scholarly journals Geotechnical aspects of Alluvial soils at different depths under sodium chloride action, Najran region, Saudi Arabia: Field supported by laboratory tests

2021 ◽  
Author(s):  
Ahmed Abd El Aal ◽  
Gamil Abdullah
Keyword(s):  
Saudi Arabia ◽  
Shear Strength ◽  
Sodium Chloride ◽  
Base Material ◽  
Dry Density ◽  
Chloride Salt ◽  
Arid Soils ◽  
X Ray ◽  
Geotechnical Characteristics ◽  
Semi Arid

Abstract The present work is to investigated the effect of sodium chloride (NaCl) on the behavior of semi-arid soils in the Najran region of Saudi Arabia. An experiment work was carried out to investigate how the addition of (NaCl) "salt" to semi-arid soils collected from Najran region affects the Atterberg limits, compaction characteristics, California Bearing Ratio (CBR) and shear strength. All tests were performed on soils samples collected from different areas in Najran region at various depths of 1.5, 3, and 4.5 m along soil profiles. Soils samples were tested alone and then compared with the same soils samples mixed with sodium chloride (salt) at different percentages of 5, 10, and 20% respectively. Using advanced techniques, such as the scanning electron microscope (SEM), energy dispersive x-ray analysis (EDX) and X-ray diffraction analysis (XRD), the process of stabilization was examined. The results showed that salt has a major impact on the geotechnical characteristics of semi-arid soils. With the addition of sodium chloride, the maximum dry density increased and the optimal water content decreased with the increase in the added salt percentage. The liquid and plastic limits and, in turn, plasticity index reduced as the added percentage of sodium chloride increased. Furthermore, significant increase in CBR and shear strength parameters was noticed. It is therefore concluded that, the sodium chloride could be a good stabilizing agent, particularly at 20% and could be used as a sub-base material in road construction. Technical and economic advantages arise from the implementation of NaCl.

scholarly journals A GEOTECHNICAL ASSESSMENT OF USABILITY OF A ROCKSOIL MIXTURE FOR EARTH STRUCTURES

AGROFOR ◽  
2018 ◽  
Vol 2 (3) ◽  
Author(s):  
Eugeniusz ZAWISZA ◽  
Andrzej GRUCHOT
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Solid Particles ◽  
Coarse Grained ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Angle Of Internal Friction ◽  
Natural Moisture Content ◽  
Geotechnical Characteristics ◽  
Geotechnical Assessment

The subject-matter of the work is a mixture of rock and soil from the LafargeDubie mine in Rudawa, southern Poland. The conducted tests aimed at thedetermination of the geotechnical characteristics of this mixture and the evaluationof its suitability for the construction of earth embankments, in particular road ones.The range of the tests comprised determination of parameters characterisingphysical properties, such as granulometric composition, natural moisture content,density of solid particles, optimum moisture content and maximum dry density ofsolid particles, as well as mechanical ones, like shear strength. The obtained resultsshow that the tested mixture is suitable for the construction of road embankments,since as coarse-grained soil, it has a high value of the uniformity coefficient (Cu =1913). Therefore, this is very well graded soil, which provides a good compactionwhen it is built into the embankment. The natural moisture content (on average wn= 9.5%) is close to the optimum one (wopt = 8.5%). The maximum dry density ofsolid particles (ds = 2.16 gcm-3) is much higher than the minimum required (d ≥1.6 gcm-3). The values of the angle of internal friction (on average  = 36) andcohesion (c = 42 kPa) indicate great shear strength, therefore this soil can besubjected to considerable mechanical stresses.

scholarly journals POTENTIAL OF GRANITE DUST TO IMPROVE THE ENGINEERING PROPERTIES OF SOFT SOILS FOR ROAD CONSTRUCTION

2020 ◽  
Vol 2 (1) ◽  
pp. 55-61
Author(s):  
Ahmed Eltwati ◽  
Alaa Elkaseh ◽  
Fares Tarhuni ◽  
Saleh Ahmeed Buagela
Keyword(s):  
Shear Strength ◽  
Soft Soil ◽  
Base Material ◽  
Geotechnical Properties ◽  
Engineering Properties ◽  
Clay Soils ◽  
Dry Density ◽  
Direct Shear ◽  
Chemical Additives ◽  
Soft Soils

