Swelling behavior of kaolinitic clays contaminated with alkali solutions: A micro-level study

Chavali, Rama Vara Prasad; Vindula, Sai Kumar; Reddy, P. Hari Prasad; Babu, Ambili; Pillai, Rakesh J.

doi:10.1016/j.clay.2016.10.045

Cited by 43 publications

(11 citation statements)

References 31 publications

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“…Indeed, exposing Opalinus clay to a hyper alkaline solution triggers several mechanism among which the acid-base reactions concentrated at clay particles edges. An increase in the negatively charged groups occurs resulting in higher repulsive forces (Chavali et al 2017;Walther. 1996), thus higher porosity (higher void ratio) leading to an increase in the measured swelling pressure.…”

Section: Resultsmentioning

confidence: 99%

Impact of alkalinity on the swelling behavior of Opalinus Clay

et al. 2020

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Section: Resultsmentioning

confidence: 99%

Impact of alkalinity on the swelling behavior of Opalinus Clay

et al. 2020

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“…Both minerals belong to the group of feldspathoids, which present anhydrous tectosilicates highly resembling feldspars with a somewhat different structure and lower silicate content [40]. Swelling of the soil sample stabilized with 6% MKG could be thus attributed to dispersion of clay particles and new mineral formations (i.e., sodalite and cancrite) as reported by Chavali et al [41] for kaolinite-rich soils. Namely, having prismatic to spherical crystal morphologies, occasionally even partially hydrated [42], these newly formed crystallites might have substantially added to the overall soil volume.…”

Section: Mineralogy Of Natural and Treated Soilsmentioning

confidence: 91%

“…Strong peak intensity of cancrinite in the soil treated with 12% MKG is explained by kaolinite recrystallization in a Na-rich environment. Chavali et al [41] and Zhao et al [45] reported on the transformation of kaolinite to sodalite and cancrinite as a result of the addition of NaOH. Similar results were observed by Lapides and Heller [46] who noticed that the so-called X and A zeolites present the main crystalline products formed from the reaction of metakaolin and colloidal silica with NaOH.…”

Section: Mineralogy Of Natural and Treated Soilsmentioning

confidence: 99%

The Role of Clay Swelling and Mineral Neoformation in the Stabilization of High Plasticity Soils Treated with the Fly Ash- and Metakaolin-Based Geopolymers

et al. 2018

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In the southern U.S. states, expansive soils are frequently encountered, presenting an important hazard in geotechnical engineering. This research relies on mineralogical and geochemical clues to explain the swelling behavior of smectite-rich, high-plasticity soils, documented in a series of geomechanical swelling tests that were performed on the soils stabilized with the metakaolin (MKG) and fly ash (FAG) based geopolymers. These geopolymers were mixed with the soil at several concentration levels. The lowest swelling percentage was shown to correspond to the sample stabilized with 12% FAG and was attributed to the neoformation of calcium silicate hydrates that acted as a cementitious material, preventing the soil from expanding by occupying the pore space, thus binding the clay particles together. Conversely, the 12% MKG-stabilized soil exhibited enormous expansion, which was explained by montmorillonite swelling to the point that it gradually began to lose its structural periodicity. The relatively high abundance of the newly formed feldspathoids in MKG-treated samples is believed to have greatly contributed to the overall soil expansion. Finally, the cation exchange capacity tests showed that the percentage of Na + and Ca 2+ , as well as the pH value, exercised strong control on the swelling behavior of smectitic soils.

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“…Several studies in the literature reporting the effects of exposure of geotechnical materials to chemically aggressive solutions (Agbenyeku et al, 2016;Chavali et al, 2017Chavali et al, , 2018Hamdi & Srasra, 2013;Li et al, 2013;Liu et al, 2015;Miguel et al, 2017;Sucha et al, 2002;Verástegui-Flores & Di Emidio, 2014), indicate, in general, that contact with acidic waters causes soil pH reduction, metal dissolution, chemical species desorption (Agbenyeku et al, 2016;Miguel et al, 2017), and cation exchange reactions with partial mineral dissolution (Chavali et al, 2018), in addition to changes in hydraulic conductivity in clayey soils (Hamdi & Srasra, 2013;Li et al, 2013;Liu et al, 2015) and modifications in their mechanical properties (Hassanlourad et al, 2016). However, Chavali et al (2018) highlight that most of these studies evaluate soil contamination by inorganic acidic solutions with pH under natural conditions (3 < pH < 6).…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Modifications in Geomaterials and Their Leachates Extracted from Acidic Attack

Ferrazzo¹,

Tímbola²,

Bragagnolo³

et al. 2020

S&R

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Exposure of geomaterials to acid leachates may cause chemical species desorption, mineral dissolution, and metal leaching. This study seeks to understand the changes in the physicochemical composition of liquid extracts resulting from the exposure of four different geomaterials (uniform fine sand, basalt residual soil, kaolin, and bentonite) to a blank solution (distilled water) and sulfuric acid solutions at the concentrations of 0.01, and 1.00 mol/L. It was also investigated the relationship between alterations in both chemical and mineralogical constitutions of geomaterials. The elemental composition of the geomaterials was determined by X-ray fluorescence. In the liquid extracts, Na, Mg, Al, K, Ca, Fe, and Mn concentrations were obtained by inductively coupled plasma atomic emission spectrometry, as well as pH and electrical conductivity were evaluated. pH and electrical conductivity data showed that bentonite had buffering capacity until 0.01 mol/L concentration and higher ion dissolution with increasing acid concentration. Acidic attack by the 1.00 mol/L solution resulted in the solubilization of the constituent metals, corresponding to reductions in elemental composition and alterations in geomaterials mineralogy.

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Swelling behavior of kaolinitic clays contaminated with alkali solutions: A micro-level study

Cited by 43 publications

References 31 publications

Impact of alkalinity on the swelling behavior of Opalinus Clay

Impact of alkalinity on the swelling behavior of Opalinus Clay

The Role of Clay Swelling and Mineral Neoformation in the Stabilization of High Plasticity Soils Treated with the Fly Ash- and Metakaolin-Based Geopolymers

Physicochemical Modifications in Geomaterials and Their Leachates Extracted from Acidic Attack

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