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Advances in Materials Science and Engineering
Volume 2017, Article ID 3181794, 9 pages
Research Article

The Compressibility and Swell of Mixtures for Sand-Clay Liners

Bugshan Research Chair in Expansive Soils, Department of Civil Engineering, King Saud University, Riyadh 11421, Saudi Arabia

Correspondence should be addressed to Muawia A. Dafalla; as.ude.usk@allafadm

Received 1 November 2016; Revised 1 January 2017; Accepted 13 March 2017; Published 10 April 2017

Academic Editor: Aboelkasim Diab

Copyright © 2017 Muawia A. Dafalla. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Sand-clay liners utilize expansive clay to act as a filler to occupy the voids in the sand and thus reduce the hydraulic conductivity of the mixture. The hydraulic conductivity and transfer of water and other substances through sand-clay mixtures are of prime concern in the design of liners and hydraulic barriers. Many successful research studies have been undertaken to achieve appropriate mixtures that satisfy hydraulic conductivity requirements. This study investigates compressibility and swelling properties of mixtures to ensure that they were acceptable for light structures, roads, and slabs on grade. A range of sand-expansive clay mixtures were investigated for swell and compression properties. The swelling and compressibility indices were found to increase with increasing clay content. The use of highly expansive material can result in large volume changes due to swell and shrinkage. The inclusion of less expansive soil material as partial replacement of bentonite by one-third to two-thirds is found to reduce the compressibility by 60% to 70% for 10% and 15% clay content, respectively. The swelling pressure and swell percent were also found significantly reduced. Adding less expansive natural clay to bentonite can produce liners that are still sufficiently impervious and at the same time less problematic.