scholarly journals Desiccation Cracking Behavior of Polyurethane and Polyacrylamide Admixed Clayey Soils

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2398
Author(s):  
Changqing Qi ◽  
Yuxia Bai ◽  
Jin Liu ◽  
Fan Bu ◽  
Debi Prasanna Kanungo ◽  
...  
Keyword(s):  
Hydraulic Properties ◽  
Polymer Concentration ◽  
Soil Reinforcement ◽  
Clayey Soils ◽  
Cracking Behavior ◽  
Treated Soil ◽  
Desiccation Cracking ◽  
Evaporation Stage ◽  
Scanning Electron ◽  
Sem Analyses

There has been a growing interest in polymer applied for soil reinforcement in recent years. However, there little attention has been paid to the effects of polymer on soil cracking behavior, and cracks significantly change soil strength and hydraulic properties and alter reinforcement effectiveness. This study investigated the desiccation cracking behavior of polyurethane (PU) and polyacrylamide (PAM) admixed clayey soils with different polymer concentrations by performing desiccation cracking tests. Scanning electron microscope (SEM) observation was also carried out to obtain the internal structure of these soils. The results show that PU and PAM addition both prolonged the initial evaporation stage, accelerated later evaporation processes, and the effects were related to polymer concentration. Final cracks morphology analyses show that PAM addition slightly reduced the cracking and crushing degree and kept the soil relatively intact, while PU addition slightly enhanced the cracking and crushing degree of soil. In addition, PU and PAM addition both increased the width and length of cracks. The scanning electron microscopy (SEM) analyses show that the effects of polymer on soil evaporation and cracking could be concluded as: (1) storing water in voids, (2) influencing water immigration channel, (3) providing space for soil shrinkage, and (4) enhancing the connection between aggregates, which did not fully come into play because of the existence of hydrogel form. These achievements provide a certain basis for the research of desiccation cracking behavior of polymer treated soil and make significant sense for the safe and effective running of related projects.

scholarly journals Experiment evidence on the temperature dependence of desiccation cracking behavior of clayey soils

2010 ◽  
Vol 114 (3-4) ◽  
pp. 261-266 ◽  
Author(s):  
Chao-Sheng Tang ◽  
Yu-Jun Cui ◽  
Anh-Minh Tang ◽  
Bin Shi
Keyword(s):  
Temperature Dependence ◽  
Clayey Soils ◽  
Cracking Behavior ◽  
Desiccation Cracking

Desiccation Cracking Behavior of Clayey Soils Treated with Biocement and Bottom Ash Admixture during Wetting–Drying Cycles

2020 ◽  
Vol 2674 (8) ◽  
pp. 441-454
Author(s):  
Mark Vail ◽  
Cheng Zhu ◽  
Chao-Sheng Tang ◽  
Nate Maute ◽  
Melissa Tababa Montalbo-Lomboy
Keyword(s):  
Soil Stabilization ◽  
Particle Surface ◽  
Bottom Ash ◽  
Clayey Soils ◽  
Calcite Precipitation ◽  
Cracking Behavior ◽  
Earth Structures ◽  
Desiccation Cracking ◽  
Long Term Performance ◽  
Term Performance

Desiccation cracking considerably impairs the hydraulic and mechanical properties of clayey soils that are critical to the long-term performance of infrastructure foundations and earth structures. Typical crack remediation methods are associated with high labor and maintenance costs or the use of environmentally unfriendly chemicals. Recycling waste materials and developing biomediated techniques have emerged as green, sustainable soil stabilization solutions. The objective of this study was to investigate the feasibility of soil crack remediation through use of bottom ash admixtures and microbial-induced calcite precipitation (MICP). We carried out cyclic wetting–drying tests to characterize the effects of bottom ash and MICP on the desiccation cracking behaviors of bentonite soils. Two groups of soil samples that contained different percentages of bottom ash (0%, 20%, 40% by weight) were prepared for cyclic water and MICP treatments, respectively. The desiccation cracking patterns captured by a high-resolution camera were quantified using image processing. We also employed scanning electron microscopy for microstructural characterizations. Experimental results revealed that cyclic water treatment resulted in more cracking, whereas cyclic MICP treatment improved soil strength owing to the precipitation of calcite crystals on the soil particle surface and inside the interparticle pores. Adding bottom ash to bentonite reduced the plasticity of the mixture, promoted the flocculation of clay particles by cation exchange, and also provided soluble calcium to enhance calcite precipitation. This study demonstrates the potential of bottom ash and MICP for crack remediation and brings new insights into the design and assessment of sustainable infrastructures under climate changes.

