scholarly journals The Influence of Mixing Orders on the Microstructure of Artificially Prepared Sand-Clay Mixtures

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Kexin Yin ◽  
Anne-Laure Fauchille ◽  
Eugenia Di Filippo ◽  
Khaoula Othmani ◽  
Samuel Branchu ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Soil Stabilization ◽  
Underground Mining ◽  
Road Construction ◽  
Soil Liquefaction ◽  
Silica Sand ◽  
Clay Particles ◽  
X Ray ◽  
Homogeneous Matrix ◽  
Water Contents

The mixing order of silica sand, clay (kaolinite), and water controls the microstructure of resulting artificial soil samples. Most homogeneous microstructures can be achieved by applying the mixing order “sand-water-clay.” The following methods were used to validate this statement: (1) optical observation, (2) X-ray tomography, (3) scanning electron microscopy, and (4) Mercury intrusion porosimetry. For all samples, clays are mainly organized in a homogeneous matrix but are also dispersed heterogeneously in micrometer-sized layers surrounding sand particles, particularly where sand grains show a greater roughness. At water contents ≥1.5 w L , the microstructures are visually similar from the mm to μm scale whatever mixing order is used. However, for water contents lower than 1.5 w L , the mixing order controls the distribution of the clay particles. This paper proposes a motivated choice of a preparation protocol of artificial clayey materials to be used in laboratory experiments. It might contribute to better understanding and modeling grain movements and arrangements in artificial muds, used for instance in underground mining, foundation settlement, hydraulic containment, road construction, soil stabilization, and in natural soils in the occurrence of soil liquefaction, industrial brick manufacturing, and in studying shear processes in tectonic fault zones.

scholarly journals Effects of Initial Water Content on Microstructure and Mechanical Properties of Lean Clay Soil Stabilized by Compound Calcium-Based Stabilizer

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1933 ◽  
Author(s):  
Chenglong Yin ◽  
Wei Zhang ◽  
Xunli Jiang ◽  
Zhiyi Huang
Keyword(s):  
Water Content ◽  
Soil Stabilization ◽  
Clay Soil ◽  
Soil Aggregates ◽  
Optical Microscope ◽  
Initial Water Content ◽  
Reaction Products ◽  
Unconfined Compression Test ◽  
Initial Water ◽  
X Ray

Initial water content significantly affects the efficiency of soil stabilization. In this study, the effects of initial water content on the compressibility, strength, microstructure, and composition of a lean clay soil stabilized by compound calcium-based stabilizer were investigated by static compaction test, unconfined compression test, optical microscope observations, environment scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results indicate that as the initial water content increases in the range studied, both the compaction energy and the maximum compaction force decrease linearly and there are less soil aggregates or agglomerations, and a smaller proportion of large pores in the compacted mixture structure. In addition, for specimens cured with or without external water supply and under different compaction degrees, the variation law of the unconfined compressive strength with initial water content is different and the highest strength value is obtained at various initial water contents. With the increase of initial water content, the percentage of the oxygen element tends to increase in the reaction products of the calcium-based stabilizer, whereas the primary mineral composition of the soil-stabilizer mixture did not change notably.

scholarly journals Ultrasonic, Molecular and Mechanical Testing Diagnostics in Natural Fibre Reinforced, Polymer-Stabilized Earth Blocks

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
C. Galán-Marín ◽  
C. Rivera-Gómez ◽  
F. Bradley
Keyword(s):  
Soil Stabilization ◽  
Ultrasonic Pulse Velocity ◽  
Mechanical Tests ◽  
Pulse Velocity ◽  
Mechanical Resistance ◽  
Chemical Compositions ◽  
Natural Polymer ◽  
Natural Polymers ◽  
X Ray ◽  
Earth Blocks

The aim of this research study was to evaluate the influence of utilising natural polymers as a form of soil stabilization, in order to assess their potential for use in building applications. Mixtures were stabilized with a natural polymer (alginate) and reinforced with wool fibres in order to improve the overall compressive and flexural strength of a series of composite materials. Ultrasonic pulse velocity (UPV) and mechanical strength testing techniques were then used to measure the porous properties of the manufactured natural polymer-soil composites, which were formed into earth blocks. Mechanical tests were carried out for three different clays which showed that the polymer increased the mechanical resistance of the samples to varying degrees, depending on the plasticity index of each soil. Variation in soil grain size distributions and Atterberg limits were assessed and chemical compositions were studied and compared. X-ray diffraction (XRD), X-ray fluorescence spectroscopy (XRF), and energy dispersive X-ray fluorescence (EDXRF) techniques were all used in conjunction with qualitative identification of the aggregates. Ultrasonic wave propagation was found to be a useful technique for assisting in the determination of soil shrinkage characteristics and fibre-soil adherence capacity and UPV results correlated well with the measured mechanical properties.

