In recent years, there has been an increased focus on the research of earthen construction, driven by the rising demand for low-cost and sustainable building materials. Numerous studies have investigated the properties of compressed earth blocks (CEBs), however, very few have examined the properties of earth-based mortar. Mortar is an essential component and further investigation is required to enhance the mechanical performance of CEB structures. The study focuses on raw earth mortar (REM), which is a rudimentary mix of water with natural earth consisting of sand, silt and clay. Through experimental investigation, the fresh and hardened properties of three REM mixes were examined to determine the influence of cement stabilisation and jute fibre reinforcement. Shear triplet CEB assemblages were manufactured and tested to determine the initial shear strength of each mortar mix. The addition of 20 mm jute fibre at 0.25 % by weight increased the compressive and flexural strength of cement-stabilised raw earth mortar by 12 % and 20 % respectively. The addition of jute fibre also enhanced the initial shear strength, angle of internal friction and coefficient of friction during shear triplet testing. Finite element analysis (FEA) was undertaken to model the failure mechanism of the CEB assemblages, employing the use of cohesive zone modelling. The results of the FEA provided a satisfactory correspondence to the behaviour observed during experimental analysis and were within +/- 5.0 % of the expected values. The outcome of this investigation demonstrates the potential of REM and contributes to the development of low-cost and sustainable earth construction.

Stinging nettle (Urtica dioica L.) has been observed to grow spontaneously on metal-contaminated soils marginalised by heavy industrial use, thereby presenting an opportunity for the economic utilisation of such lands. This study explores the potential of nettle as a fibre crop by producing short fibre-reinforced polylactic acid (PLA) composites through compounding and injection moulding. Whole stem segments from three nettle clones (B13, L18, and Roville), along with separated fibre bundles from the L18 clone, were processed. The fibre bundles were separated using a roller breaker unit and a hammer mill. From separation with the hammer mill, not only cleaned fibre bundles but also the uncleaned fibre-shive mixture and the undersieve fraction were processed. The Young's modulus of all composites exceeded that of unreinforced PLA, with mean values ranging from 5.7 to 8.1 GPa. However, the tensile strength of most composites was lower than that of pure PLA, except for the two composites reinforced with cleaned fibre bundles. Of these two, the reinforcement with fibre bundles from separation with the hammer mill led to superior mechanical properties, with a higher Young's modulus (8.1 GPa) and tensile strength (61.8 MPa) compared to those separated using the breaking unit (7.2 GPa and 55.9 MPa). This enhancement is hypothesised to result from reduced fibre damage and lower fibre bundle thickness. The findings suggest that nettle cultivation on marginal lands could be a viable option for producing short-fibre composites, thereby offering a sustainable use of these otherwise underutilised areas.

Fibre reinforcement technology has been widely adopted in soil improvement due to its cost-effectiveness, simplicity, and environmental benefits. In many fibre reinforcement projects, the soil is often in an unsaturated state. However, the numerical simulation mechanisms of fibre-reinforced unsaturated soils remain poorly understood. In this study, a Vangenuchten (VG) model considering fibre incorporating fibres was proposed based on the original VG model. This model considering fibre accurately describes the soil water characteristic curve (SWCC) of fibre-reinforced sand (FRS), as verified by water-holding characteristics tests. Then, unsaturated triaxial tests confirmed the applicability of an unsaturated soil elastoplastic constitutive model and a fully coupled soil-water-air finite element-finite difference (FE-FD) method for simulating the mechanical behaviour of unsaturated FRS. Finally, using the SWCC parameters derived from the VG model considering fibres and mechanical parameters from saturated triaxial tests, slope models were established to analyse the stability of both unreinforced and fibre-reinforced slopes. The results show that the interweaving action of fibres within the soil enhances its strength, reduce permeability, and decreases both saturation and pore water pressure, ultimately increasing slope stability. This study provides valuable insights into the SWCC characteristics and the numerical calculation of FRS under unsaturated conditions.

A common physical technique assessed for improving expansive clays is by the addition of natural fibres to the soil. A good understanding of the impact of stabilisation using fibres on the clay soil's constituents, microfabric, and pore structure is, however, required. Mixtures of clay and fibre, regardless of type or extent, can never change the natural composition of the clay. Even the smallest part must still consist of spaces with clay with the original physical properties and mineralogy. This suggests that, although the mixture may show beneficial physical changes over the initial clay soil, its spatial attributes in terms of mineralogical characteristics, remain unchanged. This paper discusses some of the fundamentals that are not always adequately considered or addressed in expansive clay research, aiming to improve the focus of current and future research investigations. These include the process, mechanics, and implications of chemical and physical soil treatment as well as the concept of moisture equilibration.

