Evaluation of Soil-Cement-Bentonite Wall Performance - Effects of Backfill Shrinkage

Čermák, Jan; Evans, Jeffrey; Tamaro, George J.

doi:10.1061/9780784412350.0036

Cited by 14 publications

(8 citation statements)

References 3 publications

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“…The drying process is irreversible, such that immersion of dried samples in water does not return them to their original state [71]. Cermak et al (2012) explained that shrinkage has a great impact on stress states in barrier materials [72]. In the vertical and longitudinal directions, the continuous and homogeneous nature of the barrier and friction on the barrier sides offer restraint, and, therefore, the shrinkage can lead to a decrease in the compressive stress and possible development of tensile stress.…”

Section: Damage Due To Aggressive Environmentsmentioning

confidence: 99%

Vertical Barriers for Land Contamination Containment: A Review

Cao

Wang

et al. 2021

IJERPH

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Soil pollution is one of the major threats to the environment and jeopardizes the provision of key soil ecosystem services. Vertical barriers, including slurry trench walls and walls constructed with soil mix technology, have been employed for decades to control groundwater flow and subsurface contaminant transport. This paper comprehensively reviewed and assessed the typical materials and mechanical and permeability properties of soil–bentonite, cement–bentonite and soil mix barriers, with the values of mix design and engineering properties summarized and compared. In addition, the damage and durability of barrier materials under mechanical, chemical, and environmental stresses were discussed. A number of landmark remediation projects were documented to demonstrate the effectiveness of the use of barrier systems. Recent research about crack-resistant and self-healing barrier materials incorporating polymers and minerals at Cambridge University and performance monitoring techniques were analyzed. Future work should focus on two main areas: the use of geophysical methods for non-destructive monitoring and the optimization of resilient barrier materials.

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Section: Damage Due To Aggressive Environmentsmentioning

confidence: 99%

Vertical Barriers for Land Contamination Containment: A Review

Cao

Wang

et al. 2021

IJERPH

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“…In spite of the well-established design and construction approaches of slag-cementbentonite slurry walls, the materials deteriorate inevitably in contaminated land [3,[9][10][11]. The damage of slurry walls can result in undermined strength and durability, affecting their sustainability and even leading to undetected physical damage of the wall.…”

Section: Introductionmentioning

confidence: 99%

SEBS-Polymer-Modified Slag–Cement–Bentonite for Resilient Slurry Walls

2022

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In spite of the well-established design and construction approaches of slag–cement–bentonite slurry walls, the materials deteriorate inevitably in contaminated land. The development of effective materials which are sustainable, resilient and self-healing over the lifetime of slurry walls becomes essential. This study, for the first time, adopts a styrene–ethylene/butylene–styrene (SEBS) polymer to modify slag–cement–bentonite materials to enhance mechanical and self-healing performance. The results show that the increase in SEBS dosage results in significantly increased strain at failure, indicating the enhanced ductility thanks to the modification by the deformable polymer. The increased ductility is beneficial as the slurry wall could deform to a greater extent without cracks. After the permeation of liquid paraffin, the SEBS exposed on the crack surface swells and seals the crack, with the post-healing permeability only slightly higher than the undamaged values, which exhibits good self-healing performance. Scanning electron microscopy and micro-computed tomography analyses innovatively reveal the good bonding and homogeneous distribution of SEBS in slag–cement–bentonite. SEBS acts as a binder to protect the slag–cement–bentonite sample from disintegration, and the swollen SEBS particles effectively seal and heal the cracks. These results demonstrate that the SEBS-modified slag–cement–bentonite could provide slurry walls with resilient mechanical properties and enhanced self-healing performance.

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“…The portion of the cut-off wall near the groundwater table was particularly susceptible to wet-dry cycles due to seasonal fluctuations of the groundwater (Joshi et al, 2010). During the construction of a cut-off wall, evaluated by Cermak et al (2012), vertical cracks were D r a f t 4 observed in the borehole sidewalls at the locations of field permeability tests. It was observed that all cracks were essentially vertical and the widths ranged from approximately 0.5 mm to 1.5 mm.…”

Section: Introductionmentioning

confidence: 99%

Crack-resistant cement–bentonite cut-off wall materials incorporating superabsorbent polymers

2021

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Preserving the integrity of cement-bentonite cut-off walls, particularly in aggressive environments, is critical to their serviceability in polluted sites. The hardened cement-bentonite material in cut-off walls is highly susceptible to desiccation and wet-dry cycles, commonly leading to cracking. The objective of the work presented in this paper was to develop crack-resistant cement-bentonite cut-off wall materials subject to wet-dry cycles. Superabsorbent polymers (SAPs), which are cross-linked polymers that can absorb and retain a large amount of water and swell as a result, were employed for this purpose. It is found that the added SAPs increased the compressive strength by decreasing the water to cement ratio, and that the strain at failure also increased due to energy dissipative and reinforcement effects. In addition, crack resistance was greatly improved under the imposed wet-dry cycles as the matrix suction was reduced as a result of the reduction of the contact between the free pore water and cement-bentonite particles and the increase of the pore size in the matrix. The morphology and microstructure of the interconnected foam network formed by the SAP films in the matrix were identified with SEM-EDX and micro-CT scan analyses. The results demonstrated the significant potential for SAPs in the development of crack-resistant cement-bentonite cut-off wall materials.

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Evaluation of Soil-Cement-Bentonite Wall Performance - Effects of Backfill Shrinkage

Cited by 14 publications

References 3 publications

Vertical Barriers for Land Contamination Containment: A Review

Vertical Barriers for Land Contamination Containment: A Review

SEBS-Polymer-Modified Slag–Cement–Bentonite for Resilient Slurry Walls

Crack-resistant cement–bentonite cut-off wall materials incorporating superabsorbent polymers

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