The morphology of sheep wool applied as organic fertilizer biodegraded in the soil was examined. The investigations were conducted in natural conditions for unwashed waste wool, which was rejected during sorting and then chopped into short segments and wool pellets. Different types of wool were mixed with soil and buried in experimental plots. The wool samples were periodically taken and analyzed for one year using Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS). During examinations, the changes in the fibers' morphology were observed. It was stated that cut wool and pellet are mechanically damaged, which significantly accelerates wool biodegradation and quickly destroys the whole fiber structure. On the contrary, for undamaged fibers biodegradation occurs slowly, layer by layer, in a predictable sequence. This finding has practical implications for the use of wool as an organic fertilizer, suggesting that the method of preparation can influence its biodegradation rate. (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(SEM)(sic)(sic)(sic)(sic)(sic)X(sic)(sic)(sic)(sic)(EDS)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic). (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic), (sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic)(sic).

This study explores a novel stabilization technique combining Persian gum (PG), an eco-friendly biopolymer, and glass fiber (GF) to enhance the strength and durability of fine-grained soils under freeze-thaw (F-T) cycles. Specimens were prepared at maximum dry density (MDD) with varying PG and GF contents, cured for 0, 7, or 14 days, and subjected to 0, 5, 7, or 10 F-T cycles. Tests included Standard Proctor compaction, Scanning Electron Microscopy (SEM), Unconfined Compressive Strength (UCS), and Direct Shear (DS). Results demonstrated that GF significantly improved durability, ductility, and strength by enhancing interparticle interaction and friction angle. The results indicated that at an optimum GF content of 1%, UCS and E-5(0) increased by up to 35%. Also, after 10 F-T cycles, UCS decreased by 46% for untreated soil and 36% for treated soil. PG enhanced cohesion through interparticle bonding, which was curing-time-dependent. Specimens with 2.5% PG (optimum content) showed a 133% UCS increase after 14 days of curing but a 9% reduction after 5 F-T cycles, with 70% of total UCS loss occurring in the first 5 cycles. The tests indicated that formation of large and stable soil-PG-GF matrix with improved rigidity, strength, and F-T resistance. The results demonstrated that the suggested soil stabilization method, which utilizes low-cost, eco-friendly materials, was effective.

The use of various sustainable materials and cement is a frequent and successful strategy for stabilizing problematic soil. The current research discusses the potential use of discarded millet husk ash (MHA) and cement (C) as subgrade ingredients to improve the geotechnical qualities of soil (S). MHA and cement are mixed in different proportions and the engineering characteristics of the stabilized soil are studied. The study involves examining fundamental properties, such as specific gravity and Atterberg's limits, as well as engineering properties, including Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests. These evaluations are conducted to assess the feasibility of using the MHA-cement blend as a construction material. Additionally, FTIR & SEM analysis shows the addition of MHA-cement blend effectively couples with the soil. The test findings demonstrate that adding MHA to soil lead to decreased liquid limits and plasticity indices. The maximum dry density (MDD) was observed to decrease when MHA was mixed with soil. When 8% cement was incorporated to the S:MHA (84.5:7.5) combination, the UCS value rose even higher reaching 1600.1 kPa. The S:MHA:C arrangement in the ratio of 84.5:7.5:8 had the greatest California bearing ratio (CBR). Fourier transform infrared spectroscopy (FTIR) elucidated the various types of bond formations present within the soil composite and deeper peaks depicted greater presence of cementitious compounds after curing period. SEM analysis exhibited a greater density of N-A-S-H and C-A-S-H gels in comparison to natural soil samples. The findings suggest that the MHA-cement blend can effectively enhance the geotechnical properties of problematic soils, while addressing issues of agricultural waste management. This research contributes to several Sustainable Development Goals (SDGs), including SDG 9 (Industry, Innovation, and Infrastructure) by promoting innovative construction materials.

Coastal regions often face challenges with the degradation of cementitious foundations that have endured prolonged exposure to corrosive ions and cyclic loading induced by environmental factors, such as typhoons, vehicular traffic vibrations, and the impact of waves. To address these issues, this study focused on incorporating Nano-magnesium oxide (Nano-MgO) into cemented soils to investigate its potential impact on the strength, durability, corrosion resistance, and corresponding microstructural evolution of cemented soils. Initially, unconfined compressive strength tests (UCS) were conducted on Nano-MgO-modified cemented soils subjected to different curing periods in freshwater and seawater environments. The findings revealed that the addition of 3% Nano-MgO effectively increased the compressive strength and corrosion resistance of the cemented soils. Subsequent dynamic cyclic loading tests demonstrated that Nano-modified cemented soils exhibited reduced energy loss (smaller hysteresis loop curve area) under cyclic loading, along with a significant improvement in the damping ratio and dynamic elastic modulus. Furthermore, employing an array of microscopic analyses, including nuclear magnetic resonance (NMR), X-ray diffraction (XRD), and scanning electron microscopy (SEM), revealed that the hydration byproducts of Nano-MgO, specifically Mg(OH)2 and magnesium silicate hydrates, demonstrated effective pore space occupation and enhanced interparticle bonding. This augmentation markedly heightened the corrosion resistance and durability of the cemented soil.

