EVALUATION OF DIATOMACEOUS EARTH CONTENT IN NATURAL SOILS FOR POTENTIAL ENGINEERING APPLICATIONS
Abstract
Diatomaceous earth is formed by the deposition of biological matter and as such has a number of unique engineering properties. Unique diatomaceous earth?s characteristics include high specific surface area, low dry density, high water storage ability, high friction angle, high compressibility, and unstable response under dynamic loads. These properties came from its biological origin and structure. Due to these peculiar characteristics, diatomaceous earth could be detrimental in some engineering application while it could find application in in the cover of landfills, hydraulic barriers, ionic barriers, low-weight fills, and etc. However to assess potential beneficial properties, engineers and researchers much first completely characterize the material. This characterization must include an estimation of the percentage of diatomaceous earth in the soil and how the diatomite content controls the physical behavior of soils. In this study, the pure diatomaceous earth mixed with kaolinite and silica flour in several proportion was used to assess how parameters such as Atterberg limits, compression tests, and electrical properties change with diatomaceous earth content and how these changes may affect the sue use on diatomic soils in engineering applications.
Experimental results show that diatomaceous earth have high liquid and plastic limits. The higher fraction volume of diatomaceous earth allows higher water storage and that is represented on the results of liquid limit and electrical property test results. The permittivity of diatomaceous earth, kaolinite, and silica flour are governed by the availability of volume of free water in the soil specimens. The higher volumetric water content determines the higher real and imaginary permittivity. In compression tests, as pore fluid drains out with void ratio and volumetric fluid content decrease, the measured permittivity decreased as well. Unbroken microfossil diatom particles with compression load allow higher permittivity than kaolinite and silica flour. Overall, it is shown that the fraction of diatomaceous earth influenced to the physical, mechanical, and electrical properties of soil mixtures. Diatomaceous earth shows different characteristic with silica flour even has same chemical formula and also distinct behavior with clay. It can be told that diatoms should be different classified material with silt and clay. The application of this unique diatomaceous earth should show potential benefit in engineering sight.