scholarly journals Supported ITZ Modification Efficiencies via Surface Coating Nanoparticles on Aggregate and its Influence on Properties

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3541 ◽  
Author(s):  
Kai Wu ◽  
Hao Han ◽  
Linglin Xu ◽  
Xiaojie Yang ◽  
Geert De Schutter
Keyword(s):  
Compressive Strength ◽  
Coating Thickness ◽  
Fine Particles ◽  
Chloride Penetration ◽  
Particle Packing ◽  
Coating Materials ◽  
Nano Sio2 ◽  
Backscattered Electron ◽  
Overall Performance ◽  
Materials Used

In order to modify the porous interfacial transition zone (ITZ) microstructure of concrete more efficiently, a method of coating aggregate surfaces by using several nanoparticles was evaluated in this study. The compressive strength, chloride penetration of sound, and pre-loading samples were assessed in relation to the type of coating materials used (slag, nano-CaCO3, and nano-SiO2) and the designed coating thickness (5, 10, and 15 μm). The ITZ microstructure was quantitatively determined via Backscattered electron (BSE) image analysis. Results showed that the overall performance of concrete is highly dependent on the coating materials and the designed coating thickness. Increasing the coating thickness of slag and nano-SiO2 could improve the chloride penetration resistance but decrease the compressive strength. Using nano-CaCO3 to coat the aggregate leads to a significant reduction in the properties of the so-prepared concrete. Though coating inert fine particles around aggregate could disturb the initial particle packing and modify the ITZ, it is not able to improve the overall concrete properties. Coating aggregate could determine the ITZ microstructure, especially within the region that is around 30 μm away from aggregate surface.

Durability of Sugar Cane Bagasse Ash (SCBA) Concrete towards Chloride Ion Penetration

2014 ◽  
Vol 567 ◽  
pp. 369-374 ◽  
Author(s):  
Nasir Shafiq ◽  
Asma Abd Elhsameed ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Weight Loss ◽  
Compressive Strength ◽  
Penetration Depth ◽  
Sugar Cane ◽  
Fine Particles ◽  
Strength Loss ◽  
Sugar Cane Bagasse ◽  
Chloride Penetration ◽  
Chloride Ingress ◽  
Sugar Cane Bagasse Ash

In this study, the effect of sugar cane bagasse ash (SCBA) on chloride penetration resistance of concrete was investigated. 100-mm side cubes were cast and cured in water for 28 days followed by six months curing in 4% NaCl solution. The resistance to chloride penetration was assessed by measuring the chloride penetration depth, weight loss, compressive strength loss and bond strength loss. Chloride penetration depth was measured using AgNO3–based method. It was obtained that inclusion of SCBA in concrete significantly reduced the chloride penetration depth, weight loss, compressive strength loss and bond loss that was attributed to the fine particles of SCBA that filled up the pores and prevented the chloride ingress in the concrete.

scholarly journals Evaluation of the Hydration Characteristics and Anti-Washout Resistance of Non-Dispersible Underwater Concrete with Nano-SiO2 and MgO

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1328
Author(s):  
In Kyu Jeon ◽  
Byeong Hun Woo ◽  
Dong Ho Yoo ◽  
Jae Suk Ryou ◽  
Hong Gi Kim
Keyword(s):  
Compressive Strength ◽  
Fine Particles ◽  
Setting Time ◽  
Peak Time ◽  
Nano Sio2 ◽  
Setting Times ◽  
Slump Flow ◽  
Compressive Strength Test ◽  
Underwater Concrete ◽  
Hydration Characteristics

In this paper, the effect of nano-SiO2 (NS) and MgO on the hydration characteristics and anti-washout resistance of non-dispersible underwater concrete (UWC) was evaluated. A slump flow test, a viscosity test, and setting time measurement were conducted to identify the impacts of NS and MgO on the rheological properties of UWC. The pH and turbidity were measured to investigate the anti-washout performance of UWC mixes. To analyze the hydration characteristics and mechanical properties, hydration heat analysis, a compressive strength test, and thermogravimetric analyses were conducted. The experimental results showed that the fine particles of NS and MgO reduced slump flow, increased viscosity, and enhanced the anti-washout resistance of UWC. In addition, both NS and MgO shortened the initial and final setting times, and the replacement of MgO specimens slightly prolonged the setting time. NS accelerated the peak time and increased the peak temperature, and MgO delayed the hydration process and reduced the temperature due to the formation of brucite. The compressive results showed that NS improved the compressive strength of the UWC, and MgO slightly decreased the strength. The addition of NS also resulted in the formation of extra C–S–H, and the replacement of MgO caused the generation of a hydrotalcite phase.

scholarly journals Experimental Analysis of the Mechanical Properties and Resistivity of Tectonic Coal Samples with Different Particle Sizes

