The classification of microstructures of clay soils

Abstract

This paper presents the results of experimental studies on the microstructure of clay soils, using scanning electron microscopy. Approximately 300 samples of clay soils of various ages, origin and degree of lithifiation have been analysed. Five main types of microstructure have been identified in clay soils of sedimentary origin, i.e. honeycomb, skeletal, matrix, turbulent and laminar. Among clay soils of sedimentary origin and hydrothermal origin three types of microstructure were distinguished; domain, pseudoglobular and globular.In natural environments, microstructures of mixed features have been found, i.e. honeycomb-matrix, honeycomb-skeletal, turbulent-matrix, etc.The detailed description presented of the different microstructural types comprising morphology and quantitative calculations, shows a close relationship with mineral composition, origin and degree of lithifiation.In addition physical and mechanical properties as well as the resistance and deformation indices of clay soils have been found to be related to microstructural features.Microstructure is one of the most important factors determining the properties of clay soils. Tenaghi (1925) was the first to pay attention to the necessity of studying the clay microstructure. During the ensuing years many investigators were engaged in microstructural studies : and others. However, up to now, clay microstructures have not been adequately studied. One of the main reasons for this is the high dispersity of clay soils, which calls for high magnifications when studies are conducted at the microlevel. Therefore, in spitebf the fact that a number of interesting investigations have been performed with the help of light microscopes, many specific microstructural features of clays remained inaccessible for comprehensive studies. Only the recent advent of the scanning and transmission electron microscopes have made such investigations possible. Beginning in 1968 the

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“…10). The particle arrangement locally displays an open honeycomb structure ( sensu Sergeyev et al. , 1980; Fig.…”

Towards understanding the microstructural and structural changes in natural hierarchical materials for energy recovery: In-operando multi-scale X-ray scattering characterization of Na- and Ca-montmorillonite on heating to 1150 °C

“…6 While various studies have investigated the microstructures 7,8,9,10,11–14 or the crystal structures of clays 15,16,17 there remains a limited scientific understanding of how changes at the nano-scale impact the microstructural properties, or vice versa.…”

The changes in the microstructure of ion-exchanged clays

“…clay fraction affect to their engineering parameters [1]. Also, connections between the type of exchangeable cation and soil mechanical properties [2,3] and changes in microstructural parameters [4,5] are confirmed. Despite this, looking for the connections between the microstructure features with the soil properties is very essential.…”