Effect of groundwater chemistry on the swelling behavior of a Ca-bentonite for deep geological repository

Wen Chuan Chen, Wei Hsing Huang

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

The swelling properties of buffer material for high level radioactive waste repository in a near-field environment are of particular importance for achieving the low permeability sealing function. In this study, the free swelling behavior of a potential buffer material Zhisin clay is evaluated under simulated groundwater conditions such as immersion in NaCl, CaCl2, and Na2SO4 solutions at various concentrations. Experimental results indicate that Zhisin clay, being a Ca-bentonite, exhibits reduced swelling strain in salt solutions. The amount of decrease in swelling strain upon saline water intrusion is affected by both the type and concentration of electrolyte. At the same concentration, the swelling strains in CaCl2 solution are lower than those in NaCl solution due to the quasi-crystals formed in the presence of calcium ions. Also, the swells in Na2SO4 solution are found to be lower than those in NaCl solution. This is attributed to the precipitation of CaSO4, which acts as binding agent and results in aggregation of clay particles.

Original languageEnglish
Pages (from-to)42-49
Number of pages8
JournalPhysics and Chemistry of the Earth
Volume65
DOIs
StatePublished - 2013

Keywords

  • Bentonite
  • Geological repository
  • Groundwater chemistry
  • Swelling

Fingerprint

Dive into the research topics of 'Effect of groundwater chemistry on the swelling behavior of a Ca-bentonite for deep geological repository'. Together they form a unique fingerprint.

Cite this