scholarly journals The Effect of Silica Sand Proportion in Laser Scabbling Process on Cement Mortar

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1914
Author(s):  
Tam-Van Huynh ◽  
Youngjin Seo ◽  
Dongkyoung Lee
Keyword(s):  
Cement Mortar ◽  
Silica Sand ◽  
Construction Sites ◽  
Power Laser ◽  
Concrete Repair ◽  
X Ray ◽  
Micro Cracks ◽  
Wide Range ◽  
Cement Based Materials ◽  
Composition Changes

Cement mortar composite has a wide range of applications on construction sites, including masonry, plastering and concrete repair. In construction sites, scabbling process is a method to remove from a few millimeters to several centimeters of defect concrete surfaces. As a result, it is essential to investigate the scabbling characteristics for cement mortar with different silica sand proportion in laser scabbling process. In this study, 5 types of cement mortar with different silica sand proportions in mixing were fabricated and scabbled by using a high-density power laser beam. The effects of silica sand proportion in color changing and penetration depth of the samples after laser scabbling process were studied. Furthermore, the generation of micro-cracks and pores were observed by using scanning electron microscopy (SEM). In addition, chemical composition changes between processed zone and non-processed zone were also evaluated by Energy Dispersive X-ray (EDX) analysis. The results of this study are expected to provide valuable knowledge in understanding of the laser scabbling process for cement-based materials.

scholarly journals Addition Effect of Petrasoil Additive Material on CBR Value of Soil in Swamp Areas

2019 ◽  
Vol 3 (2) ◽  
pp. 67-70 ◽  
Author(s):  
Andi Herius ◽  
Indrayani Indrayani Indrayani ◽  
Arfan Hasan ◽  
Ahmad Mirza
Keyword(s):  
Water Content ◽  
Soil Water Content ◽  
Construction Projects ◽  
Soil Stabilization ◽  
Road Construction ◽  
Dry Weight ◽  
Soil Conditions ◽  
Index Properties ◽  
Soil Density ◽  
Road Project

Some road construction projects use petrasoil additive to increase soil stabilization, one of then is the Improvement of Tabarfane-Hokmar (Chemical Petrasoil) Road Project in Aru Selatan Timur District, Aru Islands. To obtain the influence of petrasoil aditive material as soil stabilization in swamp areas, a research is needed. petrasoil additives that powder shape are dissolved in water with 3 variations, namely 500 liters, 750 liters, and 1000 liters of water. Tests which carried out include compaction testing, index properties, and CBR. The results showed that the addition of petrasoil mixture with water without being combined with other added ingredients could lead to increasingly unstable soil conditions where the soil water content increased and the dry weight of the soil diminished, meaning that soil density decreases, and the CBR value of soil decreases.

scholarly journals Gold Mine Tailings: A Potential Source of Silica Sand for Glass Making

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 448 ◽  
Author(s):  
Uchenna Okereafor ◽  
Mamookho Makhatha ◽  
Lukhanyo Mekuto ◽  
Vuyo Mavumengwana
Keyword(s):  
Mine Tailings ◽  
Potentially Toxic Elements ◽  
Silica Sand ◽  
Mine Wastes ◽  
Gold Mine ◽  
X Ray Diffraction ◽  
X Ray ◽  
Potential Source ◽  
Gold Mine Tailings ◽  
Cadmium Zinc

Mining of minerals such as gold, copper, and platinum has been one of several activities sustaining the economy of South Africa. However, the mining sector has contributed significantly to environmental contamination through the improper disposal of mine tailings which covers vast areas of land. Therefore, this study utilised a vitrification process to manufacture glass from gold mine tailings. X-ray fluorescence was used to determine the chemical composition of the tailings while X-ray diffraction was adopted for the mineralogy. The tailings were of granitic composition enriched in potentially toxic elements such as copper, cadmium, zinc, lead, arsenic, and chromium. A representative sample of gold mine wastes of sandy grain size was used in making the glass. Based on composition, the glass was formulated by adding an average 10.0 mass% of CaCO3 and 5.0 mass% of Na2CO3 to 35.0 mass% of SiO2, which resulted in the production of a green-coloured glass.

