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Podium Presentation at the Conference

Innovative Sustainable Methods, Materials, and Recycling

Session: Sustainable Construction and Design Solutions Using Cementitious Materials

1369369 - Strengthening of Sandy Soils with Polyelectrolytes

Friday, June 16, 2023
8:45 AM – 9:00 AM CST
Room: 602
TRACK: K

    Primary Author(s)

  • Ardak Makhatova, MSc (she/her/hers)

    Ph.D. Student
    Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA
    College Station, TX, United States

    • Presenter(s)

  • Ardak Makhatova, MSc (she/her/hers)

    Ph.D. Student
    Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA
    College Station, TX, United States

    • Co-Author(s)

  • Svetlana A. Sukhishvili, Ph.D.

    Professor
    Department of Materials Science and Engineering, Texas A&M University, College Station, TX 77843, USA, Texas, United States

  • Eyad Masad, Ph.D., P.E., F. ASCE

    Professor
    Mechanical Engineering Program, Texas A&M University at Qatar, Doha P.O. Box 23874, Qatar
    Doha, Ar Rayyan, Qatar

This work aims to evaluate the potential application of polyelectrolytes such as cationic poly(diallyldimethylammonium chloride) (PDADMAC), anionic polystyrene sulfonate (PSS), and anionic lignosulfonate (LS), to stabilize sandy subgrade soils in Qatar. Several factors, including charge and molecular weight of polymers, and surface charge on the soil particles, were found to influence the binding of polymers with soil particles. The microstructure and composition of the Qatari soils were investigated using scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), and X-ray fluorescence analysis (XRF). Based on the results, the sandy soil in Qatar is mostly composed of carbonates and silicates with a small amount of clay minerals. The effect of the polyelectrolytes and polyelectrolyte complexes (PECs) of different compositions and dosages (from 0.2% to 1.6%) on soil strengthening was investigated. The addition of PDADMAC, PSS, LS, and their complexes resulted in an increase of soils’ unconfined compressive strengths as compared to polymer-free soils. These results were correlated with the rheological properties of polymer-stabilized and non-stabilized soils. Finally, the effect of polyelectrolytes on moisture stability and moisture resistance was studied. Both cationic and anionic polyelectrolytes resulted in improved retention of mechanical properties of soils after multiple wet-dry soil curing cycles as determined in unconfined compressive strength experiments. Nuclear magnetic resonance (NMR) was used to study the water retention capacity of the stabilized and unstabilized soil samples during the wet-dry curing cycles.

Learning Objectives:

Attendees can expect to learn the following from this session:
  • Understand the binding of soils and non-traditional stabilizers such as polymers and the factors that affect this.
  • Define the microstructure and composition of soils.
  • Investigate changes in the microstructure of soils with rheological methods.
  • Conduct unconfined compressive strength experiments and analyze the data obtained.
  • Apply nuclear magnetic resonance technology to study water retention capacity of soils.