Rammed earth (RE) construction has gained increasing interest in recent years owing to sustainability demands in the construction industry and the advancement of digital fabrication techniques. However, the domination of the cement-stabilized RE material in the RE industry poses environmental concerns due to the substantial carbon emissions associated with cement production. In this study, bio-based alternatives to cement-stabilized RE are investigated through evaluating xanthan gum (XG) and animal glue (AG) as bio-binders for RE stabilization. Unconfined compressive strength tests are conducted on XG and AG-stabilized specimens for mechanical performance evaluation, and unstabilized RE samples as baseline for comparison. Results show that AG-stabilized specimens demonstrate a 294% strength improvement over unstabilized RE, reaching 6.86 MPa at 28 days, while XG-stabilized specimens achieve a 221% improvement. XG-stabilized specimens, however, exhibit susceptibility to microbial proliferation. The findings from this research demonstrate that XG and AG have the potential to be viable alternatives to mainstream RE construction methods, paving the way for advancing environmentally friendly RE construction.

The growing demand for environmentally sustainable and biodegradable materials has intensified interest in alternative solutions for thermal insulation. This study explores the development of composite materials using mango seed shell biochar (MSSB) and soy protein isolate (SPI) as a biodegradable matrix-filler system. Mango seed shells, an abundant agro-industrial waste, were subjected to pyrolysis at 500 degrees C for 2 hours to produce biochar. The resulting MSSB was incorporated into SPI with glycerol as a plasticizer to fabricate composite sheets containing 10%, 20%, and 30% biochar by weight Thermal conductivity tests showed that increasing MSSB content led to a notable reduction in thermal conductivity, with the 30% MSSB composite achieving a value of 0.035 W/mK-comparable to commercial synthetic foams such as expanded polystyrene. Mechanical analysis revealed a tradeoff between tensile and compressive properties. While tensile strength decreased from 1.8 MPa for pure SPI to 0.7 MPa at 30% MSSB, compressive strength improved with increasing biochar content, peaking at 1.5 MPa.Biodegradability was evaluated through an 8-week soil burial test, which demonstrated accelerated degradation in composites with higher MSSB content, reaching up to 55% weight loss at 30% loading. These findings highlight the potential of MSSB-SPI composites as eco-friendly insulation materials suitable for green building and packaging applications. Future work will focus on mechanical property enhancement to expand the material's structural utility.

For almost a decade, various studies have been carried out to prove the suitability of nano additives in enhancing the geotechnical properties of soil. Yet, this line of research is still in its elementary stage, restricting itself to laboratory tests to determine soil's index and engineering properties blended with varying dosages of nano additives. In other words, research on practical applications of nano additives for soil stabilization is scarce. The present work attempts to investigate the suitability of three different nanomaterials as a load-bearing stratum for shallow foundations. The nano additives were chosen in such a way that each of them is from a different origin. One of them is nano calcium carbonate (inorganic) whereas the other two are nano-sized varieties of natural biopolymers, namely nano chitosan (crustacean-based) and nano carboxymethyl cellulose (plant-based). A series of laboratory tests were initially conducted to determine the strength of all three nano-additive-treated soils at different dosages, which were investigated for 180 days to ensure their long-term performance. This was followed by a foundation model study on untreated soil and on soil treated with optimal dosages of nano additives. The results were validated using finite element software followed by a parametric study to optimize the depth of soil stabilization. It was observed that all three nano additives exhibited a better performance when the top layer had the optimal dosage and the subsequent layers had a relatively lesser dosage.

Recently, natural and environmentally friendly materials have been highly considered for soil reinforcement and stabilization in road and geo-environment infrastructures and constructions. In the present research, laboratory experiments are conducted to evaluate the potential of combining barley fibers and nanoclay to enhance the mechanical properties of clay subgrade while maintaining its affordability and environmental sustainability. Also, it is aimed to explore the potential for extensive use of barley fiber waste, which ranks as the second most abundant agricultural product globally. The laboratory samples were produced by including nanoclay at concentrations of 0.5%, 1%, and 1.5% and barley fibers at concentrations of 0.3%, 0.6%, and 0.9% with fiber lengths of 5 mm, 10 mm, and 15 mm. The primary objective was to determine the optimal content of nanoclay and the most effective fiber length through the unconfined compressive strength (UCS) test. Afterward, the nanoclay was used at its optimal concentration along with different ratios of fibers to perform California bearing ratio (CBR), direct shear, indirect tensile strength, and freeze/thaw (F/T) tests. In addition, scanning electron microscopy (SEM) imaging was employed to examine the mechanism of soil reinforcement by incorporating fibers and the enhancement achieved by the nanoclay introduction into the prepared samples. The results revealed that adding nanoclay to clay caused the development of a cohesive gel between particles and fibers, resulting in improved interlocking and friction. The results also demonstrated a significant increase in the UCS by 142%, tensile strength by 178%, CBR by 120%, and shear strength characteristics. Furthermore, the samples containing an appropriate amount of nanoclay exhibited enhanced durability and greater strength when subjected to F/T cycles. This research determined the optimal fiber length and dose as 10 mm and 0.6%, respectively. Additionally, the highest UCS was achieved with a nanoclay concentration of 1%. Overall, the test results illustrate the effectiveness of these stabilizers in improving the mechanical properties of clay subgrades.

