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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 ]
A free swell test measures the free swell index (FSI) by comparing the volume of dry soil in water to its volume in kerosene. A mineralogical analysis is an X-ray diffraction (XRD) test that can identify specific clay minerals, such as montmorillonite, which would indicate shrink-swell qualities of the soil. [4]
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
Smectite can swell because of the reversible incorporation of water and cations in the interlayer space. The TOT layers are negatively charged because of the isomorphic substitution of Si(IV) atoms by Al(III) atoms in the two external silica tetrahedral layers and because of the replacement of Al(III) or Fe(III) atoms by Mg 2+ or Fe 2+ cations ...
Map of the United States showing what percentage of the soil in a given area is classified as an Ultisol-type soil. The great majority of the land area classified in the highest category (75%-or-greater Ultisol) lies in the South and overlays with the Piedmont Plateau, which runs as a diagonal line through the South from southeast (in Alabama) to northwest (up into parts of Maryland).
The space between this T-O-T sequence of layers is occupied by poorly hydrated potassium cations which are responsible for the absence of swelling. Structurally, illite is quite similar to muscovite with slightly more silicon , magnesium , iron , and water and slightly less tetrahedral aluminium and interlayer potassium .
These equations relate a change in total or water volume (or ) per change in applied stress (effective stress — or pore pressure — ) per unit volume. The compressibilities (and therefore also S s ) can be estimated from laboratory consolidation tests (in an apparatus called a consolidometer), using the consolidation theory of soil mechanics ...
The swelling capacity of a polymer is the amount of a liquid that can be absorbed by it. This test can done by two methods: This test can done by two methods: Beaker test method [ 1 ]