay, and the optimum fiber ratio that provided the maximum increase in strength was determined. According to the results of the study, when 12 mm long basalt fiber was used as reinforcement in bentonite clay, the maximum strength value was obtained at a 4% basalt fiber ratio. However, the strength value decreased in the sample where 5% BF was used. It has been determined that basalt fiber reinforcement improves the strength properties of bentonite clay. [ABSTRACT FROM AUTHOR]

Excessive levels of phosphate in stormwater runoff can negatively impact receiving surface water bodies, such as retention ponds, and may also seep into groundwater. Liner systems composed of materials with greater phosphate selectivity have the potential to mitigate infiltration and eliminate phosphate. One potential material is chitosan, an abundant naturally occurring biopolymer. This study evaluated five materials for their ability to remove phosphate from synthetic stormwater using batch tests with different initial phosphate concentrations ranging from 0.5 to 12 mg/L and a fixed 24-h exposure time. The materials included two types of clayey soils (kaolin and bentonite) and three different varieties of chitosan with varying molecular weights (low, medium, and high). The phosphate removal efficiency of kaolin was found to be the highest, with efficiencies ranging from 100% to 56% at different concentrations, while bentonite was found to be the least effective, with removal efficiencies ranging from 40% to 12%. The removal efficiencies of all three types of chitosans analyzed were higher than those of bentonite but lower than those of kaolin. The removal efficiencies ranged from 77% to 19% for low-molecular-weight chitosan, 84% to 31% for medium-molecular-weight chitosan, and 55% to 18% for high-molecular-weight chitosan. The removal mechanism of phosphate by kaolin and bentonite was attributed to surface adsorption and precipitation. In chitosan, the likely mechanism is electrostatic attraction. The maximum adsorption capacity for kaolin was not reached under the tested phosphate concentration range, indicating potential adsorption sites remained available on the particle surfaces. The results for bentonite, low-molecular-weight chitosan, and high-molecular-weight chitosan showed that these materials nearly reached their maximum adsorption capacities, indicating that fewer adsorption sites were remaining. The Langmuir adsorption isotherm was found to be the best-fit model for phosphate adsorption in all the materials tested compared to the Freundlich isotherm. According to the Langmuir model, the maximum adsorption capacities for kaolin, bentonite, low-molecular-weight chitosan, medium-molecular-weight chitosan, and high-molecular-weight chitosan were found to be 140.85, 33, 48.78, 82.64, and 51.28 mg/kg, respectively. [ABSTRACT FROM AUTHOR]

In recent years, there has been an increasing interest in investigating the use of non-traditional additives for stabilizing problematic soils. As the demand for eco-friendly alternatives to cement rises, magnesium chloride, a widely used deicer and dust suppressor, has emerged as a potential choice. This study aims to provide a comprehensive understanding of the microstructural changes that occur and affect the macro behavior of treated bentonite (B) and yellow marl (YM). To achieve this, MgCl 2 solution was added to the soils at 3, 6, 9, and 12 percent by dry weight of the soil, and samples were cured for 7, 14, and 28 days at 5° C , 25° C , and 35° C. The mechanical properties of the treated soils were then evaluated using the unconfined compression test, direct shear test, and pressure chamber test (SWCC), while microstructural analysis techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDAX), and Fourier transform infrared spectroscopy (FTIR) were employed to examine the mechanism of MgCl 2 stabilization. The results indicate that adding MgCl 2 and extending the curing period significantly increased both soils' unconfined compressive strength (UCS). However, the UCS value decreased for treated samples cured at temperatures higher than 25°C due to an incomplete cation exchange process and the reduction of apparent cohesion. A part of the gained strength from apparent cohesion and matric suction in the unsaturated samples was lost when the samples reached full saturation during the direct shear test. Changes in the particle size, pore size, and pore void distribution due to the MgCl 2 stabilization affected the SWCCs of the treated soils. Microstructural analyses revealed the formation of magnesium hydration products, such as magnesium silicate hydrate (M-S-H) and magnesium aluminate hydrate (M-A-H), which contributed to the strength increase by increasing grain size, filling the pores, binding fine particles within coarse grains, and forming a flocculated structure through recrystallization of MgCl 2 and the formation of cementitious gel. Additionally, for B, adding MgCl 2 led to soil flocculation through ion exchange, while for YM, the same process occurred due to the greater surface tension of the saline solution encircling the particles. • Microstructural analyses indicated the production of cementitious hydration products M-S-H and M-A-H. • Increasing curing temperature reduced the strength by decreasing the apparent cohesion. • The treatment of the B and YM with MgCl 2 decreased the LL and PI. • Stabilized soil structure changed to a flocculated, interlocked, and denser one. • UCS of both soils improved up to 110 % due to recrystallization and cementation of MgCl 2. [ABSTRACT FROM AUTHOR]