scholarly journals A Review of Cracking Behavior and Mechanism in Clayey Soils Related to Desiccation

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xin Wei ◽  
Chongyang Gao ◽  
Ke Liu
Keyword(s):  
Fracture Mechanics ◽  
Hydraulic Properties ◽  
Soil Mechanics ◽  
Clayey Soils ◽  
Cracking Behavior ◽  
Field Investigations ◽  
Experimental Approaches ◽  
In Situ Observations ◽  
Numerical Approaches

Cracks in clayey soils are common during desiccation. The presence of cracks significantly alters the mechanical and hydraulic properties of soils. The objective of this article is to summarize the works on cracking behavior and mechanism in clayey soils related to desiccation. Historical field investigations, laboratory experimentations, identified mechanisms, and numerical approaches for modeling the process of cracking during desiccation are discussed. The experimental approaches for interpreting the mechanisms of cracking are systematically summarized and comprehensively reviewed based on the in situ observations and laboratory experimentations from the literature. The soil mechanics-based approaches resumed in this article according to the fracture mechanics theory and numerical results highlight the cracking development mechanism. Concerning the plasticity characteristics of clayey soils, researches on soil fracture mechanics should be paid more attention. More in situ experimentations and numerical researches are suggested for future researches to better understand the cracking behavior and mechanism in clayey soils related to desiccation.

scholarly journals Desiccation Cracking Behavior of MICP-Treated Bentonite

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 385 ◽  
Author(s):  
Vail ◽  
Zhu ◽  
Tang ◽  
Anderson ◽  
Moroski ◽  
...  
Keyword(s):  
Clayey Soils ◽  
Fluid Type ◽  
Calcite Precipitation ◽  
Crack Evolution ◽  
Cracking Behavior ◽  
Soil Desiccation ◽  
Cracking Potential ◽  
Desiccation Cracking ◽  
Mixed Bacteria ◽  
Calcium Bentonite

This study aims to characterize the effect of microbial-induced calcite precipitation (MICP) on the desiccation cracking behaviors of compacted calcium bentonite soils. We prepare six groups of samples by mixing bentonites with deionized water, pure bacteria solution, pure cementation solution, and mixed bacteria and cementation solutions at three different percentages. We use an image processing tool to characterize the soil desiccation cracking patterns. Experimental results reveal the influences of fluid type and mixture percentage on the crack evolution and volumetric deformation of bentonite soils. MICP reactions effectively delay the crack initiation and remediate desiccation cracking, as reflected by the decreased geometrical descriptors of the crack pattern such as surface crack ratio. The mixture containing 50% bacteria and 50% cementation solutions maximizes the MICP treatment and works most effectively in lowering the soil cracking potential. This study provides new insights into the desiccation cracking of expansive clayey soils and shows the potential of MICP applications in the crack remediation.

Investigation on desiccation cracking behavior of clayey soils with a perspective of fracture mechanics: a review

2021 ◽  
Author(s):  
Jin-Jian Xu ◽  
Chao-Sheng Tang ◽  
Qing Cheng ◽  
Qi-liang Xu ◽  
Hilary I. Inyang ◽  
...  
Keyword(s):  
Fracture Mechanics ◽  
Clayey Soils ◽  
Cracking Behavior ◽  
Desiccation Cracking

Tensile behavior of clayey soils during desiccation cracking process

2020 ◽  
Vol 279 ◽  
pp. 105909
Author(s):  
Qing Cheng ◽  
Chao-Sheng Tang ◽  
Zhi-guo Chen ◽  
Mohamed Ramy El-Maarry ◽  
Hao Zeng ◽  
...  
Keyword(s):  
Tensile Behavior ◽  
Clayey Soils ◽  
Desiccation Cracking ◽  
Cracking Process

scholarly journals Eu luminescence from BaTiO3/SiO2 multilayer xerogel structures

2020 ◽  
Vol 10 (03) ◽  
pp. 2050005
Author(s):  
N. Gaponenko ◽  
D. Parafinyuk ◽  
P. Kholov ◽  
T. Raichenok ◽  
S. Prislopski
Keyword(s):  
Luminescence Intensity ◽  
Multilayer Structure ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Fused Silica ◽  
Room Temperature Luminescence ◽  
Scanning Electron ◽  
The Eu ◽  
Sem Analyses

