Influence of nano-SiO2 on geotechnical properties of fine soils subjected to freeze-thaw cycles

Kalhor, Amir; Ghazavi, Mahmoud; Roustaei, Mahya; Mirhosseini, Seyed Mohammad

doi:10.1016/j.coldregions.2019.03.011

Cited by 75 publications

(19 citation statements)

References 30 publications

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“…That is, addition of water and cement or nanocement to the soil environment organizes chemical bonds by mixing hydrogen, lime ,and silica over time, which raises soil resistance (Yousefi et al, [30]). This mechanism confirmed in many previous stuides (Majdi et al [33]; Kalhor et al [24];…”

Section: Before Applying Freeze-thaw Cyclessupporting

confidence: 88%

“…The prepared samples were put in a digital refrigerator to apply F-T cycles. The cylindrical pieces were placed at -20 °C for 12 hours and at +20 °C for 12 hours (Qi et al, [12]; Roustaie et al, [20]; Kalhor et al, [24]), and each F-T cycle lasted 24 hours. Figure 5 depicts the respective phases for preparing soil-stabilizer mixtures, cylindrical representatives, and a group of specimens placed in the F-T cycle device.…”

Section: Freeze-thaw Cyclesmentioning

confidence: 99%

“…Also, soils stabilized with silica foam particles showed a more brittle behavior than natural soils.Luo et al [23] suggested that the critical dynamic stress of clayey soil exposed to F-T cycles increased by adding lime and cement. Kalhor et al [24] examined the effectof nano-SiO 2 on the resistance behavior of clayey soil during F-T cycles. Based on their results, natural soil strength decreased by 64% after applying nine F-T processes, while clayey soil strength decreased by 52, 42, and 49% under the same number of F-T processes when treating the soil specimens with 1, 2,and 3% nano-SiO 2 , respectively.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effect of freeze-thaw cycles on mechanical properties of fine grain soil modified by cement and nanocement

2021

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Freeze-thaw (F-T) cycles cause substantial detriment to geotechnical structures, especially roads, every year. Recently, researchers have increasingly used nanomaterials to improve soil resilience. This study evaluated the effect of soil stabilization by nanocement and cement on resistance changes subjected to F-T cycles. For this purpose, clayey soil was combined with 1, 2, 3, and 4% stabilizers based on dry unit weight. Atterberg limits and standard compaction tests were performed on the prepared mixtures. The results showed that increasing the stabilizers enhanced the optimal moisture content, liqid limit, as well plastic limit while decreasing the maximum dry density and plastic limit. Then, the cylindrical specimens of the pure and stabilized soilswere prepared and cured within 42 days. Finally, unconfined compressive strength (UCS) tests were performed on the specimens after applying zero, three, six, and nine F-T cycles. UCS in the stabilized soil increased to a value about 12 times that in the pure soil. The UCS value was reduced on average to 49% in the pure soil specimens by applying nine F-T cycles, which further decreased on average to 36% and 31% after adding cement and nanocement, respectively.

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Section: Before Applying Freeze-thaw Cyclessupporting

confidence: 88%

Section: Freeze-thaw Cyclesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The effect of freeze-thaw cycles on mechanical properties of fine grain soil modified by cement and nanocement

2021

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“…As a result, the functionalization prevents the nanoparticle’ aggregation in liquids and improves their chemical stability [ 16 ]. Various applications of magnetite-alkoxysilane nanoparticles are known, such as detoxifying agents in ecological control [ 17 ], for drug delivery systems in medicine [ 18 ], technical use as thermal insulators [ 19 ], for soil stabilization [ 20 , 21 , 22 ], and in significant soil improvement [ 23 ]. It has been reported that SiO 2 -based nanoparticles could be used as fertilizers to enhance a seed germination and stimulate antioxidant system of crops [ 24 ]; they could also be used for pesticide delivery [ 25 ] and increasing the SiO 2 entering into the terrestrial system [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Effects of Modified Magnetite Nanoparticles on Bacterial Cells and Enzyme Reactions

