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Effects of Mica Content on Engineering Properties of Sand
Author(s) -
Harris W. G.,
Parker J. C.,
Zelazny L. W.
Publication year - 1984
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1984.03615995004800030006x
Subject(s) - mica , composite material , compressibility , materials science , relative density , particle size , mineralogy , grain size , quartz , analytical chemistry (journal) , chemistry , sintering , thermodynamics , chromatography , physics
Sand mixtures with variable weight percentage of mica ( W m ) in a quartz matrix were evaluated to isolate the effects of mica content on compacted density, compressibility, shear strength, and bearing capacity. Maximum compacted density decreased linearly with increasing W m , reflecting the inhibitory effect of platy grains on close‐packing of spheroidal grains. The initial tangent axial compression modulus ( E o ), a reciprocal index of undrained compressibility, decreased logarithmically with increasing W m . The relative effect of W m on E o was greater at higher confining pressures. Shear strength (φ), bearing capacity ( q oh ), and California bearing ratio (CBR) also logarithmically decreased with increasing W m . Curves for E o , φ, q oh , and CBR showed shoulders marking diminishing effects of mica additions beyond mica weight percentages of 10 to 15%. A hypothesis that the curvilinear nature of parameter‐vs.‐ W m relationships is due to the sensitivity of these parameters to mica‐quartz interaction at particle contacts is supported by observed linearity between the parameters and mica cleavage face area (MFA). The latter is indexed by mica frequency per 100 grains ( F m ) measured by petrographic grain count on a specific size fraction. If the range of mica grain thicknesses is small relative to the range of diameters, then F m for a single size fraction effectively approximates the MFA for the mica over the whole particle size range. Mica effects on certain engineering properties may be indexed more effectively by F m than by W m .