SHEAR STRENGTH ENHANCEMENT OF COMPACTED SOILS USING HIGH-CALCIUM FLY ASH-BASED GEOPOLYMER

Authors

  • Soe Thiha
  • Chanodorm Lertsuriyakul
  • Decho Phueakphum

Keywords:

Geopolymer, Curing Period, Cohesion, Friction Angle, Soil Improvement

Abstract

The objective of this study is to experimentally assess the efficiency of geopolymer for the
strengthening of soil material. Geopolymer used in the study is a utilizing of the high-calcium fly-ash (FA)
mixed with sodium hydroxide (NaOH) and sodium silicate (Na2SiO3) as an alkaline activator. The ratio of
NaOH and Na2SiO3 is 1:1. Three types of soils are used and each soil type is mixed with FA based geopolymer
of 10% of dry soil by weight. Alkaline activator is fixed at 10% of optimum moisture content (OMC) of soil
samples. Two conditions of soil sample were prepared for testing; soil samples mixed with fly-ash based
geopolymer and mixed with tap water. They were compacted under the optimum moisture content then
performed the direct shear test to determine the non-curing strength (at 0 days) and curing shear strength (at 7
days). The results indicate that OMC of silty sand and high plasticity silt (sludge) which mixed with fly-ash
based geopolymer is slightly higher than those of sample mixed with tap water. OMC of a clayey soil is
however slightly decreased when they were mixed with fly-ash based geopolymer. Soils mixed with fly-ash
based geopolymer tend to give a higher state of the peak shear strength for curing sample about two times of
soils mixed with tap water. This suggests that the fly-ash based geopolymer can be enhancing the shear strength
of soils by increasing cohesion and friction angle. Soil improvement techniques using geopolymer can be
applied for strengthening the soil embankment, soil slope, and earth dam foundation.

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Published

2018-02-24

How to Cite

Soe Thiha, Chanodorm Lertsuriyakul, & Decho Phueakphum. (2018). SHEAR STRENGTH ENHANCEMENT OF COMPACTED SOILS USING HIGH-CALCIUM FLY ASH-BASED GEOPOLYMER. GEOMATE Journal, 15(48), 1–9. Retrieved from https://geomatejournal.com/geomate/article/view/811