scholarly journals The use of sodium polytungstate as an X-ray contrast agent to reduce the beam hardening artifact in hydrological laboratory experiments

2013 ◽  
Vol 61 (4) ◽  
pp. 347-352 ◽  
Author(s):  
Yoshito Nakashima
Keyword(s):  
Contrast Agent ◽  
Laboratory Experiments ◽  
Source Spectrum ◽  
Ct Scanner ◽  
Beam Hardening ◽  
Two Phase ◽  
X Ray ◽  
X Ray Computed ◽  
Element Bearing ◽  
Sodium Polytungstate

Abstract Iodine is conventionally used as a contrast agent in hydrological laboratory experiments using polychromatic X-ray computed tomography (CT) to monitor two-phase Darcy flow in porous geological media. Undesirable beam hardening artifacts, however, render the quantitative analysis of the obtained CT images difficult. CT imaging of porous sand/bead packs saturated with iodine and tungsten-bearing aqueous solutions, respectively, was performed using a medical CT scanner. We found that sodium polytungstate (Na6H2W12O40) significantly reduced the beam hardening compared with potassium iodide (KI). This result is attributable to the location of the K absorption edge of tungsten, which is nearer to the peak of the polychromatic X-ray source spectrum than that of iodine. As sodium polytungstate is chemically stable and less toxic than other heavy element bearing compounds, we recommend it as a promising contrast agent for hydrological CT experiments.

Lyotropic Phase Behaviour and Structural Parameters of Monosaccharide and Disaccharide Guerbet Branched-Chain β-D-Glycosides

2014 ◽  
Vol 895 ◽  
pp. 111-115 ◽  
Author(s):  
Hairul A.A. Hamid ◽  
Rauzah Hashim ◽  
John M. Seddon ◽  
Nicholas J. Brooks
Keyword(s):  
Self Assembly ◽  
Room Temperature ◽  
Structural Parameters ◽  
Phase Behaviour ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Branched Chain ◽  
Optical Polarizing Microscopy ◽  
Water Contents

The phase behaviour and self-assembly structural parameters of a pair of monosaccharide and disaccharide Guerbet branched-chain β-D-glycosides, namely 2-octyldodecyl β-D-glucoside (β-Glc-C12C8) and 2-octyldodecyl β-D-maltoside (β-Mal-C12C8), have been studied by means of optical polarizing microscopy (OPM) and small-angle X-ray diffraction at room temperature (25°C). These compounds are sugar-based glycolipid surfactants having a total chain length of C20, and differ based on the increasing number of hydroxyl groups of the sugar headgroup (glucose and maltose). The repeat spacings obtained by X-ray diffraction as a function of water content have been used to determine the limiting hydration for the two glycosides. At room temperature, β-Glc-C12C8 and β-Mal-C12C8 have limiting hydrations of 22 wt% and 25 wt%, corresponding to 8 10 and 10 12 water molecules per glycoside, respectively. At all water contents between 5 and 29 wt % water, these compounds adopt inverse hexagonal (HII) or fluid lamellar (Lα) phases. The structural parameters of these phases have been determined from the diffraction data, from the X-ray repeat spacings, densities and concentration of the glycosides.

scholarly journals Dielectronic Satellite Spectra in the Soft X-Ray Region

1972 ◽  
Vol 14 ◽  
pp. 655-664 ◽  
Author(s):  
A.H. Gabriel
Keyword(s):  
Steady State ◽  
Solar Flare ◽  
Resonance Line ◽  
Laboratory Experiments ◽  
Transient State ◽  
Dielectronic Recombination ◽  
The Sun ◽  
X Ray ◽  
Long Wavelength ◽  
Dielectronic Satellite

AbstractSatellite lines, situated on the long wavelength side of the helium-like ion resonance line, can be observed in highly-ionized ions both in laboratory sources and from the Sun. Although seen for more than 30 years, these lines have only recently been classified in detail as inner-shell transitions in lithium-like ions. Laboratory experiments have shown that under steady-state conditions these satellites are produced by dielectronic recombination, although in transient ionizing plasmas direct inner-shell excitation can be important. Detailed calculations have been carried out for high Z ions up to copper, and the results can be compared with solar flare spectra in iron. Such comparisons allow both the electron temperature and the transient state of the plasma to be determined. Laboratory spectra from such high-Z ions are different in appearance, and may be dominated by processes resulting from the transient ionizing state of the plasma.

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