Influence of biopolymer on gas permeability in compacted clay at different densities and water contents

Ng, Charles Wang Wai; So, Pui San; Lau, Sze Yu; Zhou, Chao; Coo, Jason Lim; Ni, Jun Jun

doi:10.1016/j.enggeo.2020.105631

Cited by 28 publications

(14 citation statements)

References 51 publications

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“…The XG initially lled in or near the pores either developed into bonding surface, merged into bridge links, or accumulated into ber matrices, which connected the adjacent soil frameworks closely 23,25,26,29,42 . As the contact area among the soil particles increased, the integrity of soil particles was enhanced, and the particle size of soil skeleton particles became larger.…”

Section: Resultsmentioning

confidence: 99%

“…The contents of XG were controlled at 0%, 0.5%, 1% and 2% by mass ratio (m b /m s ). The specimens were prepared by dry mixing technique 42 , which was to mix quantitative XG and loess powder evenly and then add quantitative water according to water content. After that, the XG-loess mixtures were placed in a sealed desiccator for braising for 24h.…”

Section: Microscopic Testmentioning

confidence: 99%

“…The microstructure is one of the means to explain mechanical behavior. During drying, the XG enhanced the strength of the soil by coating the surface of the soil particles, improved the permeability by lling the pores, and improved erosion resistance by increasing uid viscosity [41][42][43][44] . In addition, the ability of soil to resist external deformation under stress was enhanced by the cation bridging and hydrogen bonds between the carboxylic acid (-COOH) and hydroxyl (-OH) groups of XG and cations on the surface of particles 45 .…”

Section: Introductionmentioning

confidence: 99%

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Splitting tensile strength and microstructure of xanthan gum-treated loess

Zhang

Jiang

Zhao

2022

Preprint

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The tensile strength of loess is closely related to geological disasters. As an eco-friendly material, biopolymers have an excellent strengthening effect on the mechanical properties of soil. The effect of different initial dry densities and Xanthan gum (XG) contents on the microstructure and mechanical behavior of XG-treated loess was studied through a series of microscopic tests and splitting tensile tests based on the PIV technique. The results show that during the dehydration process, the XG became concentrated and agglomerated, forming bridge links between soil particles and covering the surface of soil particles. The XG-treated loess had a major concentration of micropores and mesopores, with greater peak intensities of pore size distribution curve than untreated loess. The load-displacement relation curves of specimens with different XG contents and initial dry densities showed strain-softening. The displacement vector field indicated that the primary cracks of specimens were radial vertical, the secondary cracks were well developed. With the increase of the XG content and initial dry density, the strain-softening phenomenon was more significant, the splitting tensile strength and brittleness of specimens were greater. XG treatment made the soils obtain stronger cementation and denser structure, which helped to increase strength and brittleness.

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Section: Resultsmentioning

confidence: 99%

Section: Microscopic Testmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Splitting tensile strength and microstructure of xanthan gum-treated loess

Zhang

Jiang

Zhao

2022

Preprint

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“…However, it is noteworthy to mention that the structural and chemical composition of biopolymers is rather complex. Their production costs at the commercial scale are very high compared to chemically synthesized polymers exhibiting similar characteristics [79]. Therefore, the Fig.…”

Section: Biopolymersmentioning

confidence: 99%

Removal and recovery of nutrients and value-added products from wastewater: technological options and practical perspective

