scholarly journals An Investigation into Performance of Cement-Stabilized Kaolinite Clay with Recycled Seashells Exposed to Sulphate

2020 ◽  
Vol 12 (20) ◽  
pp. 8367
Author(s):  
Amin Chegenizadeh ◽  
Mahdi Keramatikerman ◽  
Faizan Afzal ◽  
Hamid Nikraz ◽  
Chee Keong Lau
Keyword(s):  
Magnesium Sulphate ◽  
Dry Density ◽  
X Ray Diffraction ◽  
Maximum Dry Density ◽  
Kaolinite Clay ◽  
X Ray ◽  
Sulphate Concentration ◽  
Stabilized Soil ◽  
Key Issues ◽  
Negative Impacts

Sulphate attack is one of the key issues in geotechnical engineering. This study aims to investigate the efficacy of the seashell to reduce negative impacts of the magnesium sulphate concentration on the cement-stabilized clay mixtures by performing a series of unconfined compressive strength (UCS) tests. Three percent of cement (3, 5 and 7%) was utilized in this study. In addition, the benchmark and exposed specimens were cured for 7, 14, and 28 days before testing and exposure, respectively. A series of the compaction tests were conducted and the optimum moisture content (OMC) and maximum dry density (MDD) values were achieved. In the next stage, the UCS tests were performed on the specimens containing 10, 20, or 30% seashell contents and the specimens were exposed to sulphate concentration. Scanning electron microscope morphology had indicated that seashells are a suitable replacement for cement. Qualitative X-ray diffraction had shown that the presence of magnesium sulphate reduces the formation of calcium silicate hydrate, which causes durability issues in cement-stabilized soils. The results indicated that seashell is effective to improve the sulphate resistance of cement-stabilized soil.

scholarly journals Development of a Novel Multifunctional Cementitious-Based Geocomposite by the Contribution of CNT and GNP

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 961
Author(s):  
Mohammadmahdi Abedi ◽  
Raul Fangueiro ◽  
António Gomes Correia
Keyword(s):  
Optimum Concentration ◽  
Dry Density ◽  
Maximum Dry Density ◽  
X Ray ◽  
Freeze Thaw ◽  
Climatic Cycles ◽  
Negative Impacts ◽  
Compaction Method ◽  
Hybrid Carbon ◽  
Standard Compaction

In this study, a self-sensing cementitious stabilized sand (CSS) was developed by the incorporation of hybrid carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) based on the piezoresistivity principle. For this purpose, different concentrations of CNTs and GNPs (1:1) were dispersed into the CSS, and specimens were fabricated using the standard compaction method with optimum moisture. The mechanical and microstructural, durability, and piezoresistivity performances, of CSS were investigated by various tests after 28 days of hydration. The results showed that the incorporation of 0.1%, 0.17%, and 0.24% CNT/GNP into the stabilized sand with 10% cement caused an increase in UCS of about 65%, 31%, and 14%, respectively, compared to plain CSS. An excessive increase in the CNM concentration beyond 0.24% to 0.34% reduced the UCS by around 13%. The addition of 0.1% CNMs as the optimum concentration increased the maximum dry density of the CSS as well as leading to optimum moisture reduction. Reinforcing CSS with the optimum concentration of CNT/GNP improved the hydration rate and durability of the specimens against severe climatic cycles, including freeze–thaw and wetting–drying. The addition of 0.1%, 0.17%, 0.24%, and 0.34% CNMs into the CSS resulted in gauge factors of about 123, 139, 151, and 173, respectively. However, the Raman and X-ray analysis showed the negative impacts of harsh climatic cycles on the electrical properties of the CNT/GNP and sensitivity of nano intruded CSS.

