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Title: Effect of wet-dry cycling on swelling and hydraulic conductivity of GCLs

Abstract

Atterberg limits, free swell, and hydraulic conductivity tests were conducted to assess how wet-dry cycling affects the plasticity and swell of bentonite, and the hydraulic conductivity of geosynthetic clay liners (GCLs) hydrated with deionized (DI) water (pH 6.5), tap water (pH 6.8), and 0.0125-M CaCl{sub 2} solution (pH 6.2). The plasticity of bentonite hydrated with DI water increased during each wetting cycle, whereas the plasticity of bentonite hydrated with tap water and CaCl{sub 2} decreased during each wetting cycle. Wet-dry cycling in DI water and tap water had little effect on swelling of the bentonite, even after seven wet-dry cycles. However, swelling decreased dramatically after two wetting cycles with CaCl{sub 2} solution. Hydraulic conductivity of GCL specimens remained low during the first four wetting cycles ({approximately}1 x 10{sup {minus}9} cm/s). However, within five to eight cycles, the hydraulic conductivity of all specimens permeated with the 0.0125-M CaCl{sub 2} solution increased dramatically, to as high as 7.6 x 10{sup {minus}6} cm/s. the hydraulic conductivity increased because cracks, formed during desiccation, did not fully heal when the bentonite rehydrated. In contrast, a specimen continuously permeated for 10 months with the 0.0125-M CaCl{sub 2} solution had low hydraulic conductivity ({approximately}1 x 10{sup {minus}9}more » cm/s), even after eight pore volumes of flow.« less

Authors:
;
Publication Date:
OSTI Identifier:
20006288
Resource Type:
Journal Article
Journal Name:
Journal of Geotechnical and Geoenvironmental Engineering
Additional Journal Information:
Journal Volume: 126; Journal Issue: 1; Other Information: PBD: Jan 2000; Journal ID: ISSN 1090-0241
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 54 ENVIRONMENTAL SCIENCES; SANITARY LANDFILLS; LINERS; SWELLING; HYDRAULIC CONDUCTIVITY; BENTONITE; PLASTICITY

Citation Formats

Lin, L C, and Benson, C H. Effect of wet-dry cycling on swelling and hydraulic conductivity of GCLs. United States: N. p., 2000. Web. doi:10.1061/(ASCE)1090-0241(2000)126:1(40).
Lin, L C, & Benson, C H. Effect of wet-dry cycling on swelling and hydraulic conductivity of GCLs. United States. doi:10.1061/(ASCE)1090-0241(2000)126:1(40).
Lin, L C, and Benson, C H. Sat . "Effect of wet-dry cycling on swelling and hydraulic conductivity of GCLs". United States. doi:10.1061/(ASCE)1090-0241(2000)126:1(40).
@article{osti_20006288,
title = {Effect of wet-dry cycling on swelling and hydraulic conductivity of GCLs},
author = {Lin, L C and Benson, C H},
abstractNote = {Atterberg limits, free swell, and hydraulic conductivity tests were conducted to assess how wet-dry cycling affects the plasticity and swell of bentonite, and the hydraulic conductivity of geosynthetic clay liners (GCLs) hydrated with deionized (DI) water (pH 6.5), tap water (pH 6.8), and 0.0125-M CaCl{sub 2} solution (pH 6.2). The plasticity of bentonite hydrated with DI water increased during each wetting cycle, whereas the plasticity of bentonite hydrated with tap water and CaCl{sub 2} decreased during each wetting cycle. Wet-dry cycling in DI water and tap water had little effect on swelling of the bentonite, even after seven wet-dry cycles. However, swelling decreased dramatically after two wetting cycles with CaCl{sub 2} solution. Hydraulic conductivity of GCL specimens remained low during the first four wetting cycles ({approximately}1 x 10{sup {minus}9} cm/s). However, within five to eight cycles, the hydraulic conductivity of all specimens permeated with the 0.0125-M CaCl{sub 2} solution increased dramatically, to as high as 7.6 x 10{sup {minus}6} cm/s. the hydraulic conductivity increased because cracks, formed during desiccation, did not fully heal when the bentonite rehydrated. In contrast, a specimen continuously permeated for 10 months with the 0.0125-M CaCl{sub 2} solution had low hydraulic conductivity ({approximately}1 x 10{sup {minus}9} cm/s), even after eight pore volumes of flow.},
doi = {10.1061/(ASCE)1090-0241(2000)126:1(40)},
journal = {Journal of Geotechnical and Geoenvironmental Engineering},
issn = {1090-0241},
number = 1,
volume = 126,
place = {United States},
year = {2000},
month = {1}
}