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This study investigated the rheological and compression-permeability attributes of dredged slurry reinforced using waste rice straws. Recognizing the potential of natural waste fibers in geotechnical applications, this study aimed to elucidate the effects of fiber length and pretreatment processes on the relocation dynamics of the cemented slurry. A series of laboratory evaluations were conducted to gauge critical parameters such as flow consistency, viscosity, one-dimensional compression, and hydraulic conductivity. Results indicated that straw lengths greater than 0.075 mm significantly increased slurry slump flow due to altered surface area and water adsorption. Dynamic viscosity decreased with increasing straw length, yet overall performance improved with straw inclusion. The influence of immersing straws in pure water emerged as a determinant in the study. A 24-h pretreatment duration influenced the flowability, viscosity, and the structural integrity of the fibers. Based on the observations, the study deduces that straw powder finer than 0.075 mm, subjected to a 24-h immersion in pure water, optimally bolsters the flow properties of cemented waste slurry. While the benefits associated with elongated straw fibers necessitate exploration and validation, this work underscores the potential of rice straw as a sustainable reinforcement material in geotechnical endeavors, promoting waste recycling and reducing environmental impact.

期刊论文 2025-05-04 DOI: 10.1080/1064119X.2024.2366516 ISSN: 1064-119X

In this paper, an extensive series of direct shear box tests (99 tests) were conducted to explore and compare the effects of raw and treated natural fibers, specifically Doum fibers on the mechanical behavior of three categories of sandy soils with distinct mean particle sizes (D50 = 0.63, 1, and 2 mm). Specimens from every soil category, containing 0 to 0.8% raw Doum fibers and 0 to 1% treated Doum fibers in incremental step of 0.2%, were reconstituted at an initial relative density of (Dr = 87 +/- 3%) and subjected to three different initial normal stresses (100, 200, and 400 kPa). The obtained results indicate that incorporating raw or treated Doum fibers improve the mechanical and rheological properties (internal friction angle, ductility, and maximum dilatancy angle) of the tested mixtures up to specific thresholds Doum fiber content (FD = 0.6% and FTD = 0.8% for raw and treated Doum fibers respectively). Beyond these limiting values, the mechanical and rheological properties decreased with further increases in Doum fiber content. Additionally, specimens reinforced with treated Doum fibers exhibit higher shear strength than that of the raw Doum fibers for all tested parameters. Based on the experimental results, it has been found to suggest a reliable correlation between Particle Size Distribution (PSD) characteristics and mechanical properties for all reconstituted specimens. The recorded soil trend is especially pronounced for the mean grain size (D50) ranging between 1 and 2 mm, where a notable increase in shear resistance is noticed. The analysis of the obtained outcome suggests the introduction of new enhancement factors (EF tau peak and EF phi degrees) as useful parameters for predicting the mechanical behavior of sand-fibers mixtures. Furthermore, new relationships have been developed to forecast changes in mechanical properties (peak shear strength, internal friction angle, and maximum dilatancy angle) of the tested mixtures under the impact of the selected parameters (FD/TD, D50, and sigma n).

期刊论文 2025-04-01 DOI: 10.1007/s40999-024-01062-0 ISSN: 1735-0522

This study investigated the mechanical properties of rammed earth (RE) stabilized with cement or lime and reinforced with straw. Specifically, the compressive and tensile strengths of 15 different mix designs were analyzed, including unstabilized RE, RE stabilized with lime or cement (at 4 % and 8 % by weight of soil), and RE reinforced with straw (at 0.5 % and 1.0 % by weight of soil), along with various combinations of stabilized and unstabilized RE reinforced with straw. Mechanical properties were further assessed through ultrasonic testing and scanning electron microscopy (SEM). Additionally, a data-driven fuzzy logic model was developed to estimate the mechanical properties of RE, addressing a key gap in the application of fuzzy logic to RE construction. The results showed that stabilizing RE with cement and lime increased its 28-day dry compressive strength by 365% to 640% and 109% to 237%, respectively. The addition of straw generally reduced compressive strength. The stress-strain curves indicated that the elastic modulus of RE stabilized with cement and lime increased by up to 350% and 11 %, respectively. The 28-day dry tensile strength of the samples ranged from 0.17 to 0.56 MPa. Furthermore, the addition of stabilizers improved tensile strength by approximately 88 % to 224 %, while straw enhanced the tensile strength of unstabilized RE by about 35 %. Ultrasonic and SEM analyses provided valuable insights into the mechanical properties of RE. Additionally, the fuzzy logic model proved useful, yielding satisfactory results in predicting the properties of RE, particularly when using the centroid defuzzification method. The study concluded that RE materials when properly cured and effectively stabilized with cement, lime, and straw, can achieve acceptable mechanical properties and offer sustainable benefits.

