Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)

Bibliographic Details
Main Author:	Vera Brown, Benjamin William
Language:	English
Published:	The Ohio State University / OhioLINK 2017
Subjects:	Civil Engineering
Online Access:	http://rave.ohiolink.edu/etdc/view?acc_num=osu1503227150304075

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spelling	ndltd-OhioLink-oai-etd.ohiolink.edu-osu15032271503040752021-08-03T07:03:57Z Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG) Vera Brown, Benjamin William Civil Engineering Bentonite coated gravel (BCG) is a relatively new material that can be used in many applications ranging from pond construction, flood mitigation, well-sealant and grouts, dam/berm construction, wetland restoration, anti-seep collars, trench dams, slope stabilization, temporary and diversion dams, landfill liners, and many other applications. It is a versatile material when an impermeable (or very low permeability) layer needs to be installed or constructed. BCG is coarse aggregate that has been coated with bentonite (using cellulosic polymer as a binder) allowing the material to hydrate and create a low permeability layer as it hydrates, making it very useful when free water is available. There is a wealth of knowledge on similar materials used as landfill liners such as compacted clay liners and sand bentonite liners but since bentonite coated gravel is still a relatively new material for landfill liners, there is a great deal to learn about BCGs and their response to the environments in which they are placed. This study was carried out because little or no information is available in literature if cyclic/dynamic loading impacts its low permeable properties. The main objective of this research is to determine the ability of BCGs to retain their original low hydraulic conductivity during cyclic loading. In order to examine this specific material property, the hydraulic conductivity at cyclic intervals of loading was compared with the initial hydraulic conductivity before cyclic loading was applied. Three separate mixes of varying bentonite (15%, 20%, & 30%) to coarse aggregate (85%, 80%, & 70%) contents, were prepared and tested in triaxial cells for cyclic testing. Each sample was agitated by subjected it to up to 600 cycles at 1% axial cyclic strain and 2% axial cyclic strain for up to an additional 600 cycles. The hydraulic conductivity was measured every 200 cycles. Testing the samples at two different cyclic axial strains (1% and 2%) allowed for a study of the impact of the strain level on the sample permeability. The initial hydraulic conductivity was compared with values measured after every 200 cycles. Sample with lower bentonite content (15%) showed no change in hydraulic conductivity with cyclic loading. For the higher bentonite percentage samples (20% and 30%), there was a very small change in hydraulic conductivity but the change was insignificant. Therefore, these higher bentonite mixtures (20% and 30%) indicated negligible increase in hydraulic conductivity with cyclic loading. All recorded hydraulic conductivity measurements remained within the order of 10-9 cm/s. It is concluded that the hydraulic conductivity of bentonite coated gravel is not significantly impacted by cyclic loading in terms of number of cycles (up to 1,200) or the axial cyclic strain level (up to 2%). 2017 English text The Ohio State University / OhioLINK http://rave.ohiolink.edu/etdc/view?acc_num=osu1503227150304075 http://rave.ohiolink.edu/etdc/view?acc_num=osu1503227150304075 unrestricted This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.
collection	NDLTD
language	English
sources	NDLTD
topic	Civil Engineering
spellingShingle	Civil Engineering Vera Brown, Benjamin William Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
author	Vera Brown, Benjamin William
author_facet	Vera Brown, Benjamin William
author_sort	Vera Brown, Benjamin William
title	Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
title_short	Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
title_full	Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
title_fullStr	Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
title_full_unstemmed	Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)
title_sort	effect of cyclic loading on permeability of bentonite coated gravel (bcg)
publisher	The Ohio State University / OhioLINK
publishDate	2017
url	http://rave.ohiolink.edu/etdc/view?acc_num=osu1503227150304075
work_keys_str_mv	AT verabrownbenjaminwilliam effectofcyclicloadingonpermeabilityofbentonitecoatedgravelbcg
_version_	1719452862514200576

Effect of Cyclic Loading on Permeability of Bentonite Coated Gravel (BCG)

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