Stabilization of swelling clays by Mg(OH)2. Factors affecting hydroxy-Mg-interlayering in swelling clays

Xeidakis, G. S.

doi:10.1016/s0013-7952(96)00046-4

Cited by 24 publications

(6 citation statements)

References 21 publications

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“…Addition of Mg(OH) 2 causes smoothening of the CVM peak and disappearance of small peaks. The disappearance of these peaks indicates alteration in the structure of the clay though it is not destroyed completely [28]. The mineralogy changes fairly depict an analogous behaviour to the response of treated soil for index and engineering properties.…”

Section: X-ray Diffraction Studiesmentioning

confidence: 75%

“…However, their adsorption mechanism is different, with lime being more active on the external surface compared to Mg(OH) 2 which gets intercalated both externally and internally. In the case of lime, the mechanism of stabilisation continues further with chemical bonding and crystallisation through the long-term pozzolanic reactions [28]. However, this aspect requires further research in the case of Mg(OH) 2 -treated soil.…”

Section: Swelling Characteristicsmentioning

confidence: 99%

“…Further the addition of CaCl 2 eliminates the problem of mixing and pulverizing due to its greater solubility compared to other alkaline additives [26,27]. Alternatively compounds like Mg(OH) 2 also gives a comparable behaviour as that of lime except that lime does not get internally adsorbed [28]. Addition of Mg(OH) 2 causes an internal adsorption of Mg 2+ ions leading to the formation of a interlayer brucite sheet which curtails swelling; incidentally the Mg 2+ has the ability to develop faster reactions compared to Ca 2+ .…”

Section: Introductionmentioning

confidence: 99%

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Effect of Functional Group of the Inorganic Additives on Index and Microstructural Properties of Expansive Soil

Bhuvaneshwari

Robinson

Gandhi

2020

Int. J. of Geosynth. and Ground Eng.

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Expansive soils exhibit volume-change behaviour on exposure to moisture changes due to the presence of the montmorillonite mineral. The swell-shrink behaviour of these soils could lead to instability of the structures found on them, specifically the lightweight structures and pavements. Chemical stabilisation of expansive soils has always proven to be more successful in mitigation of swelling, compared to other methods of removal, replacement, and structural alterations. The present study focuses on the behaviour of a representative expansive soil treated with a conventional inorganic additive (lime) and less explored additives like calcium chloride and magnesium hydroxide, with a view to understand the effect of functional group of the inorganic additives in curtailing the swelling behaviour of the soil. The phenomenon of stabilisation is compared in terms of index and engineering properties based on the quantity of additives and curing period adopted. The macrostructural properties are evaluated through the changes in the plasticity characteristics, stress-strain behaviour, swell and permeability properties. The microstructural aspects of the treated soils are determined in terms of specific surface area, pore size measurements and minerology. Microlevel and macrostructural parameters are correlated to understand the soil-additive interaction and to quantify the extent of stabilisation and permanence of the additive induced changes. The lime and Mg(OH) 2-treated samples effectively alleviate plasticity characteristics of the soil. However, strength of the limeamended soil gets significantly improved, contributing to nearly 180% increase in strength compared to 100% and 45% increase for CaCl 2-and Mg(OH) 2-amended soils. Further, the additives also completely nullify the swelling phenomenon. The microstructure properties, SSA and pore size of the treated soils are concomitant with the macrolevel properties, such as permeability, swell and strength characteristics of treated soils, which further confirm the particle orientation of the soil on additive amendment. These analyses give a clear understanding of the orientation of the soil fabric, which dominates the overall behaviour of the soil-additive composites.

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Section: X-ray Diffraction Studiesmentioning

confidence: 75%

Section: Swelling Characteristicsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effect of Functional Group of the Inorganic Additives on Index and Microstructural Properties of Expansive Soil

Bhuvaneshwari

Robinson

Gandhi

2020

Int. J. of Geosynth. and Ground Eng.

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“…The extent of swelling depends mainly on geological characteristics and engineering properties (i.e., clay content and mineralogy, water content, Atterberg limits, specific gravity, etc.). Recent studies have shown that the swelling potential of clayey sediments is greatly affected by their geological characteristics (Sarman 1991, Xeidakis 1996, Hossain et al 1997, Shakoor & Sarman 1997). The theoretical model of Shuai and Fredlund (1998) may greatly assist in the prediction of in situ total heave or collapse, the in situ swelling pressure and the rate of swell or collapse of the soils.…”

Section: Introductionmentioning

confidence: 99%

Genesis and Physical Characteristics of the Neogene Red Beds From the Cedarhils of Thessaloniki, Macedonia , Greece

