Physico-Chemical Characterization Of Lime Stabilized Tropical Kaolin Clay

2015 ◽  
Vol 72 (3) ◽  
Author(s):  
Khitam Abdul Hussein Saeed ◽  
Khairul Anuar Kassim ◽  
Nor Zurairahetty Mohd Yunus ◽  
Hadi Nur
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Soft Clay ◽  
Chemical Characterization ◽  
Kaolin Clay ◽  
X Ray Diffraction ◽  
Lime Content ◽  
Physico Chemical ◽  
Content Factor

Lime stabilization is one of the techniques used to improve the mechanical properties, particularly the strength of soft clay soil. However the effectiveness of lime at long term is still ambiguous. This paper aims to determine the suitability of lime for stabilizing tropical kaolin clay soils, and to assess typical changes in soil structure due to mineralogical influences at different during period and lime content in both short and long term. The microstructure characterizations have been investigated using x-ray diffraction (XRD), and Field Emission Scanning Electron Microscopy (FESEM). Furthermore, to illustrate the effect of lime on the strength, series of laboratory tests were carried out by unconfined compressive strength. The results indicated that the addition of lime resulted in an improvement in compaction properties. In addition, the unconfined compressive strength (UCS) of stabilized clay has increased with the addition of lime. The influence of the time factor on the development of strength lime treated samples was equally proportional with the lime content factor. The formation of calcium aluminate silicate hydrate (CASH) was observed from the XRD test after 200 days, and the presence of the cementious products were further verified in FESEM analysis. It is therefore, proved the effectiveness of lime to stabilize kaolin clay in long term duration.

scholarly journals Macroscopic and Microscopic Mechanisms of Cement-Stabilized Soft Clay Mixed with Seawater by Adding Ultrafine Silica Fume

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Qiang Li ◽  
Jie Chen ◽  
Qian Shi ◽  
Shihao Zhao
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Soft Clay ◽  
Chemical Characterization ◽  
Test Results ◽  
X Ray Diffraction ◽  
Compressive Strength Test ◽  
Ultrafine Silica ◽  
Stabilized Soil ◽  
Physical And Chemical

The strength of the cement-stabilized soil can be improved by the use of seawater. Compressive strength test results show that the strength of cement-stabilized soil mixed with seawater is 50% greater than that mixed with freshwater at the 90th day. However, the application is limited because the expansion of the cement-stabilized soil mixed with seawater increases significantly. A kind of ultrafine silica fume was added into the cement-stabilized soil to inhibit swelling of the cement-stabilized soil with seawater. The expansion of cement-stabilized soil mixed with seawater by adding ultrafine silica fume is close to that of cement-stabilized soil mixed with freshwater. With the addition of ultrafine silica fume, the unconfined compressive strength increases by close to 6.5% compared with seawater alone at the 90th day. The mechanisms of adding ultrafine silica fume into the cement-stabilized soil mixed with seawater are revealed by several physical and chemical characterization parameters, such as specific gravity, unbound water content, surface morphology seen with SEM, and crystal products by X-ray diffraction tests. The results show that the crystal growth is an important factor, affecting the strength and expansion of cement-stabilized soil mixed with seawater.

Experimental Research on Engineering Property of Heavy Metal-Contaminated Kaolinite

2011 ◽  
Vol 94-96 ◽  
pp. 1921-1929 ◽  
Author(s):  
Zhi Bin Liu ◽  
Xin Ma ◽  
Wen Long Dai
Keyword(s):  
Heavy Metal ◽  
Compressive Strength ◽  
Electrical Resistivity ◽  
Metal Ions ◽  
Unconfined Compressive Strength ◽  
Heavy Metal Ions ◽  
Engineering Property ◽  
Contamination Concentration ◽  
Expansion Capacity

