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The shrink–swell capacity of soils 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 . [ 1 ]
It has a low shrink–swell capacity and a low cation-exchange capacity (1–15 meq/100 g). Rocks that are rich in kaolinite, and halloysite, are known as kaolin (/ ˈ k eɪ. ə l ɪ n /) or china clay. [9] In many parts of the world kaolin is colored pink-orange-red by iron oxide, giving it a distinct rust hue. Lower concentrations of iron ...
Swelling index may refer to the following material parameters that quantify volume change: Crucible swelling index, also known as free swelling index, in coal assay; Swelling capacity, the amount of a liquid that can be absorbed by a polymer; Shrink–swell capacity in soil mechanics; Unload-reload constant (κ) in critical state soil mechanics
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. [1] Soils with a high content of expansive minerals can form deep cracks in drier seasons or years; such soils are called vertisols.
Vertisols: Usually mollic epipedon; high in shrinking and swelling clays; >30% clay to a depth of 50 cm; deep cracks (called gilgai) form when soil dries; form from parent material high in clay (e.g., shales, basins, exposed Bt horizons of old soils); 2.4% of global and 1.7% of U.S. ice-free land.
These minerals tend to form in sheet or plate like structures, with length typically ranging between 10 −7 m and 4x10 −6 m and thickness typically ranging between 10 −9 m and 2x10 −6 m, and they have a relatively large specific surface area. The specific surface area (SSA) is defined as the ratio of the surface area of particles to the ...
Fed Chair Jay Powell said Wednesday that central bank officials discussed a strategy for how to slow the shrinking of the Fed's balance sheet, a lesser-known policy tool it has been using to ...
Clay minerals can be classified as 1:1 or 2:1. A 1:1 clay would consist of one tetrahedral sheet and one octahedral sheet, and examples would be kaolinite and serpentinite. A 2:1 clay consists of an octahedral sheet sandwiched between two tetrahedral sheets, and examples are talc, vermiculite, and montmorillonite.