et al. 2020

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Current paper presents biological effects of magnetite nanoparticles (MNPs). “Relations of MNP’ characteristics (zeta-potential and hydrodynamic diameters) with effects on bacteria and their enzymatic reactions were the main focus.”. Photobacterium phosphoreum and bacterial enzymatic reactions were chosen as bioassays. Three types of MNPs were under study: bare Fe3O4, Fe3O4 modified with 3-aminopropyltriethoxysilane (Fe3O4/APTES), and humic acids (Fe3O4/HA). Effects of the MNPs were studied at a low concentration range (< 2 mg/L) and attributed to availability and oxidative activity of Fe3+, high negative surface charge, and low hydrodynamic diameter of Fe3O4/HA, as well as higher Fe3+ content in suspensions of Fe3O4/HA. Low-concentration suspensions of bare Fe3O4 provided inhibitory effects in both bacterial and enzymatic bioassays, whereas the MNPs with modified surface (Fe3O4/APTES and Fe3O4/HA) did not affect the enzymatic activity. Under oxidative stress (i.e., in the solutions of model oxidizer, 1,4-benzoquinone), MNPs did not reveal antioxidant activity, moreover, Fe3O4/HA demonstrated additional inhibitory activity. The study contributes to the deeper understanding of a role of humic substances and silica in biogeochemical cycling of iron. Bioluminescence assays, cellular and enzymatic, can serve as convenient tools to evaluate bioavailability of Fe3+ in natural dispersions of iron-containing nanoparticles, e.g., magnetite, ferrihydrite, etc.

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“…For silt that has undergone freeze-thaw cycles, the improvement effect of nanomaterials is also effective, which is specifically reflected in improving the optimal moisture content, liquid limit, and plastic limit of soil and reducing the maximum dry density and plasticity index [44]. Compared with the untreated soil, the unconfined compressive strength of the soil added with 2% nano-SiO 2 decreases less [45]. In addition to the excellent improvement properties of nano-metal oxides and nano-inorganic compounds, the incorporation of nanomaterials can enhance each material in the composite materials.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Microscopic Properties of Graphite/Laterite Nanocomposites

Gao

Zhang³

et al. 2021

Advances in Materials Science and Engineering

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The effectiveness and improvement mechanism of graphite nanoparticles (GN) in strength properties and microstructure characteristics of regional laterite were analysed in this study. Dry density was also taken into consideration, and the effects of graphite nanoparticle (GN) content and dry density were mainly addressed. Triaxial tests, consolidation tests, and penetration tests were used to analyse the effectiveness of different dry densities and graphite nanoparticle mass ratios on the properties of laterite; microscopic methods such as scanning electron microscopy (SEM) tests were used to analyse the improvement mechanism. The results show that the increase in dry density can make the laterite more compact. The large specific surface area and nanoeffects of the graphite nanoparticles (GN) induce the attraction between soil particles after mixing, both of which make the laterite’s shear strength; compression index and impermeability have been enhanced to varying degrees. The microscopic tests showed that, as the content of graphite nanoparticles (GN) continues to increase, when it exceeds 1.0%, the attraction between soil particles increases and coarse particles are formed, which leads to the increase of the pores of the soil. In addition, the graphite nanoparticles have a certain degree of lubricity, a high amount of graphite nanoparticles enters the laterite soil layer, increasing the distance and gap between the layers, making it easy to separate the coarse particles from the coarse particles, and the strength increase is reduced. However, it is still stronger than that of the plain laterite.

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Influence of nano-SiO2 on geotechnical properties of fine soils subjected to freeze-thaw cycles

Cited by 75 publications

References 30 publications

The effect of freeze-thaw cycles on mechanical properties of fine grain soil modified by cement and nanocement

The effect of freeze-thaw cycles on mechanical properties of fine grain soil modified by cement and nanocement

Effects of Modified Magnetite Nanoparticles on Bacterial Cells and Enzyme Reactions

Mechanical and Microscopic Properties of Graphite/Laterite Nanocomposites

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