Sorry, I don't understand your search. ×
Back to Search Start Over

The Role of Clay Swelling and Mineral Neoformation in the Stabilization of High Plasticity Soils Treated with the Fly Ash- and Metakaolin-Based Geopolymers

Authors :
Mahmoud A. Mahrous
Branimir Šegvić
Giovanni Zanoni
Suraj D. Khadka
Sanjaya Senadheera
Priyantha W. Jayawickrama
Source :
Minerals, Vol 8, Iss 4, p 146 (2018)
Publication Year :
2018
Publisher :
MDPI AG, 2018.

Abstract

In the southern U.S. states, expansive soils are frequently encountered, presenting an important hazard in geotechnical engineering. This research relies on mineralogical and geochemical clues to explain the swelling behavior of smectite-rich, high-plasticity soils, documented in a series of geomechanical swelling tests that were performed on the soils stabilized with the metakaolin (MKG) and fly ash (FAG) based geopolymers. These geopolymers were mixed with the soil at several concentration levels. The lowest swelling percentage was shown to correspond to the sample stabilized with 12% FAG and was attributed to the neoformation of calcium silicate hydrates that acted as a cementitious material, preventing the soil from expanding by occupying the pore space, thus binding the clay particles together. Conversely, the 12% MKG-stabilized soil exhibited enormous expansion, which was explained by montmorillonite swelling to the point that it gradually began to lose its structural periodicity. The relatively high abundance of the newly formed feldspathoids in MKG-treated samples is believed to have greatly contributed to the overall soil expansion. Finally, the cation exchange capacity tests showed that the percentage of Na+ and Ca2+, as well as the pH value, exercised strong control on the swelling behavior of smectitic soils.

Details

Language :
English
ISSN :
2075163X
Volume :
8
Issue :
4
Database :
Directory of Open Access Journals
Journal :
Minerals
Publication Type :
Academic Journal
Accession number :
edsdoj.96f87d8f71442ce9e94a8f058ff38a7
Document Type :
article
Full Text :
https://doi.org/10.3390/min8040146