Agricultural waste presents a significant environmental challenge due to improper disposal and management practices, contributing to soil degradation, biodiversity loss, and pollution of water and air resources. To address these issues, there is a growing emphasis on the valorization of agricultural waste. Cellulose, a major component of agricultural waste, offers promising opportunities for resource utilization due to its unique properties, including biodegradability, biocompatibility, and renewability. Thus, this review explored various types of agricultural waste, their chemical composition, and pretreatment methods for cellulose extraction. It also highlights the significance of rice straw, sugarcane bagasse, and other agricultural residues as cellulose-rich resources. Among the various membrane fabrication techniques, phase inversion is highly effective for creating porous membranes with controlled thickness and uniformity, while electrospinning produces nanofibrous membranes with high surface area and exceptional mechanical properties. The review further explores the separation of pollutants including using cellulose membranes, demonstrating their potential in environmental remediation. Hence, by valorizing agricultural residues into functional materials, this approach addresses the challenge of agricultural waste management and contributes to the development of innovative solutions for pollution control and water treatment.

In recent years, the potential of earth materials in construction has emerged as a sustainable pathway, offering environmental benefits compared to traditional methods. When used in raw form, earth materials can be recycled at the end of a building life, reducing construction waste. In parallel, integrating additive manufacturing into the architecture, engineering, and construction (AEC) sector has brought about a shift in construction dynamics, combining efficiency with precision. This paper bridges the study of 3D printing with earth-based fresh mortars, emphasising the capabilities of the Forced Layer Drying (FLD) technique in the additive manufacturing process to increase the mechanical performance of the printing mortar. This paper begins by defining the requisite rheological properties for successful 3D printing. A chosen material for this paper is Speswhite kaolin. An instrumental aspect of our research is exploring an established model for the drying rate of saturated porous media, such as earth and concrete, and its application to predict the evaporation rate of saturated earth-based mortar in 3D printing with forced drying conditions. The Wind Tunnel experiment was conducted to validate this model, examining the interplay of airflow speed and temperature on the evaporation rate. Further deepening this study, the soil water content and undrained shear strength are correlated, specifically based on models derived from oedometer geotechnical standard tests. This facilitated a comprehensive understanding of porous earth-based materials in various moisture scenarios. Our findings confirm that airflow, temperature, and the geometry of the printed object play instrumental roles in affecting evaporation rate, consequent mechanical performance, and structural build-up of the material. The paper wraps up by offering insights into the practical application of 3D printing using earth-based mortars, with a special focus on FLD technique.

This research aims to analyze the biodegradation dynamics of a tertiary composite blend, including High-Density Polyethylene (HDPE), starch and linen fiber, and their combined effect on decay processes in authentic environmental settings. It investigates the relationship between fiber content and decomposition rates, details the biodegradation mechanisms, and evaluates the reactive profiles of the involved constituents. Decay kinetics and the biodegradation mechanism of three formulations: HDPE60S40, HDPE60S20F20, and HDPE60S30F10, representing composites with 60 % HDPE, complemented by 40 %, 20 % starch and 20 %, 10 % linen fiber, respectively, are examined. HDPE60S30F10 is noted for its superior biodegradation rates, showing a 1.2 % weight loss in soil and 9.89 % in marine conditions and an increased resistance to shearing forces, whereas HDPE60S40 recorded a weight loss of 0,63 % in soil and 2.59 % in seawater against 1,7 % and 6.64 % in soil and seawtaer, respectively recorded with HDPE60S20F20. Density Functional Theory (DFT) and Molecular Dynamics (MD) simulations complement these findings, presenting HDPE60S40 as the most rigid, HDPE60S20F20 as the most ductile with a bulk modulus of 13.34 GPa, and HDPE60S30F10 exhibiting the best shear resistance with a shear modulus of 12.48 GPa. Scanning Electron Microscopy (SEM) and Fourier-Transform Infrared Spectroscopy (FTIR) analyses confirm microbial involvement and significant surface erosion, particularly indicating particularly starch degradation. The results suggest that integrating linen fiber into the composites enhances biodegradation.