Evaluation of Cement Modified Soil (CMS) with Micro-Cracking

Fly ash has been commonly used by KDOT to modify subgrade. Recently, fly ash has become less available and therefore the price has gone up significantly. In addition, a much higher percentage of fly ash needs be used to achieve the same subgrade strength and stiffness than that of cement. Therefore, cement has become more economical for modifying subgrade. However, cement has a major issue of shrinkage cracking, which may result in reflective cracking in asphalt pavements after construction. A high percentage of cement is often needed for some subgrade soils to meet the unconfined compressive strength requirement without jeopardizing durability and stiffness. Higher percentages of cement can result in more shrinkage cracking. To overcome this problem, micro‐cracking technology has been adopted in the field. This technology involves compaction of cement‐modified soil (CMS) and re‐compaction of CMS by a roller 24 to 48 hours later to induce micro‐cracks in the CMS and minimize shrinkage cracking. However, micro‐cracking of CMS is expected to reduce its strength and stiffness but increase its permeability. To verify the performance of CMS with micro‐cracking, an experimental study is proposed which involves laboratory and field tests. During these tests, strength, stiffness, percent of shrinkage, and permeability of CMS before and after micro‐cracking will be evaluated. In addition to conventional laboratory and field test methods, the resistivity method will be adopted to evaluate physical properties of CMS with micro‐cracking.

    Project

    • Status: Active
    • Funding: $32,700
    • Sponsor Organizations:

      University of Kansas, Lawrence

      Department of Civil Engineering, 2006 Learned Hall
      Lawrence, KS  United States  66045-2225
    • Managing Organizations:

      Kansas Department of Transportation

      Eisenhower State Office Building
      700 SW Harrison Street
      Topeka, KS  United States  66603-3754
    • Project Managers:

      Ferguson, Isaac

    • Performing Organizations:

      University of Kansas, Lawrence

      Department of Civil Engineering, 2006 Learned Hall
      Lawrence, KS  United States  66045-2225
    • Principal Investigators:

      Han, Jie

    • Start Date: 20170701
    • Expected Completion Date: 20190630
    • Actual Completion Date: 0

    Subject/Index Terms

    Filing Info

    • Accession Number: 01662456
    • Record Type: Research project
    • Source Agency: Kansas Department of Transportation
    • Files: RiP, STATEDOT
    • Created Date: Mar 8 2018 1:37PM