CLAYEY SOIL TREATED BY CEMENT AND QUICKLIME BY MICROSTRUCTURE: A MINERALOGICAL ANALYSIS

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Husam Hikmat Baqir ◽  
Aqeel Al-Adili ◽  
Kawther Al-Soudany ◽  
Ali Shareef
Keyword(s):  
Clay Soil ◽  
Clayey Soil ◽  
Dry Weight ◽  
Dry Density ◽  
Hydration Reaction ◽  
X Ray Diffraction ◽  
Mineralogical Analysis ◽  
Maximum Dry Density ◽  
X Ray ◽  
Scanning Electron

Soft clayey soil was treated by a combination of cement (PC) and Quicklime (LQ) in order to modify and stability. This study shows an improvement of clay soil brought from Garma Ali site in the Al Basra governorate, Iraq. The PC was added in percentages of 0, 2, 4, 6, 8, and 10%, and LQ was added to 2 and 4%, of dry weight. Also, this research used Microstructure Analysis by Scanning Electron Microscope (SEM) testing and Mineralogical Analysis by X-Ray Diffraction (XRD) testing on the examination soil treated with mix between cement (PC) and Quicklime (LQ) for the purpose of knowing the reasons for the increase in the shear strength and decrease maximum dry density. Through the micrographs that result from the scanning electron microscoping and the curves of X-ray that demonstrate presentence, the formation of the hydration reaction product (CSH gel) shows tiny bristle (rod) crystals. The CSH gel and the tiny bristle (rod) crystals worked on coating and contact the particles together. The micrographs for soils treated with (2% LQ + 10% PC) show an increase in the amount hydrated gel (CSH) compared to the soil treated with 6% PC and 2% LQ and 8% PC and 4% LQ, but the number of bristle-like crystals decreases compared to soil treated by 8% PC and 4% LQ.

scholarly journals Strength Performance and Microstructure of Calcium Sulfoaluminate Cement-Stabilized Soft Soil

2021 ◽  
Vol 13 (4) ◽  
pp. 2295
Author(s):  
Hailong Liu ◽  
Jiuye Zhao ◽  
Yu Wang ◽  
Nangai Yi ◽  
Chunyi Cui
Keyword(s):  
Soft Soil ◽  
Hydration Product ◽  
X Ray Diffraction ◽  
Calcium Sulfoaluminate Cement ◽  
Strength Performance ◽  
X Ray ◽  
Calcium Sulfoaluminate ◽  
Stabilized Soil ◽  
Calcium Silicates ◽  
Hydrated Calcium

Calcium sulfoaluminate cement (CSA) was used to stabilize a type of marine soft soil in Dalian China. Unconfined compressive strength (UCS) of CSA-stabilized soil was tested and compared to ordinary Portland cement (OPC); meanwhile the influence of amounts of gypsum in CSA and cement contents in stabilized soils on the strength of stabilized soils were investigated. X-ray diffraction (XRD) tests were employed to detect generated hydration products, and scanning electron microscopy (SEM) was conducted to analyze microstructures of CSA-stabilized soils. The results showed that UCS of CSA-stabilized soils at 1, 3, and 28 d firstly increased and then decreased with contents of gypsum increasing from 0 to 40 wt.%, and CSA-stabilized soils exhibited the highest UCS when the content of gypsum equaled 25 wt.%. When the mixing amounts of OPC and CSA were the same, CSA-stabilized soils had a significantly higher early strength (1 and 3 d) than OPC. For CSA-stabilized soil with 0 wt.% gypsum, monosulfate (AFm) was detected as a major hydration product. As for CSA-stabilized soil with certain amounts of gypsum, the intensity of ettringite (Aft) was significantly higher than that in the sample hydrating without gypsum, but a tiny peak of AFm also could be detected in the sample with 15 wt.% gypsum at 28 d. Additionally, the intensity of AFt increased with the contents of gypsum increasing from 0 to 25 wt.%. When contents of gypsum increased from 25 to 40 wt.%, the intensity of AFt tended to decrease slightly, and residual gypsum could be detected in the sample with 40 wt.% gypsum at 28 d. In the microstructure of OPC-stabilized soils, hexagonal plate-shaped calcium hydroxide (CH) constituted skeleton structures, and clusters of hydrated calcium silicates (C-S-H) gel adhered to particles of soils. In the microstructure of CSA-stabilized soils, AFt constituted skeleton structures, and the crystalline sizes of ettringite increased with contents of gypsum increasing; meanwhile, clusters of the aluminum hydroxide (AH3) phase could be observed to adhere to particles of soils and strengthen the interaction.

