Effect of landfill leachate on the hydromechanical behavior of bentonite-geomaterials mixture

Demdoum, Abdellah; Gueddouda, Mohamed Kamel; Goual, Idriss; Souli, Hanène; Ghembaza, Moulay Smaîne

doi:10.1016/j.conbuildmat.2019.117356

Cited by 24 publications

(1 citation statement)

References 34 publications

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“…Akgun [ 42 ] evaluated the permeability properties of bentonite in southern Turkey and measured that the hydraulic conductivity of the bentonite–sand mixtures was 8.73 × 10 −10 m/s. Demdoum [ 43 ] conducted hydraulic conductivity tests on composites with 10% bentonite, 20% sand, and 70% tuff, and the result was 1.44 × 10 − 10 m/s. The addition of polymer significantly reduces the hydraulic conductivity of bentonite–sand mixtures.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

confidence: 99%