Due to release and accumulation of industrial contaminants in natural soil in some regions, and the long-term interaction between leachate and clay which is adopted as isolation material of contaminants, the engineering property variation of clay soils after having been polluted by heavy metal ions gradually has drawn more and more attention of environmental geotechnical engineers. With relatively high chemical stability and low expansion coefficient kaolinite is widely distributed and usually used in engineering practice. In this research, Pb, Zn, and Cu-contaminated kaolinite specimens of controlled initial dry density and water content were manually prepared through static compaction. Then expansion capacity, unconfined compression, electrical resistivity and one-dimensional consolidation tests were conducted. It is found that the expansion capacity of contaminated kaolinite is influenced by the type and concentration of heavy metal ion. The unconfined compressive strength of heavy metal-contaminated kaolinite is decreased in a short period, but it may increase in a long term. Unconfined compressive strength of the same type of heavy metal-contaminated kaolinite will change with the contamination concentration. The electrical resistivity of kaolinite would be decreased when contaminated by heavy metal ions. The higher the contamination concentration is, the lower the electrical resistivity will be. All the compression indexes of heavy metal-contaminated kaolinite become lower than that of the clean kaolinite, and it also depends on both the type of heavy metal and contamination concentration. For the three types of heavy metal ions, Pb has the greatest influence on the engineering property of kaolinite, while the effects of Zn and Cu are quite similar.

scholarly journals Microbial-Induced Carbonate Precipitation for Strengthening Soft Clay

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
J. Z. Xiao ◽  
Y. Q. Wei ◽  
H. Cai ◽  
Z. W. Wang ◽  
T. Yang ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Unconfined Compressive Strength ◽  
Soft Clay ◽  
High Water ◽  
High Water Content ◽  
Carbonate Precipitation ◽  
Experimental Conditions ◽  
Strength Enhancement ◽  
Complex Chemical Composition

Currently, calcite produced in sediments by microbial-induced carbonate precipitation (MICP) is mainly used as a strengthening binder in sand because sands are porous and have good permeability. Conventional wisdom does not consider MICP to be suitable for use in soft clay because of the clay particles’ small size and its minimal porosity. Because of the clay’s high water content and complex chemical composition, very little research has been done and not much is known about the use of MICP in soft clay for strength enhancement. For this paper, soft clay specimens were prepared by mixing a solution containing Sporosarcina pasteurii bacteria, solutions with different concentrations of nutrient salts, and soft clay. Unconfined compressive strength tests were carried out on these specimens after they had cured for 28 days in a moisture-controlled environment. These laboratory tests were used to study the chemical reactions, the clay’s strength, and other influencing factors. The results are as follows: (1) directly mixing a S. pasteurii solution, nutrient salts, and soft clay considerably improves the uniformity of the spatial distribution of the bacteria and the nutrients in the soft clay. Directly mixing these constituents promotes the formation of calcium carbonate and greatly simplifies soft clay sample preparation. (2) It is feasible to use MICP to increase the strength of soft clay. Compared to control specimens cured under the same conditions but without introduced nutrients and bacteria solution, the unconfined compressive strength of MICP-treated specimens can be increased by as much as 2.42 times to an unconfined compressive strength of 43.31 kPa. The water content in MICP-treated specimens was significantly reduced by the MICP reactions and in one case decreased from 40% to 30.73%. (3) The strength enhancement of microbially solidified soft clay is the result of two processes: urea hydration catalyzed by enzymes consumes water in the clay and the bacterially precipitated calcite forms in the sediment’s pores. (4) The micro-organism-produced calcite in the soft clay increases the calcite abundance from 0% to as much as 3.5%. (5) The MICP-treated strength of soft clay varies with the concentration of the nutrients provided. For the experimental conditions used for this paper, the optimum concentration of the CaCl2·2H2O and CH4N2O nutrients is 0.5 mol/L.

Influence of Curing Pressure on Unconfined Compressive Strength of Cemented Clay

2018 ◽  
Vol 928 ◽  
pp. 263-268 ◽  
Author(s):  
Anuchit Uchaipichat
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Cement Content ◽  
Soft Clay ◽  
Peak Stress ◽  
Confining Pressure ◽  
Compression Tests ◽  
Unconfined Compression ◽  
Soil Cement ◽  
Curing Pressure

The soil-cement columns are generally installed and cured in the soft clay layers under confining pressure. The strength of the soil-cement columns may be influenced by confining pressure during curing period. In this study, the main objective was to study the influence of curing pressure on unconfined compressive strength of cemented clay. A series of unconfined compression tests was performed on a cement admixed clay sample cured under pressure values of 0 kPa (atmospheric pressure), 25kPa, 50kPa and 100 kPa using a typical unconfined compression equipment. The test samples with values of cement content of 0.5, 1.0 and 2.0 percent were cured for 28 days.The stress-strain curves obtained from all tests show a peak value of stress. The unconfined compressive strength or peak stress obviously increased with increasing cement content for all curing pressure conditions. It can be observed that the strength of samples gradually increased with curing pressure for cement content of 0.5 percent. For cement contents of 1.0 and 2.0 percent, the strengths of samples cured under pressures of 25 kPa dramatically increased from the strength of samples cured without pressure (0 kPa), however, the strengths of samples for curing pressures of 25, 50 and 100 kPa were not clearly different.

