Investigation of Hydraulic Conductivity of SHMP Amended Soil-Bentonite Backfills Exposed to Lead-Impacted Groundwater

Jiang, Zhe-Yuan; Zhang, Run; Fu, Xiaonan; Wan, Jia-Lei; Li, Shuangjie; Yang, Yuling; Du, Yao

doi:10.1007/978-3-030-79647-1_1

Cited by 4 publications

(1 citation statement)

References 8 publications

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“…Vertical cutoff walls with excellent hydraulic conductivity have been extensively used to contain contaminated groundwater at worldwide various contaminated sites and landfill sites (municipal solid waste landfill, hazardous waste landfill, and simple landfill et al) [1][2][3]. Vertical cutoff walls serve to intercept pathways of pollution and separate sources of contamination from vulnerable receptors [1,4]. Depending on the composition of backfill materials, they are primarily classified as soil-bentonite (SB), soilcement (SC), cement-bentonite (CB), and soil-cement-bentonite (SCB) [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Engineering Properties of Novel Vertical Cutoff Wall Backfills Composed of Alkali-Activated Slag, Polymer-Amended Bentonite and Sand

Jiang

Shi

et al. 2023

Polymers

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The workability, hydraulic conductivity, and mechanical properties are essential to contaminant containment performance of cementitious backfills in vertical cutoff walls at contaminated sites. This study aims to investigate the engineering properties of a novel vertical cutoff wall backfill composed of reactive magnesia (MgO)-activated ground granulated blast furnace slag (GGBS), sodium-activated calcium bentonite amended with polyacrylamide cellulose (PAC), and clean sand (referred to as MSBS-PAC). Backfills composed of MgO-activated GGBS, sodium-activated calcium bentonite, and clean sand (referred to as MSBS) were also tested for comparison purposes. A series of tests were conducted which included slump test, flexible-wall hydraulic conductivity test, and unconfined compression test. The pore size distributions of two types of backfills were investigated via the nuclear magnetic resonance (NMR) technique. The results showed the moisture content corresponding to the target slump height was higher for MSBS-PAC backfill than that for MSBS backfill. The MSBS-PAC backfill possessed lower pH, dry density, and higher void ratio at different standard curing times as compared to MSBS backfill. The unconfined compressive strength and strain at failure of the MSBS-PAC backfill were noticeable lower than those of the MSBS backfill. In contrast, the hydraulic conductivity of MSBS-PAC backfill was approximately one order of magnitude lower than that of the MSBS backfill, which was less than 10−9 m/s after 28-day and 90-day curing. Lower hydraulic conductivity of MSBS-PAC backfill was attributed to the improvement of pore structure and pore fluid environment by PAC amendment.

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