scholarly journals Comparative Study Regarding the Compressive Strength of Different Composite Resins Used for Direct Restorations

2018 ◽  
Vol 55 (3) ◽  
pp. 447-453
Author(s):  
Irina Nica ◽  
Gianina Iovan ◽  
Simona Stoleriu ◽  
Cristina Angela Ghiorghe ◽  
Galina Pancu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Compressive Strain ◽  
Mechanical Tests ◽  
Ultimate Compressive Strength ◽  
Composite Resins ◽  
Compression Behavior ◽  
Post Hoc ◽  
Cylindrical Samples ◽  
Scanning Electron

The aim of this study was to evaluate and to compare the compression behavior under identical mechanical tests, of three different composite resins, by determining Young�s modulus for compression, ultimate compressive strength and ultimate compressive strain. The studied materials were: Filtek Z250 Universal Restorative, Filtek Z550 and Filtek Bulk Fill Posterior Restorative (3M ESPE, St. Paul, MN, USA). Fifteen cylindrical samples, having 6 mm in height and 5 mm in diameter, were made from each material, using plastic molds. The samples were subjected to quantitative analysis of the compression behavior after mechanical tests. The fractured fragments of the samples were subjected to qualitative surface evaluation by scanning electron microscopy. Results were statistically analyzed using one-way analysis of variance (ANOVA) with Tukey�s post hoc test. Filtek Z250 had the lowest value of Young�s modulus for compression and the results were statistically significant (p[0.05) when compared to Filtek Bulk Fill Posterior Restorative and Filtek Z550. There were no statistically significant differences between all three materials regarding ultimate compressive strength (p]0.05). The lowest value for ultimate compressive strain was recorded for Filtek Bulk Fill.

scholarly journals Evaluation of Mechanical Parameters at Compression Test for Different Restorative Composite Resins

2019 ◽  
Vol 56 (3) ◽  
pp. 592-595
Author(s):  
Andra Gamen ◽  
Gianina Iovan ◽  
Simona Stoleriu ◽  
Galina Pancu ◽  
Irina Nica ◽  
...  
Keyword(s):  
Compressive Strain ◽  
Mechanical Tests ◽  
Composite Resins ◽  
Mechanical Parameters ◽  
Compression Tests ◽  
Compression Behavior ◽  
Paired Samples ◽  
Kolmogorov Smirnov ◽  
Level Of Significance ◽  
Cylindrical Samples

The purpose of the present study was to evaluate the mechanical parameters at compression tests for two different restorative composite resins. The materials here under study were: Gradia Direct (GC Corporation, Tokyo, Japan) and Filtek Ultimate Universal Restorative, (3M ESPE, St. Paul, MN, USA). 30 cylindrical samples, 15 for each material, with a thickness of 6 mm and a diameter of 5 mm, were made. The compression behavior at mechanical tests for each sample was analyzed. One-Sample Kolmogorov-Smirnov Test followed by Paired Samples t-Test was used for statistical analysis and determining the level of significance. Gradia Direct had a lower value of Young�s modulus than Filtek Ultimate Universal Restorative, the results being statistically significant (p = 0.001 [ 0.05). The comparative evaluation of the compressive strength did not reveal statistically significant results between the two materials (p = 0.098 ] 0,05). Regarding the compressive strain the values were significantly lower for Filtek Ultimate Universal Restorative (p=0.000 [ 0.05). The microhybrid composite evaluated in the present study proved to have better mechanical properties than the nanofilled composite.

scholarly journals Effects on Mechanical Properties of Recycled PET in Cement-Based Composites

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Liliana Ávila Córdoba ◽  
Gonzalo Martínez-Barrera ◽  
Carlos Barrera Díaz ◽  
Fernando Ureña Nuñez ◽  
Alejandro Loza Yañez
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Compressive Strength ◽  
Compressive Strain ◽  
Young Modulus ◽  
Silica Sand ◽  
Chemical Compositions ◽  
Particle Sizes ◽  
Recycled Pet ◽  
Scanning Electron

Concretes consisting of portland cement (OPC), silica sand, gravel, water, and recycled PET particles were developed. Specimens without PET particles were prepared for comparison. Curing times, PET particle sizes, and aggregate concentrations were varied. The compressive strength, compressive strain at yield point, and Young modulus were determined. Morphological and chemical compositions of recycled PET particles were seen in a scanning electron microscopy. Results show that smaller PET particle sizes in lower concentrations generate improvements on compressive strength and strain, and Young’s modulus decreases when the size of PET particles used was increased.