scholarly journals Evaluation Method for Thixotropy of Clay Subjected to Unconfined Compressive Test

2021 ◽  
Vol 9 ◽  
Author(s):  
Bin Tang ◽  
Biaohe Zhou ◽  
Liang Xie ◽  
Jianfeng Yin
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Evaluation Method ◽  
Curing Time ◽  
Recovery Coefficient ◽  
Undisturbed Soil ◽  
Structural Recovery ◽  
The Index System ◽  
The Relationship

Thixotropy is a hot topic in the field of rheology of dispersed systems. Studying the quantitative index and evaluation method for thixotropy of clay is of great significance to evaluate the safety of foundation under long-term load. To explore the index system and classification methods for the thixotropy of clay, unconfined compressive strength tests were carried out on three groups of undisturbed soil and remolded soil that were cured at different times after remodeling of the Zhanjiang Formation in China to obtain the unconfined compressive strength values of the samples and establish the relationship between unconfined compressive strength and curing time of the remodeled soil. The concept of thixotropic sensitivity is introduced to reflect the relationship between thixotropy and structure. According to the relationship between thixotropy sensitivity and curing time and its logarithmic value, two indexes of structural recovery coefficient K and structural recovery index Ke were established to evaluate the thixotropy of structural clay in the Zhanjiang Formation. Following the structural classification method of soil, the boundary values of structural recovery coefficients KI and KII are calculated to classify the thixotropy of soil. When the value of K is less than that of KI, the thixotropy of soil is weak. When the value of K is greater than that of K but less than that of KII, the thixotropy of soil is moderate. When the value of K is greater than that of KII, the thixotropy of soil is strong. The method is used to discuss the thixotropy of soil in the literature, and the rationality of the method is verified. Results show that this method can be used to preliminary classify the thixotropy of soil.

scholarly journals Evaluation of the long-term compressive strength development of the sewage sludge ash/metakaolin-based geopolymer

2021 ◽  
Vol 71 (343) ◽  
pp. e254
Author(s):  
D. Istuque ◽  
L. Soriano ◽  
M.V. Borrachero ◽  
J. Payá ◽  
J.L. Akasaki ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Sewage Sludge ◽  
Strength Development ◽  
X Ray Diffraction ◽  
Sewage Sludge Ash ◽  
Dense Microstructure ◽  
Compressive Strength Development ◽  
Physicochemical Characterisation ◽  
Sludge Ash

This paper aimed to evaluate the long-term compressive strength development of the sewage sludge ash/metakaolin (SSA/MK)-based geopolymer. SSA/MK-based geopolymeric mortars and pastes were produced at 25ºC with different SSA contents (0 - 30 wt.%). Compressive strength tests were run within the 3-720 curing days range. A physicochemical characterisation (X-ray diffraction and scanning electron microscopy) was performed in geopolymeric pastes. All the geopolymeric mortars presented a compressive strength gain with curing time. The mortars with all the SSA evaluated contents (10, 20, 30 wt.%) developed a compressive strength over 40 MPa after 720 curing days at 25ºC. The maximum compressive strength of the mortars with SSA was approximately 61 MPa (10 wt.% of SSA), similarly to the reference mortar (100% MK-based geopolymer). The microstructure analyses showed that the SSA/MK-based geopolymer presented a dense microstructure with N-A-S-H gel formation.

UNCONFINED COMPRESSIVE STRENGTH AND MICROSTRUCTURE OF CLAY SOIL STABILISED WITH BIOMASS SILICA

2015 ◽  
Vol 77 (11) ◽  
Author(s):  
Fauziah Kasim ◽  
Aminaton Marto ◽  
Nur Amalina Abdul Rahman ◽  
Choy Soon Tan
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Clay Soil ◽  
Soft Soil ◽  
Soft Clay ◽  
Engineering Properties ◽  
Test Results ◽  
Electron Microscopic ◽  
Treated Sample ◽  
Basic Characteristics