Physico-Chemical and Morphological Changes of Sayong Kaolinite Clay Treated with Sulphuric Acid for Enzyme Immobilization

2013 ◽  
Vol 832 ◽  
pp. 589-595 ◽  
Author(s):  
N.A. Edama ◽  
A. Sulaiman ◽  
K.H. Ku Hamid ◽  
M.N. Muhd Rodhi ◽  
Mohibah Musa ◽  
...  
Keyword(s):  
Surface Area ◽  
Sulphuric Acid ◽  
Enzyme Immobilization ◽  
Morphological Changes ◽  
Chemical Properties ◽  
X Ray Diffraction ◽  
Kaolinite Clay ◽  
X Ray ◽  
Mineral Oxides ◽  
Physico Chemical

This study analyzed the effects of sulphuric acid (H2SO4) treatment on pysico-chemical properties and morphological changes of clay obtained from Sg. Sayong, Perak. The clay was ground and sieved to <150μm and treated with different concentrations of H2SO4. The treatment was completed by refluxing the clay with different concentration of H2SO4 (1M, 5M and 10M ) at 100 °C for 4 hours and followed by calcination at 500 °C for 1 hour. The physic-chemical properties and morphological changes of the untreated and treated clay were compared using Surface Area Analyser, X-Ray Diffraction (XRD), Field Emission Scanning Electron Micrograph (FESEM), X-Ray Diffraction (XRD) and Fourier Transformed Infrared Spectroscopy (FTIR). The results showed that acid treatment of 5M increased the surface area from 25 m2/g to 75 m2/g and the pore volume increased from 0.1518 cc/g to 0.3546 cc/g. The nanopore size of the clay decreased from 24.8 nm to 19.4 nm after treated with acid. This can be explained due to the elimination of the exchangeable cations and generation of microporosity. The results of XRF showed SiO2 increased from 58.34% to 74.52% and Al2O3 reduced from 34.6% to 18.31%. The mineral oxides such as Fe2O3, MgO, CaO, K2O and TiO2 also reduced. This concluded that H2SO4 treatment has led to significant removal of octahedral Al3+, Fe3+ cations and other impurities. In conclusion, this study showed the physico-chemical properties and morphology of Sayong clay were improved once treated with H2SO4 and therefore suggests better supporting material for enzyme immobilization.

Effect of Lime on Compaction, Strength and Consolidation Characteristics of Pontian Marine Clay

2015 ◽  
Vol 72 (3) ◽  
Author(s):  
Siaw Yah Chong ◽  
Khairul Anuar Kassim
Keyword(s):  
Construction Material ◽  
Soft Clay ◽  
Engineering Properties ◽  
Dry Density ◽  
Marine Clay ◽  
Maximum Dry Density ◽  
Stabilization Phase ◽  
Compaction Curve ◽  
Stabilized Soil

Marine clay is a problematic construction material, which is often encountered in Malaysian coastal area. Previous researchers showed that lime stabilization effectively enhanced the engineering properties of clay. For soft clay, both strength and consolidation characteristics are equally important to be fully understood for design purpose. This paper presented the effect of lime on compaction, strength and consolidation characteristics of Pontian marine clay. Compaction, unconfined compression, direct shear, Oedometer and falling head permeability tests were conducted on unstabilized and lime stabilized samples at various ages. Specimens were prepared by compaction method based on 95 percent maximum dry density at the wetter side of compaction curve. It was found that lime successfully increased the strength, stiffness and workability of Pontian marine clay; however, the permeability was reduced. Unconfined compressive strength of stabilized soil was increased by 49 percent at age of 56 days whereas compressibility and permeability was reduced by 48 and 67 percent, respectively. From laboratory tests, phenomenon of inconsistency in engineering characteristics was observed for lime stabilized samples below age of 28 days. This strongly proved that lime stabilized soil underwent modification phase before stabilization phase which provided the long term improvement.