The impact of four distinct calcium sources on the microbial solidification of sand in the Kashi Desert, Xinjiang, was investigated. A wind tunnel test over a 60-day period revealed the cracking behavior of four different complex calcium nutrient solutions. By comparing the bearing capacity and the results from dry-wet cycling and freeze-thaw cycle tests, it was concluded that the sample treated with calcium gluconate exhibited superior sand fixation performance, whereas the sample treated with calcium acetate showed weaker sand fixation effects. The microstructure of the treated sand samples was analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD). Elemental analysis was conducted via energy dispersive spectroscopy (EDS), and functional groups were identified through Fourier transform infrared spectroscopy (FTIR). These experimental findings hold significant implications for soil remediation, pollutant removal in soil, enhancement of soil fertility, and desert soil stabilization.

This work studied biocomposites based on a blend of low-density polyethylene (LDPE) and the ethylene-vinyl acetate copolymer (EVA), filled with 30 wt.% of cellulosic components (microcrystalline cellulose or wood flour). The LDPE/EVA ratio varied from 0 to 100%. It was shown that the addition of EVA to LDPE increased the elasticity of biocomposites. The elongation at break for filled biocomposites increased from 9% to 317% for microcrystalline cellulose and from 9% to 120% for wood flour (with an increase in the EVA content in the matrix from 0 to 50%). The biodegradability of biocomposites was assessed both in laboratory conditions and in open landfill conditions. The EVA content in the matrix also affects the rate of the biodegradation of biocomposites, with an increase in the proportion of the copolymer in the polymer matrix corresponding to increased rates of biodegradation. Biodegradation was confirmed gravimetrically by weight loss, an X-ray diffraction analysis, and the change in color of the samples after exposition in soil media. The prepared biocomposites have a high potential for implementation due to the optimal combination of consumer properties.

Soil improvement via cement-based stabilizers is often necessary to improve the workability and strength of problematic soils. However, understanding the underlying mechanisms of the stabilization process merits further study, particularly concerning changes in the microscale structure that affect macroscale behavior. Mercury intrusion porosimetry (MIP) and scanning electron microscopy (SEM) are often paired to characterize the microstructure and pore networks and can be used to quantitatively describe pore structure and surface complexity. Fractal geometry (e.g., fractal dimension and lacunarity) has been shown to provide a quantitative description of structural complexity in nature. Therefore, these fractal geometry fundamentals (fractal dimension and lacunarity) were implemented in the analysis of SEM micrographs and MIP results of a single-mineral kaolinitic soil (SA-1 kaolinite) stabilized with a portland cement stabilizer (portland cement Type I/II) to better understand the evolution of the soil microstructure with curing time. Particle size distributions (PSD) were developed based on image analysis of SEM micrographs collected at curing times of 1, 7, 14, 28, and 90 days. The surface fractal dimension obtained via analysis of MIP results was used to describe changes occurring in the pore network with curing time. The formation of cementitious products was inferred from changes in the PSD as gels first formed and then fused with clay surfaces. Box-counting fractal dimensions and lacunarity showed evidence of particle restructuring with cementation. The transition pore size between intraaggregate and interaggregate pores, obtained via fractal analysis of MIP data, decreased with curing time, indicating the formation of hydration products with stabilization. Using fractal geometry to help analyze the microstructural properties of stabilized clays may lead to better insight into their engineering scale behavior. Problematic soils pose an expensive problem to engineers and are often treated with cement-based stabilizers to improve strength and decrease compressibility or the potential to deform or collapse. However, the underlying mechanism causing problematic behavior, such as low strength or shrinking and swelling, is not well understood and techniques to characterize these soils at the microscopic level are needed to better prevent the damage posed to infrastructure. The current standard of practice utilizes only qualitative measurements of the soil structure and cannot be used in models attempting to predict clay behavior. Therefore, concepts from fractal geometry were used in this study to provide a quantitative, measured value of the soil and pore surface which can be used in future models. Analysis of images at the microscale provided a quantitative measurement of the change in soil structure as stabilization reactions occurred. Moreover, the geometric parameters obtained showed strong correlations with strength values, indicating the utility of the technique for predicting engineering behavior. The results of this study show promise for adapting the box-counting procedure to other, more complex soils. Additionally, because there was a good correlation between the fractal parameters and strength, the results should be correlated with other soil parameters.