Five soil samples were selected to represent the subgrade soils commonly stabilized by lime or cement in NCDOT highway construction. The five soils are classified by the AASHTO symbols A-4, A-4, A-5, A-6, and A-7-5 and were labelled as samples DOT-1 to DOT-5. Laboratory tests measured the CBR, resilient modulus, and unconfined compressive strength on samples compacted in the laboratory at three different water contents for each soil. The five soils were compacted without any additive to measure the soil properties for unstabilized soil. The five soils were then mixed with 3%, 4%, and 5% lime before compacting and with 8%, 10%, and 12% cement before compacting. The lime stabilized soils showed the greatest improvement when mixed with 4% lime as the resilient modulus for four of the samples increased by 3 to 5 times. The A-7-5 soil only increased by 1.5 times. The resilient modulus for the cement stabilized soils increased more but without an optimum cement level for all five soils. For soils DOT-1 to DOT-4 the resilient modulus increased by a factor of 5 to 7 times when mixed with cement. The measured resilient moduli were used in a layered elastic analysis to infer the structural layer coefficients by using the resilient vertical strain in the subgrade as a criteria. The structural layer coefficients for lime stabilized soils varied from 0.06 to 0.18 for base course resilient moduli of 30,000 to 40,000 psi. The structural layer coefficients for the cement stabilized soils were determined from the unconfined compressive strengths and varied from 0.12 to 0.18.

  • Corporate Authors:

    North Carolina State University, Raleigh

    Department of Civil Engineering
    Raleigh, NC  United States  27695-7908

    North Carolina Department of Transportation

    Division of Highways, P.O. Box 25201
    Raleigh, NC  United States  27611

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Lambe, P C
    • Khosla, N P
    • Jayaratne, N N
  • Publication Date: 1990-5

Media Info

  • Features: Appendices; Figures; References; Tables;
  • Pagination: 192 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00616576
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/NC/90-001
  • Contract Numbers: 23241-88-1
  • Created Date: Nov 30 1992 12:00AM