To Study the Impact of Chloride Compounds on the Characteristics of Clay Soil

Abstract

This study investigates the impact of chloride compounds (CaCl2, MgCl2 and NaCl) on clay soil, aiming to provide valuable insights into the behavior and potential consequences of introducing chloride-based materials into clay-rich soil. Clay soils are prevalent in various regions worldwide and are known for their unique properties, including high plasticity and low permeability. Understanding how chloride compounds interact with clay soils is crucial for numerous fields, including geotechnical engineering, environmental science, and agriculture. The research involved laboratory experiments on clay soil samples added with varying concentrations (1%, 3%, and 5%) of chloride compounds (CaCl?, MgCl?, NaCl). Tests assessed physical and chemical changes in the soil, including consistency limits, optimum moisture content, maximum dry density, and unconfined compressive strength. Results showed that increasing chloride concentration led to a decrease in liquid limit, plastic limit, plasticity index, and optimum moisture content. Conversely, maximum dry density and unconfined compressive strength increased. Where, CaCl? consistently produced the greatest improvement in strength and reduction in plasticity, while NaCl had the mildest effect. These findings are relevant for both soil stabilization practices and understanding the environmental impact of saline intrusion.

Introduction

Clay soils present challenges in construction due to their expansive behavior, high plasticity, and low strength. Chemical stabilization using chloride salts—specifically sodium chloride (NaCl), calcium chloride (CaCl?), and magnesium chloride (MgCl?)—is a cost-effective method to improve these geotechnical properties. This research investigates the effects of adding these salts at 1%, 3%, and 5% concentrations (by dry weight) to clay soil, aiming to understand their impact on soil physical, chemical, and strength characteristics.

The study addresses gaps in existing literature, which is limited and fragmented regarding the combined effects of chloride compounds on clay soil behavior and their long-term environmental consequences. Laboratory tests include Atterberg limits, compaction, and unconfined compressive strength on untreated and salt-treated samples.

Soil samples were collected from a site in Lucknow, India, classified as high plasticity clay (CH), with significant clay content (77.8%) and notable swelling potential. Chloride salts were dissolved in water and mixed with the soil before specimen preparation using standard compaction procedures.

The research aims to provide comprehensive insights into how different chloride salts and their concentrations modify clay soil properties, guiding more sustainable and effective stabilization practices.

Conclusion

An extensive experimental analysis has been performed to study the effect of Chloride Compound (i.e. CaCl2, MgCl2 and NaCl) on clay soil after mixing in different proportions. Based on the experimental data collected and analyzed for the soil, soil mixed with Chloride compound at 1%, 3%, and 5% by weight of dry soil. Based on detailed discussions ,the following main conclusions may be drawn as given below: A. For Native Soil 1) The soil is classified as CH i.e. clay having high plasticity with Plasticity Index and Specific gravity as 26.44% and 2.65 respectively. 2) The OMC ,MDD and Unconfined Compressive strength values are obtained experimentally are 19.12% ,1.780 ,and 1.750 g/cm2 B. For the Soil Mixed with Calcium Chloride (CaCl2) 1) It is seen that in case of 1% CaCl2, Plasticity Index, and OMC, is decreased from 26.44% and 19.12% respectively to 24.92%, and 17.01% respectively. While the MDD and Unconfined compressive strength increase from 1.780 gm/cc and 1.750 g/cm2 respectively to 2.03 g/cc and 1.95 g/cm2 respectively. 2) In case of 3% CaCl2, Plasticity Index, and OMC, is decreased from 26.44% , and 19.12% respectively to 23.45%, and 14.41% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 2.33 g/cc and 2.20 g/cm2 respectively. 3) In case of 5% CaCl2, Plasticity Index, and OMC, is decreased from 26.44%, and 19.12% respectively to 21.93%, and 11.81% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 2.63 g/cc and 2.45 g/cm2 respectively. C. For the Soil mixed with Magnesium Chloride ( MgCl2 ) 1) It is seen that in case of 1% MgCl2, Plasticity Index, OMC, and Free swell index is decreased from 26.44%, 19.12% and 55.02% respectively to 25.44%, 17.62% and 53.04% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 1.93 g/cc and 1.85g/cm2 respectively. 2) In case of 3% MgCl2, Plasticity Index, OMC, and Free swell index is decreased from 26.44%, 19.12% and 55.02% respectively to 24.44%, 15.51% and 50.54% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 2.13 g/cc and 2.00 g/cm2 respectively. 3) In case of 5% MgCl2, Plasticity Index, OMC, and Free swell index is decreased from 26.44%, 19.12% and 55.02% respectively to 23.44%, 13.48% and 48.04% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 2.33 g/cc and 2.15 g/cm2 respectively. D. For the Soil mixed with Sodium Chloride (NaCl) 1) It is seen that in case of 1% NaCl, Plasticity Index, and OMC, is decreased from 26.44%, and 19.12% respectively to 25.94%, and 18.12% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750g/cm2 respectively to 1.88 g/cc and 1.80 g/cm2 respectively. 2) In case of 3% NaCl, Plasticity Index, and OMC, is decreased from 26.44%, and 19.12% respectively to 25.44%, and 16.62% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 1.93 g/cc and 1.90 g/cm2 respectively. 3) In case of 5% NaCl, Plasticity Index, and OMC, is decreased from 26.44% and 19.12% respectively to 24.94%, and 15.12% respectively. While the MDD and Unconfined compressive strength increase from 1.780 g/cc and 1.750 g/cm2 respectively to 2.03 g/cc and 2.00 g/cm2 respectively. ? The purpose of this study was to ascertain how three chloride compounds CaCl2, MgCl2, and NaCl, added to clay soil would affect its characteristics. The soil underwent tests to determine its shear strength, dry unit weight, and shear limit for liquid and plastic. The liquid limit, plastic limit, and plasticity index of the soil were all reduced by the addition of each individual chloride compound. With the percentage of salts increasing, the Maximum dry density increases and the Optimum moisture content decreases. Compounds containing chloride were added to the soil, increasing its compressive strength. Strengthening the soil and enhancing its other qualities may be helped by this. ? On the basis of results among all the three Chloride compound CaCl2 gives the best result to reduce the Plasticity Index, and OMC while increases MDD and Unconfined compressive strength of the clay soil. ? There are many regions in India such as Plateau of Maharashtra, Plateau of Malwa (MP), Uttar Pradesh, Chhattisgarh and extended in South-East direction which contain 20% area of total land area as Expansive Soil (Clay Soil). On the basis of above result we can improve the engineering properties of clay soil which will help us to prevent sudden settlement of structural project.

References

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Copyright

Copyright © 2025 Vikas Gautam, Dr. U.K. Maheshwari, Dr. Bipin Prajapati. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.