Soft soils such as clay soils, mostly if they comprise swelling minerals may produce great damage to structures, particularly when these soils are exposed to wetting and drying situations. The geotechnical properties of soft soils could be enhanced by utilizing chemical additives. In this paper, granite waste dust was used to adjust the properties of clay soils. This paper investigates the effect of granite rock dust on the geotechnical properties of soft soil. The particle size distribution, Atterberg limits, compaction, California bearing ratio (CBR) and direct shear strength characteristics of the soil when blended with various percentages of granite dust were evaluated. The findings show a great increase in the maximum dry density, optimum water content, direct shear strength and CBR with increasing the amount of granite dust. The best results obtained for CBR values were when the soils mixed with 8% granite dust. Although these findings indicate great improvement in the geotechnical parameters of clayey soils, the higher strength established is not enough for the enhanced soil to be utilized as a base material in the construction of heavily-trafficked flexible pavements. However, this modified material can be used as a base material for moderate traffic roads and as a sub-base material for high traffic roads.

scholarly journals Bearing Capacity of Soft Marine Soil Stabilization with Cockel Shell Powder (CSP)

2020 ◽  
Vol 9 (3) ◽  
pp. 1490-1497
Keyword(s):  
Bearing Capacity ◽  
Soil Stabilization ◽  
Soft Soil ◽  
Base Material ◽  
Road Construction ◽  
Dry Density ◽  
Index Test ◽  
Geotechnical Characteristics ◽  
Stabilization Technique ◽  
Marine Soil

The quality of the subgrade is depending on the geotechnical properties, strength and the stabilization technique adopted for problematic soil in order to increase the bearing value. In Malaysia, soft soil is a challenging due to very low strength value and low California Bearing Ratio (CBR) value as well. The soil stabilization process is conducted to increase bearing capacity of marine soil. An experimental works cover from identification of basic soil properties by index test, compaction test and CBR test. Though, the marine soils have to be treated and stabilized with available methods like using natural materials or additive agents. In this study, geotechnical characteristics of marine soil stabilized with CSP content were determined. The unsoaked treated marine soil stabilized with CSP was investigated. Four different compounds of the soil with 2.5, 5, 7.5 and 10% of CSP were mixed and added to determine the unsoaked CBR of the stabilized soil compounds. The results show the inclusion of CSP reduced the plasticity of the soil and highest dry density was decreased with an increase in the optimum water content. Moreover, by increasing the content of CSP the highest CBR value at 2.5 and 5.0 mm penetrations were achieved. The increasing percentage volume of water usage indicates the decreasing value of CBR. The results indicated that CSP contents have potential as a natural stabilizer for applications such as road sub-base material in road construction. The road sub-base will gain great strength with addition of CSP on marine soil

Uniaxial Compression on Salted Snow

2018 ◽  
Vol 46 (1) ◽  
pp. 16-26 ◽  
Author(s):  
Henri Giudici ◽  
Johan Wåhlin ◽  
Alex Klein-Paste
Keyword(s):  
Mechanical Properties ◽  
Sodium Chloride ◽  
Uniaxial Compression ◽  
Road Traffic ◽  
Dry Density ◽  
Chloride Salt ◽  
Road Traffic Safety ◽  
Mechanical Removal ◽  
Applied Forces ◽  
Loss Of Mass

ABSTRACT During snowfall loose snow sticks to the underlying pavement, forming a hard crust that can be difficult to remove. In order to ensure good road traffic safety, winter maintenance personnel use several operations, such as mechanical removal and chemical altering, to keep snow plowable. One chemical, commonly applied on roads, is sodium chloride (salt). Recent studies establish that very small amounts of salt are sufficient to weaken compacted snow substantially, meaning that the mechanical properties of salted snow are different from dry snow. This change in the mechanical properties of salted snow, however, has not been considered when studying tire–pavement interaction in snowy conditions. In an attempt to better understand salt snow as a material, this paper presents an experimental investigation of salted snow under uniaxial compression. The study examines the density and the loss of mass of snow after compression for different solution contents and compression speeds. Samples of snow were mixed with sodium chloride solution at different liquid contents. The snow samples were then compressed by an MTS uniaxial compression machine, up to an applied load of approximately 2 bars, roughly corresponding to the pressure applied by a car. Applied forces and dry density were measured for each test after compression. Based on the results carried out in this study, we found that: Salted snow gets a higher density after compaction compared to dry snow, also flows easier than dry snow, giving a larger loss of mass during uniaxial compression. The dry density after compaction increases with compaction speed for dry snow but decreases with compaction speed for salted snow. The effect of the solution on the compressibility and flowability of the material and its relevance for tire–pavement interaction are discussed.

