OEDOMETRIC BEHAVIOR OF SOIL-DIATOM MIXTURES BEFORE FRUSTULE CRACKING

Abstract

The aim of this research is the characterization of the effects of diatom content on the consolidation of soil-diatom mixtures before the breakage of frustule particles. Results of implemented laboratory tests that characterized the compressibility of soil mixtures made of fine-grained soil and Cyclotella Distinguenda diatoms were analyzed to define the physical properties of specimens including water content by mass, Casagrande test, specific gravity, and grain size distribution. Moreover, the compressibility was evaluated using a one-dimensional oedometer test. The compressibility index of the samples decreased as the diatom content increased. Additionally, the coefficient of consolidation increases at higher diatom contents, leading to a faster process of pore water dissipation. Regarding those two parameters, this behavior is associated with a higher diameter of diatom particles when compared to clay soils. This bigger diameter influences the frictional characteristic of the soil samples, giving them sand-like properties for low confinement pressures. Indeed, the compressibility index decreases from 0.27 with a diatom content of 0% to 0.08when the diatom content are 60%. The tests evaluated the properties of soil-diatom mixtures with uncracked frustules showing a different behavior when compared to oedometer reports of diatom-soil mixtures.