Sol–gel technology was applied to fabricate Eu-doped BaTiO3/SiO2 multilayer structures by spinning on silicon and fused silica substrates. Eu photoluminescence (PL) was investigated depending on the annealing temperature of these structures. The samples demonstrate the room temperature luminescence corresponding to 5[Formula: see text]FJ ([Formula: see text], 2, 3, 4) transitions of trivalent europium with the most intensive band at 615 nm. For the structure on fused silica with Eu in the BaTiO3 cavity, increase of the annealing temperature from [Formula: see text]C to [Formula: see text]C results in modification of the luminescence indicatrix and lowering of the luminescence intensity in the direction along the surface normal. For BaTiO3/SiO2 multilayer structure generated on silicon, scanning electron microscopy (SEM) analyses reveal disordering after annealing at [Formula: see text]C. This heat treatment provides also an increase of the Eu luminescence intensity.

Tribological Study of Xanthate-Containing Acetic Ester as Additives in Hydrogenated Oil

2012 ◽  
Vol 236-237 ◽  
pp. 123-127 ◽  
Author(s):  
Chao Long Li ◽  
Li Ping Xiong ◽  
Hong Liu ◽  
Li Ting Xiong ◽  
Wei Wang
Keyword(s):  
Photoelectron Spectroscopy ◽  
Protective Film ◽  
Extreme Pressure ◽  
Action Mechanism ◽  
Prepared Compound ◽  
X Ray ◽  
Hydrogenated Oil ◽  
Worn Surface ◽  
Scanning Electron ◽  
Sem Analyses

A novel ester derivative, dodecyl xanthate acetic dodecyl xanthate ester(DXAD) was synthesized and it’s tribological behaviors as additives in hydrogenated oil, were evaluated using a four-ball tester. Results show that the compound possesses good antiwear performance, extreme pressure capacity, and good friction-reducing property. The action mechanism was estimated through analysis of the worn surface with X-ray photoelectron spectroscopy (XPS) and Scanning Electron Microscope (SEM). The results of XPS and SEM analyses illustrate that the prepared compound as an additive in hydrogenated oil forms a protective film containing ferric sulfide and ferric sulfate compounds on the rubbed surface.

Microwave irradiation used for all steps of pre-pillaring Al-montmorillonite

Clay Minerals ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 267-278 ◽  
Author(s):  
S. Yapar ◽  
R. M. Torres Sánchez ◽  
M. Emreol ◽  
P. Weidler ◽  
K. Emmerich
Keyword(s):  
Microwave Irradiation ◽  
Physicochemical Properties ◽  
Structural Changes ◽  
Thermal Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ageing Processes ◽  
Pillared Montmorillonites ◽  
Scanning Electron ◽  
Sem Analyses

AbstractIn this study, a new procedure for the synthesis of pillared clays is proposed. Ageing processes and intercalation reactions were carried out using microwave irradiation in order to decrease the consumption of three industrially-important parameters; time, water consumption and energy. The effects of microwave irradiation, the amount of Al and the Al3+/clay ratio on the physicochemical properties of Al-pillared montmorillonites were investigated. The structural changes, depending on the intercalation and microwave irradiation, were characterized using X-ray diffraction (XRD), Fourier-transform infrared (FTIR) and scanning electron microscopy (SEM) analyses and by measuring the specific surface area and pore-size distribution. Additionally, simultaneous thermal analyses (STA) and zeta potential measurements were carried out to determine physicochemical properties. According to the XRD measurements, the d001 value of microwave-irradiated samples is not affected by the amount of Al and the Al3+/clay ratio; microwave irradiation causes a 0.20 nm contraction in the d001 value in comparison to that of a conventionally pillared sample. The results of FTIR analyses reveal that the intensity of peaks assigned to Keggin-OH and Keggin-H2O stretches is diminished in the case of microwave-irradiated samples. The STA analyses indicate that the amount of water released during dehydroxylation is decreased in the case of microwave-irradiated samples. By considering the contraction in d001 values and the decreases in Keggin-stretching bands and also in the amount of dehydroxylation water, it was concluded that microwave irradiation has a calcination effect.

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