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Mechanisms of concentration control alkali activated fly ash stabilized saline soil in seasonally frozen regions

  • 0State Key Laboratory of Chemistry and Utilization of Carbon Based Energy Resources, College of Chemistry, Xinjiang University, Urumqi, 830017, Xinjiang, People's Republic of China.
Scientific Reports +

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January 2, 2025

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January 2, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

This study enhances sulfate saline soil stability using fly ash geopolymer, optimizing sodium hydroxide concentration for improved frost resistance. The best results were achieved with a 0.5 M concentration, maintaining significant strength after freeze-thaw cycles.

Area Of Science

  • Geotechnical Engineering
  • Materials Science
  • Environmental Science

Background

  • Sulfate saline soils pose stability and frost resistance challenges.
  • Industrial solid waste, like fly ash, offers potential for soil stabilization.
  • Geopolymerization is a promising method for utilizing fly ash in construction materials.

Purpose Of The Study

  • To improve the stability and frost resistance of sulfate saline soil.
  • To investigate the effect of fly ash geopolymer with varying NaOH concentrations on soil properties.
  • To evaluate the microstructure and strength of stabilized soil under freeze-thaw conditions.

Main Methods

  • Fly ash (FA) was activated using sodium hydroxide (NaOH) at concentrations from 0.1 M to 0.9 M.
  • Stabilized soil samples were subjected to unconfined compressive strength (UCS) and splitting strength tests.
  • Microstructural analysis was performed using X-ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR), and Thermogravimetric Analysis (TG).
  • Freeze-thaw tests were conducted over 5 cycles.

Main Results

  • Increased NaOH concentration promoted the growth of FA gel material.
  • Optimum NaOH concentration for strength and frost resistance was found to be 0.5 M.
  • At 0.5 M NaOH, UCS and splitting strength reached 7.18 MPa and 1.89 MPa after 28 days curing.
  • After 5 freeze-thaw cycles, residual UCS and splitting strength were 46.35% and 39.92% of the initial values, respectively.

Conclusions

  • Fly ash geopolymer activated by NaOH is effective in stabilizing sulfate saline soil.
  • An optimal NaOH concentration of 0.5 M maximizes strength and frost resistance.
  • This method provides a sustainable approach to managing industrial waste and improving problematic soils.

Keywords:

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