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2303
Author(s):  
Congyu Zhong ◽  
Liwen Cao ◽  
Jishi Geng ◽  
Zhihao Jiang ◽  
Shuai Zhang
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Uniaxial Compressive Strength ◽  
Coalbed Methane ◽  
Coal Sample ◽  
Fine Particles ◽  
Particle Sizes ◽  
Tectonic Coal

Because of its weak cementation and abundant pores and cracks, it is difficult to obtain suitable samples of tectonic coal to test its mechanical properties. Therefore, the research and development of coalbed methane drilling and mining technology are restricted. In this study, tectonic coal samples are remodeled with different particle sizes to test the mechanical parameters and loading resistivity. The research results show that the particle size and gradation of tectonic coal significantly impact its uniaxial compressive strength and elastic modulus and affect changes in resistivity. As the converted particle size increases, the uniaxial compressive strength and elastic modulus decrease first and then tend to remain unchanged. The strength of the single-particle gradation coal sample decreases from 0.867 to 0.433 MPa and the elastic modulus decreases from 59.28 to 41.63 MPa with increasing particle size. The change in resistivity of the coal sample increases with increasing particle size, and the degree of resistivity variation decreases during the coal sample failure stage. In composite-particle gradation, the proportion of fine particles in the tectonic coal sample increases from 33% to 80%. Its strength and elastic modulus increase from 0.996 to 1.31 MPa and 83.96 to 125.4 MPa, respectively, and the resistivity change degree decreases. The proportion of medium particles or coarse particles increases, and the sample strength, elastic modulus, and resistivity changes all decrease.

scholarly journals Assessment of dissolution profile of Pantoprazole tablets available in Bangladesh

2012 ◽  
Vol 4 (2) ◽  
pp. 58-62
Author(s):  
Aparajita Malakar ◽  
Bishwajit Bokshi ◽  
Utpal Kumar Karmakar
Keyword(s):  
Dissolution Rate ◽  
Solid Dispersion ◽  
Water Soluble ◽  
Dissolution Profile ◽  
Coating Materials ◽  
Volatile Solvents ◽  
Kneading Method ◽  
Enhanced Solubility ◽  
Materials Used ◽  
Liquisolid Compacts

The aim of the present study was to increase the solubility of a poorly water soluble BCS class II drug, valsartan. Liquisolid technology and solid dispersion by kneading method were techniques used to improve the solubility of the drug by using non-volatile solvents and some hydrophilic carriers. Liquisolid compacts were prepared by dissolving the drug in suitable non volatile solvents. The various non volatile solvents used were PG, PEG, and glycerine. The carrier coating materials play an important role in improving the solubility of the drug. The dissolution rate of the drug was increased by using propylene glycol as non-volatile solvent at 20:1 ratio of carrier to coating material. Solid dispersion by kneading method were another attempt to improve solubility the various carrier materials used were PVP K 30, PEG 6000 and mannitol, these carriers are used in various ratios to improve its solubility. The dissolution rate of drug using solid dispersion kneading method with mannitol was increased at 1:3 ratio. The DSC and FTIR studies revealed no drug excipients interactions, whereas XRD revealed the reduced crystalinity of drug, which showed enhanced solubility. From the results it was concluded that the liquisolid compacts enhanced the solubility of valsartan in comparison to traditional solid dispersion method.DOI: http://dx.doi.org/10.3329/sjps.v4i2.10441  S. J. Pharm. Sci. 4(2) 2011: 58-62

Physical Properties of Cement Mortar Containing Waste Ash

2015 ◽  
Vol 804 ◽  
pp. 129-132
Author(s):  
Sumrerng Rukzon ◽  
Prinya Chindaprasirt
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Cement Mortar ◽  
Ash Content ◽  
Water Requirement ◽  
Test Results ◽  
Pozzolanic Material ◽  
Materials Used

This research studies the potential for using waste ash from industrial and agricultural by-products as a pozzolanic material. Classified fly ash (FA) and ground rice husk ash (RA) were the materials used. Water requirement, compressive strength and porosity of cement mortar were investigated. Test results indicated that FA and RA (waste ash) have a high potential to be used as a good pozzolanic material. The water requirement of mortar mix decreases with the increases in fly ash content. For ground rice husk ash (RA), the water requirement of mortar mix increases with the increases in rice husk ash content. In addition, the reduction in porosity was associated with the increase in compressive strength.

scholarly journals Study of the Electrical Properties of Aluminate Cement Adhesives for Porcelain Insulators

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2232
Author(s):  
Huiwen Wan ◽  
Zhangyin Hu ◽  
Gang Liu ◽  
Jiadong Xiao
Keyword(s):  
Compressive Strength ◽  
Electrical Properties ◽  
Silica Fume ◽  
Drying Time ◽  
Pore Connectivity ◽  
Cement Based Materials ◽  
Porcelain Insulators ◽  
Materials Used ◽  
The Cost ◽  
Aluminate Cement