scholarly journals Dielectric and electrical properties of a mullite/glass composite from a kaolinite clay/mica-rich kaolin waste mixture

Cerâmica ◽  
2019 ◽  
Vol 65 (373) ◽  
pp. 117-121 ◽  
Author(s):  
J. P. F. Grilo ◽  
H. P. A. Alves ◽  
A. J. M. Araújo ◽  
R. M. Andrade ◽  
R. P. S. Dutra ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Glassy Phase ◽  
Low Cost ◽  
Microstructural Characterization ◽  
Reactive Sintering ◽  
X Ray Diffraction ◽  
Glass Composite ◽  
Kaolinite Clay ◽  
X Ray ◽  
Waste Mixture

Abstract A mullite/glass composite has been prepared by reactive sintering of a kaolinite clay/mica-rich kaolin waste mixture with 25 wt% waste. Phase composition, microstructure, dielectric and electrical properties of the composite fired at 1400 °C were evaluated by X-ray diffraction, scanning electron microscopy and impedance spectroscopy (between 25 and 600 °C in air). The microstructural characterization showed the attainment of dense samples composed of acicular (orthorhombic) mullite (47.6 wt%), glassy phase (50.1 wt%), and residual quartz (2.3 wt%). Electrical conductivity (1.9x10-8 S/cm at 300 °C), dielectric constant (6.7 at 1 MHz, 25 °C) and dielectric loss (0.024 at 1 MHz, 25 °C) results gave evidence that the mullite/glass composite is a promising low-cost material for commercial use in electronics-related applications.

Compressive Strength Analysis of Ionic Soil Stabilizer Improving Soil

2015 ◽  
Vol 667 ◽  
pp. 341-346 ◽  
Author(s):  
Jue Qiang Tao ◽  
Wen Yan Lin ◽  
Xiao Hua Luo ◽  
Xin Qiu ◽  
Jin Hong Wu
Keyword(s):  
Compressive Strength ◽  
Strength Analysis ◽  
Dry Density ◽  
Optimal Dosage ◽  
Maximum Dry Density ◽  
Soil Stabilizer ◽  
Limit Test ◽  
Stabilized Soil ◽  
Compaction Degree ◽  
Curing Age

To explore the ionic liquid soil stabilizer improved soil mechanical properties, this experiment conducted liquid-plastic limit test and compaction test. On the basis of determining the optimal dosage of ionic soil stabilizer and mastering different mixture optimum moisture content and maximum dry density, the standard sample which consists of the Zhejiang red-brown clay and curing material including ionic soil stabilizer, cement and lime carried out the unconfined compressive strength test in different curing age and compaction degree. This paper analyzed the change reason of compaction and curing age about the stabilized soil. The results show that the ionic soil stabilizer has a significant effect on the compressive strength improvement of stabilized soil. Compared stabilized soil with traditional treatment soil, the compressive strength of stabilized soil has improved obviously with the increase of curing age and compaction degree. Research findings provide useful technical support and practice basis for promoting and applying ionic soil stabilizer in infrastructure construction.

Sulphate resistance of silica fume blended mortars exposed to various sulphate solutions

2003 ◽  
Vol 30 (4) ◽  
pp. 625-636 ◽  
Author(s):  
Han-Young Moon ◽  
Seung-Tae Lee ◽  
Seong-Soo Kim
Keyword(s):  
Silica Fume ◽  
Magnesium Sulphate ◽  
Mercury Intrusion Porosimetry ◽  
Length Change ◽  
Sodium Sulphate ◽  
X Ray Diffraction ◽  
Replacement Ratio ◽  
Mortar Specimen ◽  
X Ray ◽  
Strength Deterioration

