Structure and Strength of Artificial Soils Containing Monomineral Clay Fractions.

Grzegorz Jozefaciuk,Kamil Skic,Patrycja Boguta,Krzysztof Lamorski,Agnieszka Adamczuk

doi:10.3390/ma14164688

Grzegorz Jozefaciuk, Kamil Skic + Show 3 more

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https://doi.org/10.3390/ma14164688

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Abstract

Structure and strength are responsible for soil physical properties. This paper determines in a uniaxial compression test the strength of artificial soils containing different proportions of various clay-size minerals (cementing agents) and silt-size feldspar/quartz (skeletal particles). A novel empirical model relating the maximum stress and the Young’s modulus to the mineral content basing on the Langmuir-type curve was proposed. By using mercury intrusion porosimetry (MIP), bulk density (BD), and scanning electron microscopy (SEM), structural parameters influencing the strength of the soils were estimated and related to mechanical parameters. Size and shape of particles are considered as primary factors responsible for soil strength. In our experiments, the soil strength depended primarily on the location of fine particles in respect to silt grains and then, on a mineral particle size. The surface fractal dimension of mineral particles played a role of a shape parameter governing soil strength. Soils containing minerals of higher surface fractal dimensions (rougher surfaces) were more mechanically resistant. The two latter findings appear to be recognized herein for the first time.

Highlights

Soil structure is a unique and important feature governing the development of plants, absorption of nutrients, growth of roots [1], aeration and water transport [2], resistance to erosion [3], and many others features
From the location of the peaks in particle size distributions, one can conclude that the dimension of the dominating particles in the studied minerals increases in the order: goethite, zeolite, illite, montmorillonite and kaolinite
Goethite, having the smallest particles, had the smallest effect on aggregate strength because its particles located on the silt surfaces form fragile, spongy structures

Summary

Introduction

Soil structure is a unique and important feature governing the development of plants, absorption of nutrients, growth of roots [1], aeration and water transport [2], resistance to erosion [3], and many others features. Soil structure and strength are governed primarily by the soil components. A number of reports concern its effect on soil compressibility, void ratio, liquid and plastic limits [15,16,17], specific gravity, bulk density [15,16] and compressive strength [18]. The strong impact of iron oxides, alumina and silica on soil structure and strength was reported as well [19,20,21]. Organic matter, sesquioxides and silica decrease soil strength by increasing soil porosity and reducing bulk density

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