Hydraulic and mechanical behaviour of cement-bentonite mixtures containing HYPER clay: impact of sulfate attack

Di Emidio, Gemmina;Verástegui Flores, Ramiro Daniel;Scipioni, Claudia;Fratalocchi, Evelina;Bezuijen, Adam
(2015) Sixth International Symposium on Deformation Characteristics of Geomaterials (IS-Buenos Aires 2015) — Location: Buenos Aires, Argentina (15.November.2015)

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Authors
  • Di Emidio, GemminaUGent
    Author
  • Verástegui Flores, Ramiro DanielUCLouvain
    Author
  • Scipioni, ClaudiaUGent
    Author
  • Fratalocchi, EvelinaUPM
    Author
  • Bezuijen, AdamUGent
    Author
Abstract
Cemented clays are regularly employed as cut-off walls to isolate polluted soils or in ground improvement technologies. The objective of this research was to evaluate the performance of a polymer-treated bentonite (HYPER clay) and its impact on hydraulic and mechanical properties of cement-bentonite (CB) mixtures in contact with sulfates. In this research, bender elements were installed in a hydraulic conductivity cell, to simultaneously monitor the small- strain shear modulus (G0) and the hydraulic conductivity (k) of cement-bentonite mixtures. Initially, during permeation with deionized water, an increase of G0 with time was observed, due to cement hydration (hardening). Conversely, after prolonged permeation with sulfates, a decrease of G0 and a gradual increase of k are expected due to degradation of the cemented material. Preliminary results show that k of mixtures containing untreated bentonite increases due to contact with sulfates; conversely, k of mixtures containing HYPER clay remains unaffected. The stiffness modulus G0 was not significantly affected after a sulfate contact period of about 100 days in none of the cement-bentonite mixtures. More extensive monitoring is required for evaluating long-term mechanical degradation. These observations suggest that the use of polymer-treated bentonites could improve the resistance of cement-bentonite mixtures to sulfate attack maintaining a low hydraulic conductivity.
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Di Emidio, G., Verástegui Flores, R. D., Scipioni, C., Fratalocchi, E., & Bezuijen, A. (2015). Hydraulic and mechanical behaviour of cement-bentonite mixtures containing HYPER clay: impact of sulfate attack. Proceedings of Sixth International Symposium on Deformation Characteristics of Geomaterials, p. 1002-1009. https://doi.org/10.3233/978-1-61499-601-9-1002