Comparison of perlite and pumice effects on the geotechnical properties of saline silty soil

ABSTRACT

This research mainly sought to evaluate the sediments of the Urmia lake bed to prevent their erosion and the possibility of improving the problematic saline fine soils in the region by the geo-polymerisation process. For this purpose, perlite and pumice materials, with pozzolanic properties and weight percentages of 3, 5, and 7, were separately mixed with soil, along with the calcium hydroxide (Ca(OH)₂) solution as a catalyst with 2%, 5%, and 7%. Then, the samples were cured for one day. Uniaxial compressive strength (UCS), direct shear, and consolidation tests were performed to assess the geotechnical properties of improved soil compaction. The results revealed that, compared to pumice, perlite could improve the behavioural properties of the studied soil. The inclusion of perlite and pumice, along with calcium hydroxide, increased the flexibility of the stabilised soil, as indicated by the brittleness index. Similarly, combining 3% perlite with 2% Ca(OH)₂ could increase UCS at failure by 3.27 times. In addition, the mixture of 5% perlite with 7% Ca(OH)₂ could enhance the shear strength by 3.3 times. Finally, combining 3% perlite with 5% calcium hydroxide reduced the swelling of the improved soil by 82%, and the consolidation settlement was decreased by 64% on average.

Highlights

1. Sodium saline silty soil can cause many problems, such as settlement and swelling in ground and underground structures.

2. The present research investigated the effects of perlite and pumice materials and calcium hydroxide as a catalyst on improving saline silty soil.

3. The results revealed that perlite is more effective than pumice because of its pozzolanic properties. As a result of mixing perlite with saline silty soil along with calcium hydroxide, after curing, the skeleton of the soil particles changed from fine to coarse grains, modifying the characteristics of the soil.

KEYWORDS:

• Fine soil
• saline
• sodium
• perlite
• pumice
• improvement

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data generated or analysed during this study are included in the present article (and its supplementary information files).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/17486025.2024.2350499

Additional information

Funding

The authors declare that they have received no funding to perform this research.