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In lower exchange capacity clays such as kaolinite, illite and chlorite, hydration does not cause swelling but can generate sufficient osmotic pressure to cause separation of individual clay platelets which, under the influence of flowing liquid, are dispersed into the pore network.
Which are the swelling clays?
The most common swelling clays are smectite and smectite mixtures that create an almost impermeable barrier for fluid flow when they are located in the larger pores of a reservoir rock. In some cases, brines such as potassium chloride [KCl] are used in completion or workover operations to avoid clay swelling.
How do you reduce swelling in clay?
One method to reduce clay swelling is to use salts in drilling fluids. Salts generally reduce the swelling of clays. However, salts flocculate the clays resulting in both high fluid losses and an almost complete loss of thixotropy.
What are the two types of clay swelling?
Two different types of clay minerals were used as coatings on beads and quartz grains: montmorillonite (swelling clay) and kaolinite (non-swelling clay). Montmorillonite is a well-characterized powder from Clay Mineral Society (CMS-SAz-1).
Which clay mineral gives maximum swelling?
1) Illite consists of the basic montmorillonite units but is bonded by potassium ions. 2) This mineral is very stable and does not swell or shrinks largely. 1) This bonding is very weak, and water can enter easily. 2) Thus, this mineral can imbibe a large quantity of water causing swelling.
Why do some soils show the properties of swelling clay?
Due to the physical and chemical properties of some clays (such as the Lias Group) large swelling occurs when water is absorbed. Conversely when the water dries up these clays contract (shrink). The presence of these clay minerals is what allows soils to have the capacity to shrink and swell.
What type of clay has high swelling potential?
Expansive clay is a clay soil that is prone to large volume changes (swelling and shrinking) that are directly related to changes in water content.
Can a saturated clay swell?
During periods of heavy rain, clay holds a large amount of water in its small pore space between particles. Saturated clay soils hold so much water the oxygen is excluded. Clay soil has a high shrink-swell capacity. As the particles shrink they separate and cause cracks, from whisper thin to an inch or more.
How the clay mineralogy affects the swelling shrinkage Behaviour of a clay?
The surface of the clay crystal is electrostatically held to the water molecule. Therefore, it is expected that the clay that attracts more water molecules to the surface will have more plasticity, more swelling/shrinkage and more volume change, depending on the load on it. Thus, water influences clay minerals.
Why does montmorillonite clay swell?
Water sorption is an important characteristic of natural clay particles. Water molecules cause swelling in montmorillonite. This swelling is a result of complex montmorillonite-water interactions between particles and within the particle itself.
Why do clay minerals swell?
Zhou (1995) explains that (1) crystalline swelling occurs when the clays are exposed to concentrated brine or aqueous solutions containing large quantities of divalent or multivalent cations. It is caused by the formation of molecular water layers on the surface of clay minerals.
Do all clays swell?
All clays are susceptible to some shrinkage and swelling due to changes in moisture content. Those with a higher proportion of expansive clay minerals, such as smectite, are even more prone. The depth of shrinkage and swelling is contained by the zone where moisture changes are most likely to occur.
What are the types of clay?
The four types of clay are Earthenware clay, Stoneware clay, Ball clay, and Porcelain. All of them can be used to make pottery, but the end result would differ a lot thanks to their different textures, colors, and flexibilities.
Is illite a swelling clay?
Characterization of Bitumen Modified Swelling Clay Minerals The two distinct types of swelling clay minerals, montmorillonite and Illite-smectite, contained different amounts of carbon after reaction with bitumen followed by cyclohexane bitumen removal.
What type of clay is kaolinite?
Kaolinite is aluminosilicate clay and its layer structure is of the 1:1 type. The basic structural unit of kaolinite consists of one tetrahedral (Si–O) sheet and one octahedral (Al–O) layer; the stoichiometric formula is Al2Si2O5(OH)4 [46].
What minerals are in clay soil?
Clay minerals are composed essentially of silica, alumina or magnesia or both, and water, but iron substitutes for aluminum and magnesium in varying degrees, and appreciable quantities of potassium, sodium, and calcium are frequently present as well.
How can you tell if clay is expansive?
3. Signs of expansive soils Cracked foundation or basement walls. Soil pulled back from foundation in dry seasons. Sloping floors. Spongy floors. Doors and windows that rub or stick. Self-closing or opening doors. Gaps at top, bottom or side of doors. Garage door gaps at bottom corners.
What is a high shrink swell index?
The shrink–swell index of clay refers to the extent certain clay minerals will expand when wet and retract when dry. Soil with a high shrink–swell capacity is problematic and is known as shrink–swell soil, or expansive soil.
Why does clay swell more than sandstone?
clay has a porous property which is greater than the podium property of sandstone.. clay swells more because it has the property to absorb more water than sandstone..
Does clay have high plasticity?
Colloidal clays have higher LL and PL than non-colloidal clays; Sand, gravel and peat have no plasticity, their PL= 0; Silts have plasticity only occasionally, their PL being equal to or slightly greater than 0.The plastic limit (PL) Soil type LL PL Clays 100 45 Colloidal clays 399 46.
What is clay mineral used for?
Besides the pharmaceutical application, clay minerals have been extensively used as excipients in some formulation; as lubricants in manufacturing pills; disintegrants; anticaking and thickening agents; binders and diluents; emulsifiers; and carriers of biologically active molecules for improving drugs bioavailability.
Which clay soil group does not swell when wet?
Pick up the clay soil group which does not swell when wet from the following : A. Montrorillonite group.
How long does it take for clay soil to dry out?
The trick to working clay soil is to select just the right moment as it dries out. In many clay soils, this moment comes about 3 days after a rain or irrigation.
Is clay soil wet or dry?
Clay is often reddish in color, water usually is absorbed into clay slowly, it has a tendency to dry slowly, to clump together (and not want to break apart), and to stick like mad to shoes and gardening implements. It will also tend to crust over and crack when it gets dry. Does this sound like the soil in your garden?.
