Mechanical behavior of soil–diatom mixtures incorporating bilaterally symmetric diatom species

Diatomaceous soils exhibit uncommon properties, such as high liquid limits and high friction angles. This counterintuitive behavior has generated interest in the geotechnical field. Understanding the relationship between macroscopic behavior and diatom characteristics in fine soil mixtures is essential for assessing the influence of diatom shape on mechanical performance. This study contributes to the understanding of diatomaceous soils by comparing an elongated, bilaterally symmetric species ( Epithemia gibberula ) with a compact, radially symmetric species ( Discotella Pseudostelligera ). The comparison is based on consistency limits, consolidation, and shear strength. The results suggest a link between diatom shape and the mechanical behavior of the mixtures. Elongated diatoms tend to fracture more easily, which reduces interparticle interlocking and results in lower shear resistance and higher compressibility compared to disc-shaped diatoms. Nanoporosity was assessed using the BET method for Epithemia gibberula , revealing a high concentration of nanopores that may contribute to its mechanical response. In addition, the study incorporates diatoms from Cotopaxi, Ecuador, a region rarely reported in the literature, helping to expand the geographical scope of research on diatomaceous soils.