Srivastava

Pothu

Sanchez

et al. 2021

Syst Microbiol and Biomanuf

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Wastewaters from various process industries, namely food and agricultural, sugar mill, brewery, milk, vegetable and fruit, and meat and fisheries processing industries and their wastewater effluents contain nutrients, organic matter, inorganic, heavy metals, suspended solids, and pathogens. The discharges of non-treated wastewater enter the nearby aquatic ecosystem (e.g., lakes, rivers) and are a significant concern due to the presence of different nutrients, competing ions and C containing pollutants. It causes excessive growth of algae, loss of habitat/species, and other negative impacts on human health/environment. In the present review, different treatment approaches have been discussed in utilizing these nutrients to synthesize value-added products such as biopolymer, biofuel, pigment, organic acid, or enzymes. These biopolymers can be used to prepare various food products/packaging materials. Dextran, chitosan, carrageenan, alginate, and pectin are good examples of non-food biopolymers. Besides these products, poly-β-hydroxybutyrate (PHB) synthesis from wastewater nutrients is reported as a new source of bio-nanocomposite materials/biopolymer-based coatings. In this review, the different treatment approaches are discussed, which are being used worldwide for the removal/recovery of nutrients, toxic pollutants, and the potential resource recovery of value-added products from wastewater.

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“…For those natural soils that have insufficient mechanical strength, soil treatment is often employed [1][2][3][4][5][6][7]. Recently, the incorporation of biopolymers into soil stabilisation has gained increasing credence in sustainable geotechnical engineering for their environmental benefits [8][9][10][11], high strengthening efficiency [12][13][14], abundance in nature [15][16][17], suitable functional properties such as pH stability and ionic salt compatibility [18][19][20] and reasonable prices [8,21,22]. Selected polysaccharide biopolymers (e.g., xanthan gum, agar gum, gellan gum, chitosan, beta-glucan, starch, guar gum and carrageenan) have proved their potential in improving the soil performances under external loads in terms of unconfined compression, triaxial compression, direct shear, interface shear, tension, three-point bending and split [20,[23][24][25][26][27][28][29][30][31][32][33][34].…”

Section: Introductionmentioning

confidence: 99%

The Optimisation Analysis of Sand-Clay Mixtures Stabilised with Xanthan Gum Biopolymers

Hao

Chen

et al. 2021

Sustainability

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Sand–clay mixtures can be encountered in both natural soils (e.g., residual soils, clay deposits and clinosols) and artificial fills. The method of utilising biopolymers in ground improvement for sand–clay mixtures has emerged recently. However, a full understanding of the strengthening effect of biopolymer-treated sand–clay mixtures has not yet been achieved due to a limited number of relevant studies. In this study, xanthan gum (XG), as one of the eco-friendly biopolymers, was used to treat reconstituted sand–clay mixtures that had various compositions in related to clay (or sand) content and clay type (kaolin and bentonite). A series of laboratory unconfined compression strength (UCS) tests were conducted to probe the performances of XG-treated sand–clay mixtures from two aspects, i.e., optimum treatment conditions (e.g., XG content and initial moisture content) to achieve the maximum strengthening effect and strengthening efficiency for the sand–clay mixtures with different compositions. The experimental results indicated that the optimum initial moisture content decreased as the sand content increased. The optimum XG content, which also decreased with the increasing sand content, remained approximately 3.75% for all sand–kaolin mixtures and 5.75% for all sand–bentonite mixtures if calculated based on clay fraction. While untreated sand–kaolin mixtures and sand–bentonite mixtures had comparable UCS values, XG-treated sand–kaolin mixtures seemed to have better improved mechanical strength due to higher ionic (or hydrogen) bonds with XG and low-swelling properties compared with bentonite. The deformation modulus of XG-treated sand–clay mixtures were positively related with UCS. The variation in UCS and stiffness for each treatment condition increased as the sand content was elevated for both sand-kaolin and sand-bentonite mixtures. An increment in the proportion of the heterogeneous composite formed by irregular sand particles conglomerated with the XG–clay matrix in total soil might be responsible for this phenomenon.

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Influence of biopolymer on gas permeability in compacted clay at different densities and water contents

Cited by 28 publications

References 51 publications

Splitting tensile strength and microstructure of xanthan gum-treated loess

Splitting tensile strength and microstructure of xanthan gum-treated loess

Removal and recovery of nutrients and value-added products from wastewater: technological options and practical perspective

The Optimisation Analysis of Sand-Clay Mixtures Stabilised with Xanthan Gum Biopolymers

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