Application of In Situ X-ray Absorption Spectroscopy to Study Dilute Chromium Ions in a Molten Chloride Salt

2019 ◽  
Author(s):  
Jisue Moon ◽  
Carter Abney ◽  
Dmitriy Dolzhnikov ◽  
James M. Kurley ◽  
Kevin A. Beyer ◽  
...  
Keyword(s):  
Absorption Spectroscopy ◽  
Local Structure ◽  
Chloride Salt ◽  
X Ray ◽  
Molten Chloride ◽  
Stable Species ◽  
Higher Temperature ◽  
Cr Concentration ◽  
X Ray Absorption

The local structure of dilute CrCl<sub>3</sub> in a molten MgCl<sub>2</sub>:KCl salt was investigated by <i>in situ</i> x-ray absorption spectroscopy (XAS) at temperatures from room temperature to 800<sup>o</sup>C. This constitutes the first experiment where dilute Cr speciation is explored in a molten chloride salt, ostensibly due to the compounding challenges arising from a low Cr concentration in a matrix of heavy absorbers at extreme temperatures. CrCl<sub>3</sub> was confirmed to be the stable species between 200 and 500<sup>o</sup>C, while mobility of metal ions at higher temperature (>700<sup>o</sup>C) prevented confirmation of the local structure.

scholarly journals The performance of ultra-lightweight foamed concrete incorporating nanosilica

2021 ◽  
Vol 21 (2) ◽  
Author(s):  
Mohamed Abd Elrahman ◽  
Pawel Sikora ◽  
Sang-Yeop Chung ◽  
Dietmar Stephan
Keyword(s):  
Wall Thickness ◽  
Probabilistic Approach ◽  
Drying Shrinkage ◽  
Dry Density ◽  
Optimal Dosage ◽  
X Ray ◽  
Mechanical And Physical Properties ◽  
Fresh State ◽  
Foamed Concrete ◽  
The Stability

AbstractThis paper aims to investigate the feasibility of the incorporation of nanosilica (NS) in ultra-lightweight foamed concrete (ULFC), with an oven-dry density of 350 kg/m3, in regard to its fresh and hardened characteristics. The performance of various dosages of NS, up to 10 wt.-%, were examined. In addition, fly ash and silica fume were used as cement replacing materials, to compare their influence on the properties of foamed concrete. Mechanical and physical properties, drying shrinkage and the sorption of concrete were measured. Scanning electron microscopy (SEM) and X-ray microcomputed tomography (µ-CT) and a probabilistic approach were implemented to evaluate the microstructural changes associated with the incorporation of different additives, such as wall thickness and pore anisotropy of produced ULFCs. The experimental results confirmed that the use of NS in optimal dosage is an effective way to improve the stability of foam bubbles in the fresh state. Incorporation of NS decrease the pore anisotropy and allows to produce a foamed concrete with increased wall thickness. As a result more robust and homogenous microstructure is produced which translate to improved mechanical and transport related properties. It was found that replacement of cement with 5 wt.-% and 10 wt.-% NS increase the compressive strength of ULFC by 20% and 25%, respectively, when compared to control concrete. The drying shrinkage of the NS-incorporated mixes was higher than in the control mix at early ages, while decreasing at 28 d. In overall, it was found that NS is more effective than other conventional fine materials in improving the stability of fresh mixture as well as enhancing the strength of foamed concrete and reducing its porosity and sorption.

Chemical weathering in semi-arid soils of the Russian plain

CATENA ◽  
2021 ◽  
Vol 206 ◽  
pp. 105554
Author(s):  
P.I. Kalinin ◽  
I.Yu. Kudrevatykh ◽  
V.V. Malyshev ◽  
L.S. Pilguy ◽  
A.V. Buhonov ◽  
...  
Keyword(s):  
Chemical Weathering ◽  
Russian Plain ◽  
Arid Soils ◽  
Semi Arid
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