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- Title
Treating sulfate-bearing soil by using sodium silicate and NaOH-activated ground granulated blast-furnace slag.
- Authors
Li, Wentao; Wang, Jinghao; Chen, Yin; Li, Runxiang; Xiao, Henglin
- Abstract
When calcium-based stabilizers (e.g., lime and cement) are used to treat sulfate-bearing soil, ettringite will be produced under wet conditions, causing swelling of the soil and damage to pavements constructed on sulfate-bearing soils. In order to reduce the swelling of soils caused by ettringite, this study attempted to use the non-calcium-based activators (sodium silicate and NaOH) to activate ground granulated blast-furnace slag (GGBS) to stabilize the sulfate-bearing soil. A series of experiments were carried out: unconfined compression strength, swelling test, leaching test, X-ray diffraction (XRD), and scanning electron microscopy (SEM) tests, to study the performance of soils treated with sodium silicate–NaOH-GGBS. The results showed that the swelling percentage of sodium silicate–NaOH-GGBS-treated soils (0–0.2%) were smaller than that of cement-treated soil (1.2%), and their strengths (1.35–3.35 MPa) were higher than cement-treated soil (0.79 MPa). This was attributed to the formation of ettringite in the cement-stabilized soil after soaking. The calcium ion (Ca2+) concentration in the cement-stabilized soil was higher than that in the sodium silicate–NaOH-GGBS-stabilized soils, and the Ca2+ concentration in the sodium silicate–NaOH-GGBS-stabilized soils kept at a low and stable level. The rapid consumption of Ca2+ in sodium silicate–NaOH-GGBS-stabilized soils for the synthesis of calcium silicate hydrate (CSH) caused the absence of Ca2+ and prevented the production of ettringite. XRD and SEM tests did not detect ettringite in the sodium silicate–NaOH-GGBS-treated soils, which was the reason for insignificant swelling and high strength of the soils. Overall, the sodium silicate–NaOH-GGBS were effective in suppressing swelling due to ettringite and enhancing the strength of sulfate-bearing soils.
- Subjects
SOLUBLE glass; SWELLING soils; CALCIUM silicate hydrate; SLAG; CALCIUM ions; LIME (Minerals); ETTRINGITE
- Publication
Acta Geotechnica, 2024, Vol 19, Issue 5, p3129
- ISSN
1861-1125
- Publication type
Article
- DOI
10.1007/s11440-023-02097-8