This study investigates the mechanical, thermal, and wears characteristics of eco-friendly composite materials (designated as N1 to N5) with varying ratios of silicon nitride (biogenic Si3N4) and biochar along with jute and kenaf microfiber. The primary aim of this research study was to investigate the suitability of low cost biomass derived functional ceramic fillers in composite material instead of high cost industrial ceramics. Both the bio carbon and biogenic Si(3)N(4 )were synthesized from waste sorghum husk ash via pyrolysis and thermo-chemical method. Further the composites are prepared via mixed casting process and post cured at 100 degrees C for 5 h. According to results, the mechanical properties show a consistent improvement, attributed to the contributions of biogenic Si3N4. Moreover, the specific wear rate decreases progressively, with a larger biogenic Si(3)N(4 )and bio carbon filler %. The presence of biochar acts as solid lubricant and offered balanced friction coefficient. The composite N4 attained maximum mechanical properties including tensile (110 MPa), flexural (173 MPa), impact (6.1 J), hardness (82 shore-D), compressive (138 MPa) and lap shear strength (16 MPa). On contrary, the composite N5 attained least thermal conductivity of 0.235 W/mK, Sp. Wear rate of 0.00545 with COF of 0.26. Similarly, the scanning electron microscope (SEM) analysis revealed highly adhered nature of fillers with matrix, indicating their cohesive nature indicating the strong interfacial adhesion between the fillers and the matrix, attributed to the presence of biochar, which enhances mechanical interlocking and provides functional groups that promote chemical bonding with the polymer matrix, leading to improved load transfer efficiency and overall composite performance. Moreover, thermal conductivity values exhibit a marginal decline with the presence of biogenic Si(3)N(4)and biochar. Overall, the study demonstrated that biomass-derived functional fillers are capable candidates for providing the required toughness and abrasion-free surfaces, as evidenced by the increased impact strength, improved wear resistance, and enhanced durability observed in treated specimens compared to the control samples.This approach offers both economic and environmental benefits by reducing human exposure to hazardous pollutants through the utilization of biomass-derived materials, which help divert waste from landfills, lower air pollution caused by burning conventional plastics, and minimize soil contamination from non-biodegradable waste. In addition, the developed natural fiber-reinforced composites exhibited competitive mechanical performance compared to conventional industrial ceramic-reinforced composites, demonstrating comparable strength, enhanced toughness, and improved damping properties while offering the advantages of lower density, biodegradability, and cost-effectiveness. These findings highlight the potential of biomass-derived fillers as sustainable alternatives in structural applications.

This study introduces a novel method for stabilising expansive subgrade soils by integrating microbially induced calcite precipitation (MICP) process with a synergistic combination of waste sugarcane bagasse and recycled polyester fibres. This innovative approach aims to enhance strength properties and reduce volume susceptibility. The study demonstrates increases in Unconfined Compressive Strength (UCS), Split Tensile Strength (STS), and California Bearing Ratio (CBR), while substantially decreasing linear shrinkage, swell strains and pressures, indicating improved soil stability. The study also investigates the microstructural and chemical transformations through SEM-EDS, FTIR, and DSC-TGA, further corroborated by 16S metagenomic sequencing to understand microbial dynamics. Optimal stabilisation results were obtained with 0.5% fibre content and a four-day mellowing period, enhancing soil structure and durability by calcite precipitation and leveraging the combined benefits of natural and synthetic fibres. These fibres strengthen the soil structure and facilitate calcite nucleation, ensuring lasting stability, particularly valuable for stabilising expansive subgrade soils.

The production of agricultural residues causes environmental pollution, especially in regions with intensive horticultural production. The solution is to maximise the use of residues, applying the 'zero waste' model and using them to develop construction materials. Natural fibres used to reinforce materials have environmental and economic benefits due to their low cost. This research presents an innovative characterisation using an inverted-plate optical microscope, a high-resolution scanning electron microscope (HRSEM) and a 3D X-ray microscope. A physico-mechanical and chemical characterisation of horticultural fibres was also conducted. The fibres analysed were those produced in the highest quantities, including those from tomatoes, peppers, zucchinis, cucumbers and aubergines. The viability of these natural fibres for use as reinforcements in biocomposites was investigated. The analysis centred on studying the microstructure, porosity, chemical composition, tensile strength, water absorption and environmental degradation of the natural fibres. The results showed a porosity ranging from 47.44% to 61.18%, which contributes to the lightness of the materials. Cucumber stems have a higher tensile strength than the other stems, with an average value of 19.83 MPa. The SEM analysis showed a similar chemical composition of the scanned fibres. Finally, the life cycle of the materials made from horticultural residue was analysed, and negative GWP (global warming potential) CO2eq values were obtained for two of the proposed materials, such as stabilised soil reinforced with agricultural fibres and insulation panels made of agricultural fibres.

