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Stabilization of Phosphatic Clay With Lime Columns



The Florida Institute of Phosphate Research in 1986 funded a one-year laboratory study to investigate the applicability of the lime column method as a stabilization technique for many of Central Florida’s waste phosphate clay deposits. Results indicate that when phosphatic clays are mixed with lime, strength is increased initially due to hydration and with time due to pozzolanic chemical reactions. Similar strength gains were measured on clay mixed with both lime and gypsum, and clay mixed with portland cement, while no strength gain was measured on control samples. Other results of the lab study are as follows: plasticity of the mixes was significantly reduced; deformations as measured by one-dimensional consolidation tests were reduced to one-tenth or less; and permeability was increased about one order of magnitude.