Using MgO activated slag and calcium bentonite slurry to produce a novel vertical barrier material: Performances and mechanisms

Huang, Xiao; Li, Jiangshan; Guo, Ming-Zhi; Xue, Qi‐Kun; Du, Yong; Wan, Yong; Liu, Lei; Poon, Chi Sun

doi:10.1016/j.conbuildmat.2021.123365

Cited by 16 publications

(1 citation statement)

References 53 publications

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“…Currently, cut-off walls are a popular geotechnical engineering method to remediate contaminated sites [6][7][8]. Soil-bentonite (SB) and cement-bentonite (CB) cut-off walls are widely used worldwide to retard the movement of groundwater and the migration of contaminant plumes by cutting off the flow of groundwater [9,10]. The currently available research on these two materials has focused on their permeability properties [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Engineering Characteristics and Microscopic Mechanism of Soil–Cement–Bentonite (SCB) Cut-Off Wall Backfills with a Fixed Fluidity

Zhou

Liu

et al. 2023

Materials

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Soil–cement–bentonite (SCB) backfill has been widely used in constructing cut-off walls to inhibit groundwater movement in contaminated sites. This study prepares SCB backfill with fixed fluidity. We conducted a series of experiments to investigate the engineering characteristics and microscopic mechanism of the backfill. The results indicate that the water content in the slurry was more sensitive to the bentonite content. The unconfined compression strength (UCS) value increased with an increase in the cement content, and the change with an increase in bentonite content was not noticeable. The permeability coefficient decreased distinctly with an increase in the cement and bentonite contents. The porosity of the SCB backfill increased with increasing bentonite content and decreased with increasing cement content. The UCS of SCB backfill was linearly and negatively correlated with the porosity; the permeability coefficient was not significantly related to the porosity. The percentage of micro- and small-pore throats in the backfill increased with increasing bentonite and cement contents. As cement and bentonite content increased by 6% in the backfill, the proportion of micro- and small-pore throats increased by 0.7% and 1.2%, respectively. The percentage of micro- and small-pore throats is deduced to be more suitable as a characterization parameter for the permeability of the SCB backfill. The overall results of this study show that the reasonably proportioned SCB backfill has potential as an eco-friendly and cost-effective material. Based on the requirements of strength and permeability coefficient (UCS > 100 kPa, 28 days permeability coefficient <1 × 10−7 cm/s), we suggested using a backfill with 12% bentonite and 9% cement as the cut-off wall mix ratio.

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