Corn silk (CS), an agricultural byproduct obtained after the processing of corn, is usually dumped as waste. Worldwide there is a growing concern to utilise this waste for making value-added products. This work tried to improve the functional properties of corn silk fibres and utilise them to fabricate biocomposites for automotive applications. Raw corn silk fibres were alkali treated (2%, 45 min) to achieve around 11% improvement in tensile strength, 14% improvement in elongation-at-break and 26% reduction in initial modulus. The alkali-treated fibres were further processed to prepare bi-directional carded webs which were ultimately reinforced in PLA matrix utilising compression-moulding technology. The biocomposites developed with different mass fractions (10% to 50%) of alkali-treated corn silk fibres were evaluated for their functional properties. The biocomposite, formulated with 40% mass fractions of treated corn silk fibre and poly(lactic) acid, exhibited the highest mechanical performance-tensile strength (74.57 MPa), Young's modulus (4.28 GPa), Flexural strength (442.45 MPa), breaking elongation (2.04%) and impact strength (3.2 kJ/m2). The biocomposites were also found to be thermally stable with no significant weight loss till 319 degrees C and 98.49% final weight loss at the end of 780 degrees C. Those biocomposites exhibited biodegradability with 2.73% weight loss and 13.11% strength loss in 30 days of burial in soil. The biocomposite reinforced with 40% alkali-treated corn silk fibres demonstrated high potential for automotive namely door panels, exterior under-floor panels, instrument panels, internal engine covers, packaging trays, seat backs, etc. Moreover, this study advances sustainable biocomposites by enhancing CS fibre properties, achieving superior mechanical strength, thermal stability, and biodegradability for automotive applications.

This work focused on the development of a hydrophobic biocomposite film reinforced with natural jute fiber. The biocomposite was made using a blend of chitosan and guar gum and reinforced with varying concentration of jute fiber followed by casting and air drying in petri dishes. Microscopic analysis of the cross-sectional structure of the films revealed a dense, compact morphology and FTIR result shows evidence of chemical interaction of the composite components. The inclusion of Jute fiber was found to increase the water repellant capacity of the films. The film water vapor permeability (WVP) was reduced from 4.1 x 10(-10) (g/m(2)center dot day center dot kPa) to 1.2 x 10(-10) (g/m(2)center dot day center dot kPa) with addition of jute fiber. Although the presence of Jute affects color properties of the films, it significantly improved their ability to block UV-Vis light. The tensile strength and elongation at break of CS/GG 0 % JT film, CS/GG/1 % JT, CS/GG/1.25 %JT and, CS/GG/1.5 % JT film was turned out to be (38.4 MPa, 45.3 MPa, 51.6 MPa and 60 MPa), (15.33 %, 17.66 %, 21.33 % and, 14 %) respectively. Notably, an increased in the DPPH radical scavenging assay was also observed from similar to 87 % in CS/GG composite to 99.4 % (1 % JT film), 99.66 % (1.25 %JT film) and 99.83 % for 1.5 % JT reinforced films respectively. Furthermore, all films showed excellent antimicrobial activity against the foodborne pathogen Escherichia coli and Fusarium oxysporum fungi highlighting their potential as active food packaging material. Signs of biodegradation were observed following four month of soil burial test, confirming the environmental sustainability of the produced biocomposite film.

The impact of the field conditions on needle-punched mulches made of cellulose fibres and PLA biopolymer during the 300 days of exposure was investigated. The study observed the degradation of nonwoven mulches during specific exposure periods (30, 90, 180 and 300 days), evaluating their mechanical, morphological and chemical properties. The impact of nonwoven mulches on soil temperature and moisture, consequently on the number of microorganisms developed beneath mulches after 300 days of exposure, were analysed and associated with obtained results complementing comprehension of nonwoven mulch degradation. The findings show that nonwoven mulches made from jute, hemp, viscose and PLA fibres change when exposed to environmental conditions (soil, sunlight, rainfall, snow, ice accumulation, air and soil temperatures, wind). The changes include alterations in colour, structure shifts and modifications in properties. The results highlight the degradation pathways of cellulose and PLA mulches, revealing that cellulose-based fibres degrade through the removal of amorphous components, leading to increased crystallinity and eventual structural breakdown. WAXD findings demonstrated that microbial and environmental factors initially enhance crystalline regions in cellulose fibres but ultimately reduce tensile strength and flexibility due to amorphous phase loss. FTIR analysis confirmed the molecular changes in cellulose chains, particularly in pectin and lignin, while SEM provided direct evidence of surface damage and fibre disintegration. Furthermore, it was found that fibre types of nonwoven mulch influence soil moisture retention and soil microbial activity due to a complex interplay of fibre composition, environmental conditions and nonwoven fabric characteristics. Comprehensive mechanical, morphological and chemical results of different types of nonwoven mulch during the 300 days of exposure to the field conditions provide valuable insights into sustainable practices for using nonwoven mulches for growing crops.