Hydraulic performance of anionic polymer-treated bentonite-granular soil mixtures

Güler, Erol; Ozhan, Hakki O.; Karaoglu, Selcuk

doi:10.1016/j.clay.2018.02.047

Cited by 22 publications

(7 citation statements)

References 16 publications

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“…Then, the mixtures were mixed with the oven-dried sand in order to obtain the bentonite-sand mixtures with a bentonite content of 15% by mass. The bentonite content was chosen as 15% because this amount maintained the optimum permeability for a bentonite-sand mixture [16].…”

Section: Testing Methodsmentioning

confidence: 99%

Measuring shear strength parameters of polymer-added bentonite-sand mixtures in laboratory experiments

Ozhan

2019

E3S Web Conf.

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In order to evaluate the shear strength parameters of an anionic polymer-added bentonite-sand mixture that was permeated with tap water, Proctor compaction tests and direct shear tests were performed on the mixture with a bentonite content of 15% by mass. The polymer content in the polymer-bentonite mixture was chosen as 0.5, 1, 2, 5, 10, 15 and 20% by mass, respectively. According to the results, maximum dry unit weight (Vdmax) first decreased as the polymer content was increased to 1% and then, increased. Vdmax of 20% polymer-added mixture and the mixture without polymer addition was measured as 17.55 and 17.28 kN/m3, respectively. Test results indicated that cohesion (c) increased and internal friction angle (ø) decreased due to polymer addition. 2% polymer addition caused an increase of 42 kPa in c but a decrease of 4.2° in ø. As the polymer content increased, maximum shear strength of the mixture (τmax) increased. τmax increased from 171.8 to 197.8 kPa as the polymer content was increased from 0 to 2%. As a result, 2% anionic polymer-added bentonite-sand mixture provided sufficient increase in the shear strength of the mixture.

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Section: Testing Methodsmentioning

confidence: 99%

Measuring shear strength parameters of polymer-added bentonite-sand mixtures in laboratory experiments

Ozhan

2019

E3S Web Conf.

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“…In recent years, the design engineers have preferred to use geosynthetic clay liners (GCLs) as an alternative to the CCLs as the barrier material in the waste disposal facilities [ 76 ]. Moreover, the GCLs have some advantages over the CCLs such as having lower hydraulic conductivity (<10 −10 m/s), lower thickness (4–10 mm), lower cost, less labor work and faster installation [ 72 , 77 , 78 ]. The most critical component of a GCL that determines the hydraulic performance of the barrier material is the bentonite layer [ 79 , 80 , 81 ].…”

Section: Solid Waste Disposal Facilities and Their Potential Role As A Source For Microplasticsmentioning

confidence: 99%

Microplastic Contamination in Soils: A Review from Geotechnical Engineering View

Monkul

Ozhan

2021

Polymers

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Microplastic contamination is a growing threat to marine and freshwater ecosystems, agricultural production, groundwater, plant growth and even human and animal health. Disintegration of plastic products due to mainly biochemical or physical activities leads to the formation and existence of microplastics in significant amounts, not only in marine and freshwater environments but also in soils. There are several valuable studies on microplastics in soils, which have typically focused on environmental, chemical, agricultural and health aspects. However, there is also a need for the geotechnical engineering perspective on microplastic contamination in soils. In this review paper, first, degradation, existence and persistence of microplastics in soils are assessed by considering various studies. Then, the potential role of solid waste disposal facilities as a source for microplastics is discussed by considering their geotechnical design and addressing the risk for the migration of microplastics from landfills to soils and other environments. Even though landfills are considered as one of the main geotechnical structures that contribute to the formation of considerably high amounts of microplastics and their contamination in soils, some other geotechnical engineering applications (i.e., soil improvement with tirechips, forming engineering fills with dredged sediments, soil improvement with synthetic polymer-based fibers, polystyrene based lightweight fill applications), as potential local source for microplastics, are also mentioned. Finally, the importance of geotechnical engineering as a mitigation tool for microplastics is emphasized and several important research topics involving geotechnical engineering are suggested.

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“…It is frequently utilized in environment-related materials due to its excellent swelling properties and low permeability [ 8 , 9 , 10 ]. To protect soil and groundwater from pollution, landfills often use compacted clay liners (CCL), geosynthetic clay liners (GCL), geomembranes, and bentonite–sand mixtures (BS) as barrier systems [ 11 , 12 ]. However, CCL often cracks because of uneven settlement or dryness, which significantly weakens its impermeability.…”

Section: Introductionmentioning

confidence: 99%

Study on Preparation of Polymer-Modified Bentonite and Sand Mixtures Based on Osmotic Pressure Principle

Zhang

et al. 2022

Materials

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Polymer-modified bentonite and sand mixtures (PMBS) are widely used in the engineering field due to their low cost and low permeability. In this study, different ionic types of polyacrylamides were used to modify bentonite to improve its swelling properties and impermeability. The physicochemical properties of polymer-modified bentonite were characterized by X-ray diffraction, particle size distribution, IR spectroscopy, SEM, and free swell index (FSI) to further demonstrate the successful organic modification of bentonite. To investigate the impermeability mechanism of PMBS from the perspective of osmotic pressure, the colloidal osmotic pressure of bentonite and hydraulic conductivity were compared. The results showed that anionic polyacrylamide (APAM) had the most obvious improvement on the swelling properties of bentonite, and 3% APAM increased the FSI of bentonite from 15 mL/2 g to 41 mL/2 g. With the increase in polymer dosage, the colloidal osmotic pressure of bentonite increased and the hydraulic conductivity of PMBS decreased significantly. The interior of PMBS is equivalent to a highly concentrated bentonite–sand–water system. When the colloidal osmotic pressure in the restricted space is higher than the external hydraulic pressure, it will prevent infiltration from occurring. When the external hydraulic pressure exceeds the high concentration of bentonite colloid osmotic pressure, the hydraulic conductivity may increase rapidly. Therefore, the impermeability of PMBS depends on the colloidal osmotic pressure of bentonite. Finally, it was confirmed that PMBS had a self-healing capacity by simulating damage to PMBS.

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Hydraulic performance of anionic polymer-treated bentonite-granular soil mixtures

Cited by 22 publications

References 16 publications

Measuring shear strength parameters of polymer-added bentonite-sand mixtures in laboratory experiments

Measuring shear strength parameters of polymer-added bentonite-sand mixtures in laboratory experiments

Microplastic Contamination in Soils: A Review from Geotechnical Engineering View

Study on Preparation of Polymer-Modified Bentonite and Sand Mixtures Based on Osmotic Pressure Principle

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