The different performances of silica fume blended mortars placed in various sulphate-bearing exposure conditions were investigated. Experimental study was carried out on mortars immersed in 5% sodium sulphate, 5% magnesium sulphate, and mixed 5% sodium sulphate and 5% magnesium sulphate solutions for 270 d of sulphate exposure. Another variable was the replacement ratio of cement with silica fume (0, 5, 10, and 15% of the cement by weight). The results showed conclusively that silica fume should be given serious consideration for use in sulphate environments. In other words, in a sodium sulphate solution, silica fume showed a beneficial effect on mitigating compressive strength reduction and length change of mortars. However, the strength deterioration factor of the mortar specimen with some silica fume content (especially 15% of the cement by weight) was greater than that of the mortar specimen without silica fume under Mg2+ ion oriented attack. These different sulphate deterioration mechanisms are presented in the study. Microstructural investigations such as X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDXA), and mercury intrusion porosimetry (MIP) were also used to support the explanation for these mechanisms.Key words: sodium sulphate, magnesium sulphate, silica fume, strength deterioration factor, length change.

scholarly journals Improvement of cement stabilized structural lateritic with pulverized snail shell

2019 ◽  
Vol 14 (2) ◽  
pp. 95-106
Author(s):  
Oluwaseun Adetayo ◽  
Olugbenga Amu ◽  
Sunday Alabi
Keyword(s):  
Cement Content ◽  
Soil Classification ◽  
Soil Samples ◽  
Lateritic Soil ◽  
Partial Replacement ◽  
Dry Density ◽  
Maximum Dry Density ◽  
Snail Shell ◽  
Foundation Construction ◽  
Stabilized Soil

AbstractThis study investigated the suitability of pulverized snail shell (PSS) as partial replacement of cement stabilized soil in foundation constructions. Preliminary and engineering tests were carried out on the soil samples. The optimum cement content fixed at 11% in correlation to Unified Soil Classification System, the PSS was introduced at varying percentages of 2%, 4%, 6%, 8% and 10%. Results revealed that, addition of PSS and 11% cement to lateritic soil caused a reduction in both liquid limits and plasticity index and an increased in plastic limits for all samples. Engineering tests showed the maximum dry density at optimum cement increased from 1493.34 ± 103.58 kg.m−3 to 1632 ± 435.81 kg.m−3 for sample A; 1476.77 ± 367.51 kg.m−3 to 1668 ± 202.58 kg.m−3 for sample B; 1460.77 ± 623.58 kg.m−3 to 1651 ± 135.45 kg.m−3 for sample C. The CBR recorded highest value at 4%PSS optimum cement for all samples. The addition of pulverized snail shell increased the strength of cement stabilized lateritic soil for structural foundation construction.

Influence of Recycled Concrete Powder (RCP) and Recycled Brick Powder (RBP) on the Physical/Mechanical Properties and Durability of Raw Soil

Coatings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1475
Author(s):  
Li’an Zhou ◽  
Yang Liu ◽  
Jiacheng Lu ◽  
Wenjuan Zhou ◽  
Hui Wang
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Recycled Concrete ◽  
Dry Density ◽  
X Ray Diffraction ◽  
X Ray ◽  
Freeze Thaw ◽  
Performance Change ◽  
Brick Powder ◽  
Research Findings

The influence of recycled concrete powder (RCP) and recycled brick powder (RBP) on the dry density, optimal water content, and compressive strength of raw soil materials was investigated in this study. Moreover, the following resistance of freeze–thaw cycles was also considered. Additionally, X-ray diffraction (XRD) and scanning electron microscope (SEM) were selected to detect its mineral composition and observe the microstructure, further revealing the mechanism of performance change. The mass ratios of recycled concrete powder and recycled brick powder were 2% ~ 14%. Results showed that the dry density decreased and the optimal water content increased with the increasing dosage of recycled concrete powder and recycled brick powder. When the dosage of RCP or RBP was lower than 14%, raw soil with RCP showed higher optimal water content and lower dry density. However, when the dosage was higher than 14%, the result was the opposite. The addition of recycled concrete powder and recycled brick powder was able to decrease the compressive strength of raw soil, except for 10% of recycled brick powder. Raw soil with recycled brick powder presented higher compressive strength than that of raw soil with recycled concrete powder. RBP could improve the freeze–thaw cycles’ resistance of specimens; however, RCP led to decreasing the resistance of freeze–thaw cycles. These research findings can provide reference to the recycling of construction waste.

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