scholarly journals Insights into Desiccation and Self-Healing of Bentonite in Geosynthetic Clay Liners under Thermal Loads

2019 ◽  
Vol 92 ◽  
pp. 03006
Author(s):  
Abbas El-Zein ◽  
Bowei Yu ◽  
Ali Ghavam-Nasiri
Keyword(s):  
Hydraulic Conductivity ◽  
Mechanical Model ◽  
Thermal Gradients ◽  
Self Healing ◽  
Transient Phase ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Sodium Bentonite ◽  
Mechanical Loads ◽  
Numerical Investigations

Geosynthetic Clay Liners (GCLs) are widely used for protecting groundwater from pollution sources at the surface, including applications in which they are subject to significant thermal gradients. Hence, sodium bentonite in the GCL may undergo significant dehydration and cracking, and the GCL might fail as a result. The paper presents outcomes of a set of recent experimental and numerical investigations exploring the propensity of bentonite to desiccate and self-heal, as well as means of mitigating the effect of thermal gradients on the hydraulic conductivity of GCLs. An elasto-plastic thermo-hydro-mechanical model was found to yield reasonable predictions of experimental behaviour, except for the transient phase of pre-heating hydration. Introducing an airgap between the GCL and the heat source can reduce the extent of desiccation and its effects on hydraulic conductivity. However, the effectiveness of the solution will depend on other factors including subgrade, magnitude of thermal and mechanical loads and type of GCL.

scholarly journals Laboratory investigation of self-healing properties on geosynthetic clay liners with flaw

2015 ◽  
Vol 41 (1) ◽  
pp. 53-58 ◽  
Author(s):  
Guang-Wei Zhang ◽  
Hu-Yuan Zhang ◽  
Jin-Fang Wang ◽  
Lang Zhou ◽  
Ping Liu ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
The Self ◽  
Distilled Water ◽  
Self Healing ◽  
Test Results ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Order Of Magnitude ◽  
Flexible Wall ◽  
Research Findings

Abstract The objective of this paper is to evaluate the self- healing properties of a commercially-available geosynthetic clay liner (GCL) using flexible-wall permeameter. The GCLs are produced by the same factory, but the contents of bentonite are different. Also the hydraulic conductivities (HC) of GCLs with no defect are different. In this study, specimens were completely saturated under the backpressure of 20 kPa before the test. Permeability tests were performed on GCL specimens with penetrating flaw and also on specimens permeated with distilled water and CaCl2 solutions. The test results were presented and discussed. Experimental results showed that the GCL with penetrating flaw did not exhibit complete self-healing in the case of flaw. After 120 days, the hydraulic conductivity increased by approximately an order of magnitude. In addition, CaCl2 solutions had a significant influence on the hydraulic conductivity. The research findings might be of interest to researchers and engineers who design liners for landfills and other liquid containment facilities

Effect of incineration ash leachates on the hydraulic conductivity of bentonite-polymer composite geosynthetic clay liners

2022 ◽  
Vol 139 ◽  
pp. 25-38
Author(s):  
Christian Wireko ◽  
Tarek Abichou ◽  
Kuo Tian ◽  
Binte Zainab ◽  
Zhiming Zhang
Keyword(s):  
Hydraulic Conductivity ◽  
Polymer Composite ◽  
Geosynthetic Clay Liners ◽  
Clay Liners

Insight into hydraulic conductivity testing of geosynthetic clay liners (GCLs) exhumed after 5 and 7 years in a cover

2017 ◽  
Vol 54 (8) ◽  
pp. 1118-1138 ◽  
Author(s):  
R.K. Rowe ◽  
R.W.I. Brachman ◽  
M.S. Hosney ◽  
W.A. Take ◽  
D.N. Arnepalli
Keyword(s):  
Hydraulic Conductivity ◽  
Unit Area ◽  
Divalent Cations ◽  
Hydraulic Gradient ◽  
Silty Sand ◽  
Geosynthetic Clay Liners ◽  
Clay Liners ◽  
Percentage Area ◽  
Bundle Size ◽  
Insight Into

Four geosynthetic clay liners (GCLs) serving as single liners were exhumed from below 0.7 m of silty sand on a 3:1 (horizontal:vertical) north-facing slope at the QUELTS site in Godfrey, Ontario, after 5 and 7 years. The 300 mm GCL overlaps with 0.4 kg/m supplemental bentonite were all physically intact. The exchangeable bound sodium was completely replaced with divalent cations. The GCL with the smallest needle-punched bundle size (average of 0.7 mm) and percentage area covered by bundles (4%) maintained low hydraulic conductivity (k) when tested under 0.07–1.2 m head with 10 mmol/L CaCl2 solution as the permeant. For GCLs with larger bundles (1.1–1.6 mm) and higher percentage area covered by bundles (9%–14%), k was low when the head was low (0.07 m). Once the applied head increased, k increased by 1–4 orders of magnitude depending on the (i) hydraulic gradient, (ii) size and number of the needle-punched bundles, and (iii) structure and mass of the bentonite per unit area. The results suggest that the GCLs can perform effectively as a single hydraulic barrier in covers providing that the head above the GCL is kept low (e.g., by a suitable drainage layer above the GCL).

Self-Healing Properties of Geosynthetic Clay Liners

2001 ◽  
Vol 8 (5) ◽  
pp. 461-470 ◽  
Author(s):  
G.L. Sivakumar Babu ◽  
H. Sporer ◽  
H. Zanzinger ◽  
E. Gartung
Keyword(s):  
Self Healing ◽  
Geosynthetic Clay Liners ◽  
Clay Liners
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