Permeability and compressibility of wax-coated sands

Bardet, Jean Pierre; Jesmani, Mehrab; Jabbari, Nima; Lourenço, Sérgio D. N.

doi:10.1680/geot.14.d.002

Cited by 5 publications

(3 citation statements)

References 16 publications

(24 reference statements)

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“…Although natural water-repellent soils are commonly found throughout the world [ 14 ], they may be unsuitable engineering materials because of highly anisotropic and heterogeneous water-repellent characteristics and the likelihood that natural water repellants will not persist for long. Therefore, artificially created water-repellent soils by using wax [ 17 ], organosilanes [ 18 , 19 ], and other hydrophobic agents [ 11 , 20 ] have recently been investigated because they exhibit homogeneous water repellency and it is easy to control the degree of water repellency. Because artificial water-repellent sandy soils can be used as alternative construction materials for several purposes, such as surfaces for horse racing tracks [ 17 ], waterproofing layer of highways [ 13 ], water harvesting [ 21 ], and landfill barrier systems [ 22 , 23 , 24 ], many studies have been performed to characterize the engineering properties of artificial water-repellent sands.…”

Section: Introductionmentioning

confidence: 99%

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

et al. 2016

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Water-repellent soils have a potential as alternative construction materials that will improve conventional geotechnical structures. In this study, the potential of chemically treated water-repellent kaolin clay as a landfill cover material is explored by examining its characteristics including hydraulic and mechanical properties. In order to provide water repellency to the kaolin clay, the surface of clay particle is modified with organosilanes in concentrations (CO) ranging from 0.5% to 10% by weight. As the CO increases, the specific gravity of treated clay tends to decrease, whereas the total organic carbon content of the treated clay tends to increase. The soil-water contact angle increases with an increase in CO until CO = 2.5%, and then maintains an almost constant value (≈134.0°). Resistance to water infiltration is improved by organosilane treatment under low hydrostatic pressure. However, water infiltration resistance under high hydrostatic pressure is reduced or exacerbated to the level of untreated clay. The maximum compacted dry weight density decreases with increasing CO. As the CO increases, the small strain shear modulus increases, whereas the effect of organosilane treatment on the constrained modulus is minimal. The results indicate that water-repellent kaolin clay possesses excellent engineering characteristics for a landfill cover material.

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Section: Introductionmentioning

confidence: 99%

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

et al. 2016

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“…Chemical methods to render sands hydrophobic include the use of agents such as fatty acids (Subedi et al 2012), waxes (Bardet et al 2014), oils (Zhang et al 2016) and organosilanes (Ng and Lourenço, 2016). From a sample preparation perspective, mixing organosilanes in liquid form with sands, being a single step process is the most straightforward and also a welldocumented method that has been shown to induce hydrophobicity in sands while also retaining their non-biodegradability in water (Bachmann and McHale, 2009).…”

Section: = 2 Cosmentioning

confidence: 99%

Optimising the hydrophobicity of sands by silanisation and powder coating

2019

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Sands are naturally hydrophilic granular materials, yet, rendering them hydrophobic could lend them to a wide range of geotechnical applications. This study describes a powder coating procedure performed after chemically modifying the surfaces of coarse, medium and fine sands and examines its effect on their hydrophobicity. The purpose is to render these granular materials more hydrophobic than what is conventionally achieved by chemical methods using a simple technique. The procedure consists of first silanising both the sands and silica powder at a similar concentration by means of an organosilane to modify their surface chemistry, then the silica powder is adhered to the sands at a mass mixing ratio to alter their hydrophobicity.Irrespective of the concentrations and mixing ratios, the powder coating procedure enhances the hydrophobicity of sands in comparison to the sole use of the chemical method. Changes in the morphology of the sand grains, such as their particle size, particle shape and surface roughness resulting from the powder coating procedure are examined by means of dynamic image analysis, profilometry and scanning electron microscopy. The effects of surface chemistry, surface roughness and air on the hydrophobicity of the sands are discussed based on theoretical wetting models to analyse the experimental results.

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“…Recently, the use of "superhydrophobic sand" has been proposed, to realize the storage and transportation of the surface water of sandy soils [7][8][9][10][11][12]. Various methods, such as the combustion of oil waste [13], crude oil emulsion [14], paraffin wax [15], natural wax [16], and oil and fatty acids [17] have been proposed for the development of hydrophobic coatings. The hydrophobic petroleum waxes were divided into three principle groups-paraffin waxes, microcrystalline waxes, and petrolatum.…”

Section: Introductionmentioning

confidence: 99%

Coating Sand with New Hydrophobic and Superhydrophobic Silica/Paraffin Wax Nanocapsules for Desert Water Storage and Transportation

et al. 2019

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Paraffin wax emulsions have gained immense attention as a cheap, environment-friendly, and aroma-free material for preparing superhydrophobic coatings. In this work, paraffin wax (PWs) capsules consisting of hydrophobic silica nanoparticles were used for coating desert sand. Different types of the hydrophobic silica nanoparticles, modified with new oleylamino- and oleylamide silane precursors, were prepared in the presence and absence of paraffin waxes. The particle sizes, surface charges, thermal stability, surface morphologies, and wetting characteristics of these nanoparticles were investigated. The combination of these superhydrophobic silica nanoparticles and desert sand, showed excellent water repellency; stable water droplets remained on the sand surface, without any wetting or permeation. Furthermore, the mixing of the superhydrophobic sand with untreated sand (mixing ratio 1:10 wt %), with a thickness of 2 cm, sustained a great water-holding capacity with a water column height of 35 cm. The good thermal stability of the PWs capsules containing hydrophobic silica nanoparticles, along with their good water-holding capacity, make them potential candidates for developing superhydrophobic sand for desert water storage and transportation.

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Permeability and compressibility of wax-coated sands

Cited by 5 publications

References 16 publications

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

Engineering Characteristics of Chemically Treated Water-Repellent Kaolin

Optimising the hydrophobicity of sands by silanisation and powder coating

Coating Sand with New Hydrophobic and Superhydrophobic Silica/Paraffin Wax Nanocapsules for Desert Water Storage and Transportation

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