Electrical properties are one of the essential parameters of cement-based materials used in suspension porcelain insulators. This paper studied the electrical properties of aluminate cement adhesives (ACA) containing silica fume (SF), as well as their compressive strength and porosity. The results indicated that the addition of silica fume improved the resistivity of ACA under a saturated state (relative humidity is 50%). This was mainly attributed to the decrease of the ACA’s pore connectivity due to the SF’s filling effect. However, the early compressive strength of ACA was slightly reduced by the addition of SF. Under an unsaturated state, the ACA’s resistivity without the SF gradually exceeded that with the SF at the extension of drying time. The nuclear magnetic resonance (NMR) results indicated that the addition of SF content increased the ACA’s porosity; for the tiny pores especially, (the size less than 25 nm), this increased by 3.4%. Meanwhile, the addition of SF increased the tortuosity of the ACA’s conductive channels, which could improve its resistivity. Therefore, SF is recommended to be used in cement-based adhesives on insulators to lower the cost and improve the resistivity.

Wear of Coated Cutting Tool Based on AdvantEdge

2014 ◽  
Vol 551 ◽  
pp. 221-227
Author(s):  
Zhi Qiang Zhang ◽  
Tie Qiang Gang ◽  
Yi Kai Yi
Keyword(s):  
Wear Rate ◽  
Coating Thickness ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Simulation Software ◽  
Machining Process ◽  
Sliding Velocity ◽  
Coating Materials ◽  
Element Simulation ◽  
Coated Tool

In this paper, based on finite element simulation software AdvantEdge, the effects of different coating materials and thickness on the wear of cutting tools during the machining process have been studied. For the tools with coating materials of TiAlN, Al2O3, TiN, TiC, we can calculate the wear rate according to the Usui mathematical model of tool wear, and then consider thickness factor of TiC coating. Because of the lowest thermal conductivity, the workpiece cut by TiC coated tool will soften first and more over cutting time, it result in the lowest wear rate. And with the increase of coating thickness, the effect of "thermal barrier" is more obvious for the relatively thicker coating tool, but the relative sliding velocity between the chip and tool is increasing meanwhile, so a suitable coating thickness is necessary.

scholarly journals Mechanical Properties of High Strength Concrete Containing Nano SiO2 Made from Rice Husk Ash in Southern Vietnam

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 932
Author(s):  
Huu-Bang Tran ◽  
Van-Bach Le ◽  
Vu To-Anh Phan
Keyword(s):  
Compressive Strength ◽  
Rice Husk ◽  
High Strength Concrete ◽  
Rice Husk Ash ◽  
Chloride Ion ◽  
High Strength ◽  
Ion Permeability ◽  
Strength Concrete ◽  
Nano Sio2 ◽  
Southern Vietnam

This paper presents the experimental results of the production of Nano-SiO2 (NS) from rice husk ash (RHA) and the engineering properties of High Strength Concrete (HSC) containing various NS contents. Firstly, the mesoporous silica nanoparticles were effectively modulated from RHA using NaOH solution, and subsequently precipitated with HCl solution until the pH value reached 3. The optimum synthesis for the manufacture of SiO2 nanoparticles in the weight ratio of RHA/NaOH was 1:2.4, and the product was calcined at 550 °C for 2 h. The EDX, XRD, SEM, TEM, FT-IR, and BET techniques were used to characterize the NS products. Results revealed that the characteristics of the obtained NS were satisfactory for civil engineering materials. Secondly, the HSC was manufactured with the aforementioned NS contents. NS particles were added to HSC at various replacements of 0, 0.5, 1.0, 1.5, 2.0, and 2.5% by the mass of the binder. The water-to-binder ratio was remained at 0.3 for all mixes. The specimens were cured for 3, 7, 28, 25 days under 25 ± 2 °C and a relative humidity of 95% before testing compressive and flexural strengths. Chloride ion permeability was investigated at 28 and 56 days. Results indicated that the addition of NS dramatically enhanced compressive strength, flexural strength, chloride ion resistance, and reduced chloride ion permeability compared to control concrete. The optimal NS content was found at 1.5%, which yielded the highest strength and lowest chloride ion permeability. Next, the development of flexural and compressive strengths with an age curing of 3–28 days can be analytically described by a logarithmic equation with R2 ≥ 0.74. The ACI code was used, and the compressive strength at t-day was determined based on 28 days with R2 ≥ 0.95. The study is expected to solve the redundancy of waste RHA in southern Vietnam by making RHA a helpful additive when producing high-strength concrete and contributing meaningfully to a sustainable environment.

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