Experimental and Numerical Evaluation of the Effect of Nano Calcium Carbonate on Geotechnical Properties of Clayey Sand Soil

2021 ◽  
Author(s):  
Mostafa Mohammadi ◽  
Ali M. Rajabi ◽  
Mahdi Khodaparast
Keyword(s):  
Calcium Carbonate ◽  
Numerical Evaluation ◽  
Geotechnical Properties ◽  
Clayey Sand ◽  
Sand Soil

scholarly journals Physical and geotechnical properties of a silty sand soil treated with calcium carbonate fixing bacteria

2020 ◽  
Vol 195 ◽  
pp. 05002
Author(s):  
E. Garzón ◽  
L. Morales ◽  
J. Reca ◽  
E. Romero ◽  
P.J. Sánchez-Soto
Keyword(s):  
Calcium Carbonate ◽  
Friction Angle ◽  
Geotechnical Properties ◽  
Silty Sand ◽  
Natural Soil ◽  
Dry Density ◽  
Sand Soil ◽  
Precipitated Calcium Carbonate ◽  
Mineralogical Characterization ◽  
Treated Soil

The objective of the present study is to develop a biotechnological tool for a new application of silty sand soil as stabilized materials in linear works replacing chemical stabilizer (e.g. cement and lime) by natural cement, formed by precipitated calcium carbonate generated by microorganisms of the Sporosarcina family. For this purpose, it is conducted a chemical and mineralogical characterization and an examination of physical and geotechnical properties, being very important from the engineering standpoint. The results of different tests are presented here. The data show that the effects of bacteria are reducing the soil specific surface and increasing its plasticity. The reason for this result could be the addition of a plastic component to the natural soil, or the result of the more aggregated structure promoted during the treatment. The pore size distribution of the soil changes in an approximate range 3 - 30 µm, where the pore mode tends to disappear. The change in the pore density function is reflected in the mechanical behaviour of the treated soil, which presents typical features of a less dense soil with respect to the natural untreated one. The friction angle of the treated soil is slightly higher, and its compressibility is consistently lower than that of the natural soil. As the bacteria do not seem to produce any cementation effect on the soil skeleton, collapse upon wetting does not seem to be significantly affected by the treatment. On the contrary, comparison of collapse data shows that occurrence and amount of collapse are ruled by the as-compacted dry density. The tests performed seem to suggest that the microbiological technique may be effective to improve the mechanical characteristics of the compacted soil. For that, it is necessary to provide more energy in compacting the treated soil that it will be stabilized, so as to achieve a high initial dry density. From this viewpoint, it seems that higher compaction effort is even more effective than increasing the amount of bacteria introduced to stabilize the soil.

Geotechnical Properties of β-Glucan-Treated Clayey Sand

2020 ◽  
pp. 63-73
Author(s):  
M. Vishweshwaran ◽  
Evangelin Ramani Sujatha ◽  
Nadendla Harshith ◽  
Cheni Umesh
Keyword(s):  
Geotechnical Properties ◽  
Clayey Sand

Field Test of Nonfuel Hydrocarbon Bioventing in Clayey-Sand Soil

1997 ◽  
Vol 1 (2) ◽  
pp. 123-133 ◽  
Author(s):  
Gregory D. Sayles ◽  
Andrea Leeson ◽  
Melinda A. Trizinsky ◽  
Philip Rotstein
Keyword(s):  
Field Test ◽  
Clayey Sand ◽  
Sand Soil

scholarly journals Laboratory investigation of geotextile position on CBR of clayey sand soil under freeze-thaw cycle

2019 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Behnam Shams ◽  
Alireza Ardakani ◽  
Mahya Roustaei
Keyword(s):  
Laboratory Investigation ◽  
Clayey Sand ◽  
Sand Soil ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Freeze Thaw Cycle

scholarly journals Shear Strength Characteristics of Cemented Clayey Sand Soil

2021 ◽  
Vol 0 (0) ◽  
pp. 0-0
Author(s):  
Mona Bayoumy ◽  
Mostafa Alsawwaf ◽  
ahmed nasr
Keyword(s):  
Shear Strength ◽  
Strength Characteristics ◽  
Clayey Sand ◽  
Sand Soil

scholarly journals Analysis of the Physical-Mechanical Behavior of Clayey Sand Soil Improved with Coir Fiber

2019 ◽  
Vol 42 (1) ◽  
pp. 31-42
Author(s):  
Lucas Chagas Paes de Menezes ◽  
Danielle Barbosa de Sousa ◽  
Stela Fucale Sukar ◽  
Sílvio Romero de Melo Ferreira
Keyword(s):  
Mechanical Behavior ◽  
Coir Fiber ◽  
Clayey Sand ◽  
Sand Soil

A TEM study of the microstructure of avian eggshells

1992 ◽  
Vol 50 (2) ◽  
pp. 1102-1103
Author(s):  
S. Q. Xiao ◽  
S. Baden ◽  
A. H. Heuer
Keyword(s):  
Electron Microscope ◽  
Calcium Carbonate ◽  
Nucleation And Growth ◽  
Growth Mechanisms ◽  
Shell Surface ◽  
Thin Sections ◽  
Polycrystalline Metals ◽  
Transmission Electron ◽  
Nucleation And Growth Mechanisms

The avian eggshell is one of the most rapidly mineralizing biological systems known. In situ, 5g of calcium carbonate are crystallized in less than 20 hrs to fabricate the shell. Although there have been much work about the formation of eggshells, controversy about the nucleation and growth mechanisms of the calcite crystals, and their texture in the eggshell, still remain unclear. In this report the microstructure and microchemistry of avian eggshells have been analyzed using transmission electron microscope (TEM) and energy dispersive spectroscopy (EDS).Fresh white and dry brown eggshells were broken and fixed in Karnosky's fixative (kaltitanden) for 2 hrs, then rinsed in distilled H2O. Small speckles of the eggshells were embedded in Spurr medium and thin sections were made ultramicrotome.The crystalline part of eggshells are composed of many small plate-like calcite grains, whose plate normals are approximately parallel to the shell surface. The sizes of the grains are about 0.3×0.3×1 μm3 (Fig.l). These grains are not as closely packed as man-made polycrystalline metals and ceramics, and small gaps between adjacent grains are visible indicating the absence of conventional grain boundaries.

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