Thixotropic Changes with Aging of Synthetic Soil Aggregates
1970
Blake, G. R. | Gilman, R. D.
Artificially prepared aggregates held at constant water content increased in relative stability with time. The increase is analogous to a thixotropic sol-gel transformation and to an increase in strength of packed soil with aging. Aggregates were not perceptibly stable to wet sieving at time of formation. Matrix stability of aggregates increased at a rate dependent on water content at which aggregates were stored, on soil type and on storage temperature. High relative stabilities were commonly attained in 24–48 hours at intermediate water contents and at 25C. Extent of slaking resistance was dependent on aging from time of aggregate formation rather than from time of wetting pulverized soil in preparation for pressing into aggregates. The aging phenomenon was independent of organic matter content and of a viable microflora. Data are compatable with the explanation that orientation of water molecules and associated cation equilibrium, and spontaneous shifting of clay particles to positions of lowered potential energy account for the build-up in aggregate stability during aging.
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