期刊论文 2025-03-01 DOI: 10.1016/j.clema.2025.100300

Expanding on the challenges of expansive soils to civil infrastructure, this research delves into the synergistic application of microbially induced calcium carbonate precipitation (MICP) through bio-stimulation and natural fiber reinforcement to mitigate soil swell-shrink behavior and enhance soil strength. This research diverges from traditional methods by addressing their economic and environmental limitations. The dual strategy of bio-stimulation with natural fiber reinforcement was assessed through laboratory tests, including unconfined compression, 1D swell, linear shrinkage tests, and microstructural analysis. This methodology involved preparing solutions to foster bacterial growth and strategically adding jute fibers to enhance the soil matrix. Results revealed significant improvements in soil strength (up to 186%), and reductions in swell strain (up to 85%) and swell pressure (up to 90%), with the optimal jute fiber content at 1.5%. Additionally, a significant increase in calcium carbonate content (163-176%) highlighted bio-stimulation's role in soil stabilization. SEM analysis showed that bio-stimulation and jute fiber reinforcement transformed the soil microstructure, enhancing cohesion and reducing deformability. These outcomes highlight the promise of combining bio-stimulated MICP with natural fiber reinforcement as an eco-friendly and efficient approach to soil stabilization. They also add to the growing body of knowledge on tackling the issues posed by expansive soils in civil engineering applications.

期刊论文 2025-03-01 DOI: 10.1007/s10064-025-04159-5 ISSN: 1435-9529

This study evaluates the utilization of rice straw as a reinforcement material in dredged slurry, focusing on sustainable waste-to-waste treatment practices. Unconfined compressive strength (UCS) tests were conducted on slurries with varying straw contents and sizes, including samples pretreated via pure water immersion. The study also analyzed the desiccation behavior of straw-reinforced slurry, examining parameters such as crack initiation time, maximum crack width, surface crack ratio, and failure morphology. Results indicate that straw fiber degradation within the first 72 h of aqueous pretreatment impacts the mechanical properties and structural integrity of the reinforced slurry. The introduction of straw alters the slurry's failure mode from brittle to plastic, enhancing ductility and residual strength. Optimal reinforcement occurred with a 0.5 % straw content, pretreated for 24 h, showing significant improvements in UCS and stiffness. Additionally, straw content between 3 % and 5 % optimally reduces cracking, with straw sizes of 0.6-1.0 mm providing effective crack control without disrupting the soil matrix. These findings suggest that straw can significantly enhance both the strength and dewatering efficiency of dredged slurry, offering practical implications for geotechnical applications in construction and landfill settings.

期刊论文 2025-02-14 DOI: 10.1016/j.conbuildmat.2025.140005 ISSN: 0950-0618

Using recycled waste for soil improvement is a sustainable strategy that can reduce resource consumption. In this paper, recycled polyester fiber (RPF) is proposed to improve the engineering performance of red mud- improved volcanic ash (RV). A series of mechanical test were performed for RVs with five different content of RPF. And the microstructure was also investigated using scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and mercury intrusion porosimetry (MIP) tests. Results show that RPF significantly reinforces the mechanical strength and toughness of RV and the optimum content of RPF is 0.9%. The Unconfined compressive strength (UCS), cohesion (c) and internal friction angle (phi) of reinforced soil enhanced by up to 122%, 40% and 8% compared to untreated soil at the optimum incorporation and optimum water content, respectively. The failure model of RPF-reinforced RV is converted from brittle to ductile, and the toughness parameters are significantly improved. Microscopic investigations reveal that RPF forms a complex three-dimensional structure within the reinforced soil. Adhesion and friction interactions at the fiber-matrix interface are the main reasons for the enhancement of strength and toughness. However, the performance of composites does not continue increasing with RPF content. Excessive fibers gather and twist to form weak zones, reducing the strength and stiffness of material. In practice, the optimal fiber content needs to be controlled to ensure the best mechanical properties. This eco-friendly soil improvement can promote the harmless utilization of red mud and waste polyester materials contributing to ground improvement techniques in volcanic areas.

