International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 05 | May 2025
p-ISSN: 2395-0072
www.irjet.net
A LABORATORY STUDY ON THE EFFICACY OF RICEHUSK ASH AND MAGNESIUM CHLORIDE IN ENHANCING STRENGTH CHARACTERISTICS OF EXPANSIVE SOIL AS A SUBGRADE FOR FLEXIBLE PAVEMENTS Dr. D. Koteswara Rao1, Sajida Sulthana Mohammed2, Sangepu Sairam3 1Professor, Head of The Civil Engineering Department, OSD to Hon’ble Vice Chancellor, University College of
Engineering Kakinada(A), JNTUK, Kakinada, Andhra Pradesh, India
2Assistant Professor(C), Department of Civil Engineering, University College of Engineering Kakinada(A), JNTUK,
Kakinada, Andhra Pradesh, India
3Post graduation Student, Department of Civil Engineering, University College of Engineering Kakinada(A),
JNTUK, Kakinada, Andhra Pradesh, India ---------------------------------------------------------------------***--------------------------------------------------------------------1.Introduction Abstract - Expansive soils, covering nearly one-sixth of India’s land area, are locally known as Black Cotton Soils or Regur. These shrink-swell soils undergo significant volume changes up to 30% due to variations in moisture content, leading to heaving or settlement that can severely damage structures and pavements. In particular, expansive subgrades contribute substantially to road failures. Traditional remedies such as soil replacement and moisture control often face limitations due to high costs or impractical implementation.
Expansive soils are a category of problematic soils characterized by their tendency to undergo considerable volumetric changes in response to moisture fluctuations expanding when saturated and shrinking upon drying. These soil movements can induce substantial structural distress in civil engineering infrastructure, including pavements, foundations, embankments, and utility lines. Found predominantly in arid and semi-arid climatic zones, expansive soils pose significant engineering challenges across the globe.
This study investigation the stabilization of expansive soils using Rice Husk Ash (RHA), an industrial waste, combined with Magnesium Chloride (MgCl₂), a chemical stabilizer. RHA, a by-product of rice milling, is produced in vast quantities in India approximately 20 million tonnes annually. Due to its siliceous nature and impurities, RHA is seldom used in industry and is typically dumped, causing environmental pollution. Utilizing RHA in soil stabilization not only addresses waste disposal challenges but also offers economic and environmental benefits.
In India, these soils are commonly known as Black Cotton (BC) soils, named for their distinctive dark color and historical suitability for cotton cultivation. BC soils cover approximately 20% of the nation’s land area, with major occurrences in the states of Andhra Pradesh, Gujarat, Karnataka, Madhya Pradesh, Maharashtra, and Tamil Nadu. They are especially prevalent throughout the Deccan Plateau, particularly south of the Vindhya Hill range, spanning an estimated 200,000 square miles.
Chemical stabilization using electrolytes like MgCl₂ provides a promising alternative to conventional lime treatment. These chemicals readily dissolve in water, offering a convenient method for soil treatment via ponding or borehole injection, facilitating cation exchange without the need for extensive mixing. This investigation aims to assess the impact of RHA and MgCl₂ on the strength and performance of expansive soils, contributing to more sustainable and cost-effective geotechnical practices.
The highly plastic nature of expansive soils leads to differential heaving and settlement, which severely affects the performance and durability of structures built upon them. These deformations often exceed those predicted by conventional elastic or plastic soil models, rendering traditional geotechnical design approaches inadequate. As a result, infrastructure constructed on expansive soils is prone to cracking, distortion, and premature failure, contributing to substantial maintenance and repair costs.
Keywords: Expansive Soil (ES), Rice Husk Ash (RHA), Magnesium Chloride (MgCl₂), Stabilization, CBR, Plasticity index
Over the years, several mitigation strategies have been developed to address the problematic behaviour of expansive soils. Techniques such as soil replacement, moisture control, pre-wetting, and chemical stabilization with lime or cement have been employed with varying degrees of success. However, each method presents
© 2025, IRJET
|
Impact Factor value: 8.315
|
ISO 9001:2008 Certified Journal
|
Page 1862