Mousa Attom

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This study presents an experimental investigation into the effects of subsurface kerosene contamination on the behavior of model piles in clay. Three instrument piles were placed in a compacted clay bed and tested in three saturations in a two-week period: natural moisture content, water-saturated, and kerosene-flooded. The tests performed on the piles were axial compression and pullout tests, supported by unconfined compression and consolidation tests for the clay. The saturating fluid controls the pile capacity, with the water-saturated condition producing the lowest ultimate capacity and the natural condition the highest. Moreover, it was shown that kerosene contamination significantly modified the mechanical characteristics of the clay, thus leading to an order of magnitude increase in the pre-consolidation pressure and a decrease in the compression index by 50% compared to the water-saturated cases. Under pullout loading, the unit skin friction varied linearly with depth, and failure consistently occurred at the pile–soil interface. This demonstrates the applicability of geotechnical design that considers hydrocarbon contamination to significantly decrease pile capacity and substantially change the consolidation characteristics of clayey soils.

This study presents a sustainable and time-efficient method for producing aerated lightweight concrete (ALC) by addressing two key challenges: long drying times and limited high-silica sand. The proposed approach combines rapid drying, reducing curing time from 24–48 h to less than one hour, with recycled glass powder to enrich locally available silica-poor sand. The concrete mixtures were characterized using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS), along with experimentally determined key parameters such as compressive strength, dry density, porosity, and thermal conductivity. Comparative testing was conducted using sand samples from the UAE and UK to represent contrasting climatic and geological conditions, silica-poor desert versus silica-rich quartz, to evaluate adaptability and performance. Two mixes were tested: untreated and glass enriched. The modified mix achieved higher compressive strength, better thermal insulation, and lower environmental impact, while rapid drying maintained structural integrity. The method offers a scalable, low-carbon solution aligned with circular economic principles.

Internal erosion of soil is the main factor behind embankment dam failure. Such failure has a devastating impact on properties and human lives. The susceptibility of internal erosion is represented by an erosion rate index (IHET) value. Evaluation of IHET experimentally is expensive, time-consuming, and affected by many physical and mechanical soil properties. In this research, Artificial Neural Network (ANN) model based on experimentally obtained values of liquid limit, plasticity index, initial water content, initial dry density, internal friction, and cohesion for sixteen types of clay soils have been developed to predict IHET. The IHET corresponding to these different parameters was obtained using the Hole Erosion test and compared with those obtained from the ANN model. The erosion rate index of these soils obtained from ANN models correlated with that obtained from experimental results. The performance indices such as the coefficient of determination (R2) and mean square error (MSE) were used to evaluate the performance of the prediction capacity of the models developed in this study. The developed models achieved R2 and MSE values of 0.9508 and 0.040216, respectively. Thus, it can be concluded that the ANN is an efficient tool to predict the erosion rate index of clay soil.

Seepage forces due to the flow of water inside embankment hydraulic structures, such as dams or levees, result in internal erosion or piping. This will result in a reduction in soil strength, causing the failure of hydraulic structures. Stabilization of the soil is one of the most effective approaches to avoid such catastrophic failure and prevent significant loss of life and property. The objective of this research is to stabilize sandy soil against internal erosion using fly ash (FA) alone and fly ash mixed with alkali-activated binder (NaOH). Although fly ash is commonly used for clay soil, its reactivity with alkali activators like NaOH makes it a potential candidate for stabilizing non-cohesive sandy soils when combined with alkaline solutions. A well-graded sandy soil was selected and mixed with fly ash alone and fly ash with sodium hydroxide at different percentages. Compaction curves were determined for each percentage, and specimens from the mix were remolded at 98% relative compaction and optimum moisture content corresponding to the compaction curve value. The hole erosion test (HET) was employed to evaluate internal erosion parameters. During the hole erosion test, seepage conditions were simulated by applying a controlled water flow through remolded specimens to replicate erosion caused by internal seepage forces. Additionally, the internal erosion parameters were evaluated at different curing times (2 days, 7 days, and 28 days were selected to capture short-term, intermediate, and long-term effects of chemical reactions on soil stabilization). Parameters such as the friction factor, coefficient of soil erosion, and critical shear stress were obtained, and the erosion rate index (I_HET) was determined. It was found that using FA–NaOH significantly reduced internal erosion and increased the erosion rate index and the critical shear of the soil. The addition of 10% fly ash mixed with activated-alkali binder at 7 days curing time stabilized the soil against erosion. At this percentage, the erosion rate index equal to 5.3 and soil was categorized as: “very slow erosion”. However, mixing the sand with fly ash alone has a small or insignificant effect on the internal erosion of the soil, especially at higher percentages of fly ash. The optimum percentage of fly ash alone to improve the soil resistance to internal erosion was found to be 5% at 28 days of curing time where the soil rated as “moderately slow”.

Clay soils are known to have a high swelling pressure with an increase in water content. This behavior is considered a serious hazard to structures built upon them. Various mechanical and chemical treatments have historically been used to stabilize the swelling behavior of clay soils. This work investigates the potential use of shredded plastic waste to reduce the swelling pressure and compressibility of clay soils. Two types of highly plastic clay (CH) soils were selected. Three different dimensions of plastic waste pieces were used, namely lengths of 0.5 cm, 1.0 cm, and 1.5 cm, with a width of 1 mm. A blend of plastic–cement waste with a ratio of 1:5 by weight was prepared. Different fractions of the plastic–cement waste blend with a 2 wt.% increment were added to the clay soil, which was then remolded in a consolidometer ring at 95% relative compaction and 3.0% below the optimum. The zero swell test, as per ASTM D4546, was conducted on the remolded soil samples after three curing periods: 1, 2, and 7 days. This method ensures the accurate evaluation of swell potential and stabilization efficiency over time. The experimental results showed that the addition of 6.0–8.0% of the blend significantly reduced the swelling pressure, demonstrating the mixture’s effectiveness in soil stabilization. It also reduced the swell potential of the expansive clay soil and had a substantial effect on the reduction in its compressibility, especially with a higher aspect ratio. The compression index decreased, while the maximum past pressure increased with a higher plastic–cement ratio. The 7-day curing time is the optimum time to stabilize expansive clay soils with the plastic–cement waste mixture. This study provides strong evidence that plastic waste can enhance soil mechanical properties, making it a viable geotechnical solution.

Geothermal energy piles or ground heat exchange (GHE) systems embrace a sustainable source of energy that utilizes the geothermal energy naturally found inside the ground in order to heat and/or cool buildings. GHE is a highly innovative system that consists of energy loops within foundation elements (shallow foundations or piles) through which a heat carrier fluid circulates, enabling heat extraction or storage in the ground. Despite the innovation and potential of GHE systems, there are significant challenges in harmonizing their thermal and mechanical designs due to the complex interactions involved. This review critically examines state-of-the-art design methodologies developed to address these complexities, providing insights into the most recent advancements in GHE performance and design. Key findings include innovative techniques such as advanced numerical modeling to predict thermomechanical behavior, the use of different pipe configurations to optimize heat transfer, and strategies to minimize thermal stress on the foundation. Additionally, this review identifies research gaps, including the need for more comprehensive full-scale experimental validations, the impact of soil properties on system performance, and the long-term effects of thermal cycling on pile integrity. These insights aim to contribute to a better understanding of the thermomechanical behavior of energy piles, ultimately facilitating more accurate and effective design solutions.