期刊论文 2024-11-01 DOI: 10.1007/s10064-024-03962-w ISSN: 1435-9529

Soil stabilization using polymers and fibers has been widely investigated in recent years. This study introduces an innovative approach by integrating synthetic polymer (AH polymer) with natural fibers (sisal fiber) for sand stabilization. A comprehensive experimental framework was established to assess the impact of varying polymer content (1%, 2%, 3%, and 4%) and fiber content (0.2%, 0.4%, 0.6%, and 0.8%, by the mass of dry sand), and densities, on the mechanical properties of stabilized sand, including compressive strength (UCS), tensile strength (TS), and flexural strength (FS). The synergistic stabilization effects of the polymer and fibers were elucidated through SEM. The findings indicate that the synergistic application of AH polymer and sisal fibers significantly enhances the structural integrity of sand. Notably, the UCS, TS, and FS exhibited a well-linear relationship with both the polymer and fiber content. The strengthening effect of fiber was particularly pronounced in samples with higher polymer content. According to the strength increase rate, the optimal polymer content is 2%, and optimal fiber content is 0.6% for the UCS, 0.4% for the TS and 0.8% for the FS. An increase in density was observed to linearly augment the UCS and FS. For sand with 2% polymer and 0.8% fiber, the TS increased linearly with the increment in density, however, for sand with 4% polymer and 0.4% fiber, TS kept a non-monotonic relationship with density. The study also revealed that augmenting the content of polymer and fibers diminishes the brittleness of the stabilized sand, whereas an increase in density has the opposite effect. Furthermore, the incorporation of polymer and fibers resulted in an elevated deformation modulus. The polymer functions as an adhesive, binding fibers to sand particles, while the fibers create a network-like structure that amplifies the effective contact area among sand particles, thereby substantially improving the mechanical properties of the sand.

期刊论文 2024-06-01 DOI: 10.1007/s10064-024-03716-8 ISSN: 1435-9529

This study investigates the potential of integrating areca fiber as a reinforcement agent in Compressed Stabilized Earth Blocks (CSEBs), used in combination with cement. Traditional earth-based construction methods, once prevalent, have seen a decline in industrialized nations with the advent of modern building materials. However, there is a growing resurgence in the use of earth-based materials, motivated by their economic, social, and environmental sustainability benefits. This renewed interest in CSEBs is primarily due to their superior energy efficiency and lower greenhouse gas emissions, especially when compared to conventional materials like fired clay bricks or concrete blocks. Areca catechu, widely recognized as the areca palm, thrives in the tropical regions of the Pacific, Asia, and East Africa. The fibers derived from areca nutshells, often regarded as agricultural waste, present an intriguing material for study. While the application of areca fiber in soil reinforcement has been previously acknowledged in scholarly literature, its specific role in enhancing the engineering properties of CSEBs represents a novel area of exploration, which this research aims to address comprehensively. In this research endeavor, CSEBs were manufactured with varying proportions of areca fibers, spanning from 0 % to 3 %, based on the dry mass of soil. Subsequently, these blocks underwent comprehensive testing to assess their strength and durability characteristics. Strength properties were evaluated through unconfined compression, split tensile strength, and flexural strength tests, while durability was meticulously examined using wet strength, water absorption, submersion, and efflorescence tests. Here, CSEBs displayed increases in compressive strength (107.04-436.38 %), split tensile strength (208.66-358.08 %), and flexural strength (16.49-82.47 %). Durability tests revealed enhanced wet compressive strength (up to 100.42 % increase) and optimized water absorption rates. A notable finding is identifying 2 % areca fiber content as optimal, yielding significant improvements in strength and durability parameters. Microstructural analysis using Scanning Electron Microscopy (SEM) further confirmed the benefits of 2 % fiber content, showing a compact and cohesive internal structure with reduced voids and fissures. This microstructural integrity underlines the enhanced bonding and stability imparted by the areca fibers. Another essential aspect of the study was evaluating the compliance of CSEBs with various international standards on earthen construction. The fiber-reinforced blocks met or exceeded several standards, demonstrating their suitability for broader construction applications. Finally, this study underscores the promise of areca fiber as a valuable reinforcement material in CSEBs stabilized with cement. This innovative approach offers a sustainable and eco-friendly building material option, aligning with the growing emphasis on environmentally conscious construction practices.

期刊论文 2024-05-10 DOI: 10.1016/j.conbuildmat.2024.136290 ISSN: 0950-0618

This paper investigates the effects of incorporating dispersed fibrous reinforcement in hydraulically bound granular 0/16-mm mixtures. The evaluated fibrous reinforcement comprised a mixture of polypropylene and alkali-resistant glass fibers in a 1:2 weight ratio. The fibrous reinforcement was added to the mixtures in amounts of 0.05% and 0.10% by weight. The prepared mixtures utilized 1% of CEM II/B-V 32.5 R Portland cement together with 3.5%, 7%, and 14% of fly ash, characterized by a high content of reactive calcium oxide. It was found that the fibrous additives had only a small effect on the maximum dry densities and virtually none on the optimum moisture contents of the mixtures. The use of the fiber mix significantly improved the compressive strength of the reinforced samples resulting after 42 days of curing, with a performance comparable to a reference mixture bound with 8% of Portland cement. The addition of fibrous reinforcement increased the indirect tensile strength of the mixtures by up to 300%, resulting in a performance similar to that of a reference mixture with 5% of Portland cement. It was found that the use of this particular fibrous reinforcement significantly improved the performance of predominantly fly-ash-bound granular mixtures, allowing the reduction in cement content used in this type of material.

期刊论文 2024-03-01 DOI: 10.3390/app14062618
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