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4
CH3041
CLAY SWELLING
• Ca2+, Mg2+ hold clay
particles together and
these low ESP clays have good structure.
these low ESP clays have good structure.
• Soils high in
exchangeable Na+ are predisposed towards swelling, surface crusting,
erosion ie. they are problem soils.
• A soil with high ESP and low conductivity ,
eg. Na+-clay forms a colloidal dispersion as swelling allows the individual clay particles to separate and disperse readily in water.
eg. Na+-clay forms a colloidal dispersion as swelling allows the individual clay particles to separate and disperse readily in water.
• Swelling
is driven by exchange cation hydration and osmotic pressure.