This study presents the Unconfined Compressive Strength (UCS) and microstructure of clay soil stabilized with locally made Biomass Silica (BS) in the form of SH-85. Since the construction of highway on soft soil raises many problems due to its low strength, understanding about the basic characteristics of soft clay and mixed with BS, play important role for improving the strength of the soft clay. The study carried out had the specific objectives to determine engineering properties of soft clay, to investigate the UCS of soft clay treated with BS and to analyze microstructure of the soft soil treated by BS with respect to various curing periods. In this study, 30 samples of clay soil were prepared under various curing periods (0, 7, 14 and 28 days) and mixed with BS at various percentages (5 %, 7 % and 9 %). The test results show that BS can increase the strength of the clay soil. The 9% BS treated sample for 7 days curing time achieved UCS of 710 kPa. This was approximately 6 times greater than that of untreated soil strength. The highest strength was 1216 kPa at 28 days curing for soil mixed with 9% BS. The images of Scanning Electron Microscopic show that the voids of the clay would filled by the new component resulted by the reaction of BS stabilizer with the natural clay samples. This led to a continuous soil fabric resulting with stronger and denser soil.

scholarly journals The influence of soft clay saturation characteristics on unconfined compressive strength in Guangdong-Hong Kong-Macao Greater Bay Area

2021 ◽  
Vol 293 ◽  
pp. 02011
Author(s):  
DaShu Guan ◽  
JiaXi Zheng ◽  
WenHao Huang ◽  
JunZhi Zhong ◽  
WenWen Du ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Gas Phase ◽  
Unconfined Compressive Strength ◽  
Shear Failure ◽  
Soft Clay ◽  
Plastic Shear ◽  
Bay Area ◽  
Saturated Clay ◽  
Unsaturated Clay ◽  
Saturated Soft Clay

In order to study the influence of saturated characteristics of soft clay on unconfined compressive strength, the soft clay of Guangdong-Hong Kong-Macao Bay Area is taken as the research object, comparing and contrasting on unconfined compression test of saturated clay and unsaturated clay in laboratory, studying the variation law of unconfined compressive strength and sensitivity of unsaturated and saturated soft clay. The test results show that: 1. During the failure of unsaturated soft clay samples, oblique fractures appear, showing brittle shear failure, while the saturated clay samples appear constant bulging in the middle, and finally a “cross” is broken in the central bulging part, showing plastic shear failure.2. The unconfined compressive strength of unsaturated clay is about 10kPa higher than that of saturated soft clay, and its corresponding sensitivity is also about 0.4 higher. It can be shown that the soil saturation has a certain influence on the soil strength. The difference between saturated soil and unsaturated soil is the existence of gas phase. To be more precise, the existence of gas phase in unsaturated soil, i.e. the existence of suction, makes the soil stronger and presents the brittle shear failure form, while the saturated soil basically presents the plastic shear failure form.

scholarly journals Synthesis, Crystal Structures, Hirshfeld Surfaces Analysis and Physico-Chemical Characterization of Two New ZnII and CdII Halidometallates

2021 ◽  
Author(s):  
ali rayes ◽  
Manel moncer ◽  
Irene Ara ◽  
Dege Necmi ◽  
Brahim Ayed
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Chemical Characterization ◽  
Chair Conformation ◽  
Spectroscopic Techniques ◽  
X Ray Diffraction ◽  
X Ray ◽  
3 Dimensional ◽  
Physico Chemical ◽  
Ft Ir

Abstract Two new organic-inorganic hybrid materials, based on 1,3-CycloHexaneBis-(Methyl Amine), abbreviated CHBMA, namely(H2CHBMA)ZnCl4.2H2O (CP1) and (H2CHBMA)CdI4.2H2O (CP2), have been synthesized under mild conditions in acidic media and characterized by single-crystal X-ray diffraction, spectroscopic techniques (13C NMR, FT-IR, RAMAN) and thermal analysis. The crystal structures of the two compounds were solved by single-crystal X-ray diffraction methods. Both compounds show a 3-dimensional supramolecular structure directed by various interactions between tetrahalidometallate anions (ZnCl42-, CdI42-), water molecule and organic cations (H2CHBMA)2+. For both compounds, the cyclohexane ring of the template cation is in a chair conformation with the methyl-ammonium substituent in the equatorial positions and the two terminal ammonium groups in a cis conformation but with two different orientations (upward for CP1 and downward for CP2) which influences the supramolecular architecture of the two structures. Hirshfeld surface analysis and the associated two-dimensional finger print plots were used to explore and quantify the intermolecular interactions in the crystals.

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