The effect of micro- and nanosilica on the soil permeability coefficient under cyclic freezing and thawing conditions

Zofia Zięba,Kinga Witek,Jakub Mońka,Z Pilecki,J Dec,H Marcak,J Dubiński

doi:10.1051/e3sconf/20186602004

Zofia Zięba, Kinga Witek + Show 5 more

Open Access

https://doi.org/10.1051/e3sconf/20186602004

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Abstract

The paper presents the analysis of the permeability coefficient of frost-susceptible soil with microsilica (MS) and nanosilica (NS) addition. Tests were performed in a triaxial apparatus in three variants: on pure soil samples, on soil samples with a 5% MS and on soil samples with a 5% NS addition. Because of the frost-susceptible properties of analysed soil, the permeability coefficient was determined on unfrozen samples and on samples after 10 cycles of freezing and thawing. The preliminary test results demonstrated that both microsilica and nanosilica have beneficial properties related to subsoil sealing. These properties are considerably stronger for nanosilica. Also, in all cases, the permeability coefficient increased after 10 cycles of freezing and thawing, but the change trend remained the same. Nanosilica shows particularly good sealing properties in frost-susceptible soils. This confirms that it may be applied as a separate additive, which is not commonly used in engineering practice. Nano particles are usually used to extend the scope of micro additives’ influence. In order to recognise the beneficial influence of analysed additives on soil permeability, the recognition of the changes in microstructure is necessary.

Highlights

The key factor affecting the suitability of soil for development is its geotechnical parameters
The contents of individual additives and methods for their mixing with soil were determined in the case of microsilica based on Kalkan's test results [18], and in the case of nanosilica based on Seyedi Gelsefidi and Mamaghanian's paper [16], as well as Bahmani and others’ [10]
The tests carried out allowed for the preliminary recognition of the effect of micro- and nanosilica on the process of water flow in frost-susceptible soils

Summary

Introduction

The key factor affecting the suitability of soil for development is its geotechnical parameters. In order to reduce the susceptibility of soils to freezing processes, various improvement methods are used [3, 4]. The frost heave of soils is closely related to the formation of ice lenses, which increase due to the freezing of migrating water [5, 6]. Water movement through the porous medium is a complex issue that depends on many factors, including its microstructure [7].

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