Tsirambides

2018

geosociety

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The genesis and the physical characteristics of the Neogene red beds of the cedar hills surrounding Thessaloniki are studied in this paper. The peri-urban forest, which covers these hills, has a 3,022 ha area. The topographic relief is smooth and is divided in eight small drainage basins, tapped through small creeks. The elevation of the surrounding hills varies between 85 and 560 m. The dominant land slopes vary between 20 and 55%. All the samples are coarse grained, poorly sorted and friable and present earthy lustre and red colour because of the extensive presence of iron oxides. Angular to sub-angular rock fragments derived from the metamorphic bedrock are very common. Petrographically, the studied red beds belong to the clayey sands. The extended presence (41-66%) of coarse silt and sand size grains (>20 pm) in the samples suggests a mild intensity of in situ weathering of the bedrock. X-ray diffraction analysis of the coarsest fractions 250-20 pm and 20-2 μιτι revealed in decreasing abundance the presence of quartz, feldspars, epidote, micas, chlorite, pyroxenes, amphiboles, and talc. These fractions contain the 2M polytype of mica, while in the fraction <2 pm the 1Μα polytype of illite predominates. In the clay fraction (<2 pm) illite, smectite, and chlorite predominate. The presence of mixed-layer minerals is limited, testifying the almost complete character of hydrolysis of the primary minerals. The formation of red beds took place on low relief land under alternating wet and dry seasons, which prevail in the eastern Mediterranean region since Neogene. The clay minerals are the in situ weathering products of the primary minerals of the greenschists, gneisses and gabbros predominating in the studied area. The extensive presence of clay size grains (11-26%) in the samples, their poor sorting, and their sub-angular morphology, indicate that the red beds are texturally immature. In addition, the abundance of feldspars and Fe-Mg minerals reflects mineralogical immaturity. The low relief and the long-lasting tectonic stability in the Thessaloniki district were essential for the significant thickness of the red beds. The oxygen isotope data of the <0.2 pm fraction (+18.2 to +18.8%o) confirm the pedogenic origin of the clay minerals present. The red beds studied present low plasticity with liquid limit (WÏ) 26.9 to 33.4% and plasticity index (lp) 9.1 to 17.3%. In addition, they have high consolidation index (lc) values (1.03 to 2.28). The swelling potential is low to medium and the activity varies between 0.5 and 1.0. The consolidation and induration degree of the samples analyzed is low, because of the great range of their mineralogical composition and the mild conditions of pressure and temperature to which they have been submitted. The studied red beds are not considered problematic for the foundation of various constructions on them.

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“…Otra forma posible para estabilizar los suelos con sulfatos puede ser la sustitución de los aditivos basados en calcio por otros cationes metálicos, como el magnesio. Xeidakis (1996aXeidakis ( , 1996b demostró que la fijación de Mg(OH) 2 en las capas de arcilla expansiva es más rápida que la de Ca(OH)2, lo que genera también en la floculación de la arcilla. También demostró la capacidad del Mg(OH)2 para aumentar el pH del suelo y la posibilidad teórica de producir geles ligantes a base de Mg.…”

Section: Estabilización De Suelos Con Sulfatosunclassified

Estudio de materiales puzolánicos para construcción sostenible basados en residuos y subproductos

Cobo¹

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Ligantes activados alcalinamente (Alkali-Activated Binders) C Calcio C3A Aluminato tricálcico CAH Aluminato de calcio hidratado CDW Residuo de construcción y demolición (Construction and Demolition Waste) CS Resistencia a compresión (Compressive Strength) CSAH Silicoaluminato de calcio hidratado CSH Silicato de calcio hidratado EBCM Material de construcción basado en tierra (Earth Based Construction Material) FA Ceniza volante (Fly Ash) GGBS Escoria granulada molida de alto horno (Ground Granulated Blastfurnace Slag) H Hidratado (hidrato) HR Humedad Relativa LCA Análisis del ciclo de vida (Life Cycle Analysis) LCIA Evaluación del impacto del ciclo de vida (Life Cycle Impact Assesment) NA Áridos naturales (Natural Agreggates) OMC Contenido de humedad óptimo (Optimum Moisture Content) OPC Cemento ordinario tipo Portland (Ordinary Portland Cement) PC Cemento Portland (Portland Cement) PIB Producto Interior Bruto RA Áridos reciclados (Recycled Aggregates) S Silicio UCS Resistencia a compresión simple (Unconfinated Compressive Strength

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Stabilization of swelling clays by Mg(OH)2. Factors affecting hydroxy-Mg-interlayering in swelling clays

Cited by 24 publications

References 21 publications

Effect of Functional Group of the Inorganic Additives on Index and Microstructural Properties of Expansive Soil

Effect of Functional Group of the Inorganic Additives on Index and Microstructural Properties of Expansive Soil

Genesis and Physical Characteristics of the Neogene Red Beds From the Cedarhils of Thessaloniki, Macedonia , Greece

Estudio de materiales puzolánicos para construcción sostenible basados en residuos y subproductos

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