Chemical Modification of Uniform Soils and Soils with High/Low Plasticity Index

The addition of chemicals into the subgrade has been widely used during construction to improve the soil properties. The chemicals, often Lime Kiln Dust (LKD) and Portland cement, are added to the soil to improve its workability, compactability and engineering properties. Many departments of transportation (DOTs) have been using chemical modification for more than 20 years. In fact, 90% of the current subgrade is treated. Despite the wide experience-based in treating subgrade soils, several problems still exist. The Indiana Department of Transportation (INDOT) design manual states that subgrade clays with low plasticity (PI< 10) must be treated with cement and that high plasticity clays (Density < 95 pcf, or PI ≥ 25) in the subgrade must be replaced with suitable soils. Uniform granular soils do not stabilize with lime products or with low dosage of cement. Current knowledge does not provide information about stabilization of these soils. This research explores LKD, combinations of LKD and Portland cement to treat high and low plasticity clayey soils (problem soils, e.g. expansive and organic soils are not considered in the research) and treatment with Portland cement of uniform granular soils. A comprehensive laboratory testing program has been undertaken to investigate the potential for the treatment and to report the changes in mineralogy and engineering properties of the treated soils with time. Unconfined compression tests performed over time, as well as XRD tests, show that treatment is possible and that it remains over time since the strength of the treated soil improves with time and its mineralogy does not change.

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    Purdue University

    Joint Transportation Research Program
    West Lafayette, IN  United States  47907-2051

    Indiana Department of Transportation

    State Office Building
    100 North Senate Avenue
    Indianapolis, IN  United States  46204

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Tao, Fei
    • Li, Xuanchi
    • Bobet, Antonio
    • Siddiki, Nayyar Zia
  • Publication Date: 2016-8


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Photos; References; Tables;
  • Pagination: 32p

Subject/Index Terms

Filing Info

  • Accession Number: 01634602
  • Record Type: Publication
  • ISBN: 9781622604517
  • Report/Paper Numbers: FHWA/IN/JTRP‐2016/32
  • Contract Numbers: SPR‐3940
  • Created Date: Mar 31 2017 11:24AM