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Geomechanics and Engineering
  Volume 25, Number 2, April25 2021 , pages 143-157
DOI: https://doi.org/10.12989/gae.2021.25.2.143
 


Mechanical properties and microstructures of stabilised dredged expansive soil from coal mine
Thanakorn Chompoorat, Suched Likitlersuang, Suwijuck Sitthiawiruth, Veerayut Komolvilas, Pitthaya Jamsawang and Pornkasem Jongpradist

 
Abstract
    Expansive soil is the most predominant geologic hazard which shows a large amount of shrinkage and swelling with changes in their moisture content. This study investigates the macro-mechanical and micro-structural behaviours of dredged natural expansive clay from coal mining treated with ordinary Portland cement or hydrated lime addition. The stabilised expansive soil aims for possible reuse as pavement materials. Mechanical testing determined geotechnical engineering properties, including free swelling potential, California bearing ratio, unconfined compressive strength, resilient modulus, and shear wave velocity. The microstructures of treated soils are observed by scanning electron microscopy, x-ray diffraction, and energy dispersive spectroscopy to understand the behaviour of the expansive clay blended with cement and lime. Test results confirmed that cement and lime are effective agents for improving the swelling behaviour and other engineering properties of natural expansive clay. In general, chemical treatments reduce the swelling and increase the strength and modulus of expansive clay, subjected to chemical content and curing time. Scanning electron microscopy analysis can observe the increase in formation of particle clusters with curing period, and x-ray diffraction patterns display hydration and pozzolanic products from chemical particles. The correlations of mechanical properties and microstructures for chemical stabilised expansive clay are recommended.
 
Key Words
    expansive soil; mechanical properties; microstructure; ground improvement; road material
 
Address
Thanakorn Chompoorat: Department of Civil Engineering, School of Engineering, University of Phayao, Phayao, 56000, Thailand

Suched Likitlersuang and Veerayut Komolvilas: Centre of Excellence in Geotechnical and Geoenvironmental Engineering, Department of Civil Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand

Suwijuck Sitthiawiruth: Department of Civil Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand

Pitthaya Jamsawang: Soil Engineering Research Center, Department of Civil Engineering, King Mongkut's University of Technology North Bangkok, Bangkok 10800, Thailand

Pornkasem Jongpradist: Department of Civil Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
 

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