Abstract

Clay soils are known for their water sensitivity, which causes irreparable damage to any structure built on this type of soil. In order to avoid such problem, it is necessary to use various improvement and stabilization methods such as treatment with lime. This process has been used successfully in the field for decades. The addition of lime generates various physicochemical reactions within the soil such as cation exchange and pozzolanic reactions which are largely responsible for the improvement of the soil in question. This paper presents a study concerning the variation of physicochemical properties of clayey soil with the addition of quicklime at different percentages. Experiments were performed on two clayey soils (CL type) in order to investigate the influence of quicklime on Atterberg limits and pH. These tests were carried out in an attempt to study and follow the development and progression of various reactions occurred within the soil with various lime percentages. The results show that the addition of quicklime causes a significant improvement in soil properties by reducing plasticity and thereby improves the soil workability. It can also be found that the addition of lime increase pH of soil, which allow activating pozzolanic reactions who tend to stabilize the soil in question by formation of cementitious compounds. Finally, the pH can be considered as a relevant parameter who allows a better understanding of the reactions that occur in the soil matrix.

Highlights

  • Clayey soils have undesirable properties such as low bearing capacity, high compressibility and dispersive behavior

  • In order to investigate the effect of quicklime on the consistency limits, measures of liquid and plastic limits were carried out on soil samples at different percentages ranging from 0% to 8%

  • This high pH leads the dissolution of the silica and the alumina released from clay minerals, which react with lime creating new cementitious compounds such as calcium silicate hydrates (CSH), calcium aluminate hydrates (CAH) and calcium alumino-silicate hydrates (CASH) as shown in the following equations [42]: Ca2+ + 2(OH) - +SiO2

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Summary

Introduction

Clayey soils have undesirable properties such as low bearing capacity, high compressibility and dispersive behavior. The dissociation reaction of the hydrated lime formed due to the quicklime hydration leads to an increase of the pH and to a high concentration of calcium ions in the pore water [15] These phenomena cause several reactions in the soil matrix, creating a cation exchange effect and pozzolanic reactions [16]. In addition to cationic exchange, the high pH environment induced by lime enables the dissolution of the alumino-silicate constituents of clay minerals, promoting the development of the pozzolanic reactions [15] These reactions result in the formation of calcium silicate hydrate (CSH), calcium aluminate hydrate (CAH), and calcium alumino silicate hydrate (CASH) gels [19,20]. This may help to better understand the interactions occurring within the soil matrix

Samples preparation
Consistency limits tests
Materials
Effect of quicklime on Atterberg limits of soil samples
Effect of lime on pH of soils samples
Conclusion
Full Text
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