scholarly journals Study on Strength Characteristics of Solidified Contaminated Soil under Freeze-Thaw Cycle Conditions

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Qiang Wang ◽  
Jinyang Cui
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Contaminated Soils ◽  
Unconfined Compressive Strength ◽  
Freeze Thaw ◽  
Thaw Cycle ◽  
Strength Tests ◽  
Freeze Thaw Cycle ◽  
Microcosmic Mechanism ◽  
Scanning Electron

Cement solidification/stabilization is a commonly used method for the remediation of contaminated soils. The stability characteristics of solidified/stabilized contaminated soils under freeze-thaw cycle are very important. A series of tests, which include unconfined compressive strength tests, freeze-thaw cycle tests, and scanning electron microscopy (SEM) tests, are performed to study the variation law of strength characteristics and microstructure. It aims at revealing the microcosmic mechanism of solidified/stabilized Pb2+ contaminated soils with cement under freeze-thaw cycle. The results show that the unconfined compressive strength of the contaminated soils significantly improved with the increase of the cement content. The unconfined compressive strength of stabilized contaminated soils first increases with the increase of times of freeze-thaw cycle, and after reaching the peak, it decreases with the increase of times of freeze-thaw cycle. The results of the scanning electron microscopy tests are consistent with those of the unconfined compressive strength tests. This paper also reveals the microcosmic mechanism of the changes in engineering of the stabilized contaminated soils under freeze-thaw cycle.

UTILIZATION OF FLY ASH AND CONCRETE RESIDUE IN THE PRODUCTION OF GEOPOLYMER BRICKS

2017 ◽  
Vol 12 (1) ◽  
pp. 63-77 ◽  
Author(s):  
Siriporn Sirikingkaew ◽  
Nuta Supakata
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Phase Composition ◽  
Fly Ash ◽  
Industrial Waste ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

This study presents the development of geopolymer bricks synthetized from industrial waste, including fly ash mixed with concrete residue containing aluminosilicate compound. The above two ingredients are mixed according to five ratios: 100:0, 95:5, 90:10, 85:15, and 80:20. The mixture's physico-mechanical properties, in terms of water absorption and the compressive strength of the geopolymer bricks, are investigated according to the TIS 168-2546 standard. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses are used to investigate the microstructure and the elemental and phase composition of the brick specimens. The results indicate that the combination of fly ash and concrete residue represents a suitable approach to brick production, as required by the TIS 168–2546 standard.

scholarly journals Valorization of Brick and Glass CDWs for the Development of Geopolymers Containing More Than 80% of Wastes

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 672
Author(s):  
Dimitris Kioupis ◽  
Aggeliki Skaropoulou ◽  
Sotirios Tsivilis ◽  
Glikeria Kakali
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Circular Economy ◽  
X Ray Diffraction ◽  
Glass Waste ◽  
X Ray ◽  
Optimum Synthesis ◽  
Synthesis Parameters ◽  
Construction And Demolition Wastes ◽  
Scanning Electron

One of the areas of priority in a circular economy, regarding waste management, regards the valorization of construction and demolition wastes (CDW). This study suggests the synthesis of geopolymeric binders based almost entirely on construction and demolition wastes. Ceramic waste was used as the aluminosilicate precursor of the geopolymer synthesis, while glass waste was applied in the preparation of the activation solution. A fractional experimental design defined the optimum synthesis parameters, based on compressive strength values. The final products were characterized by means of X-Ray Diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The glass waste was appropriately processed in order to prepare the activation solution for the geopolymerization of brick waste. In this work, CDW-based geopolymers were produced with a compressive strength in the range 10–44 MPa. The developed products contained 80–90 wt.% CDWs, depending on the method of activator preparation.

Influence of Foaming Agent on Properties of Red Mud Lightweight Baking-Free Brick

2014 ◽  
Vol 541-542 ◽  
pp. 388-391
Author(s):  
Long Ma ◽  
Guo Zhong Li
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Fly Ash ◽  
Flexural Strength ◽  
Red Mud ◽  
Micro Structure ◽  
Foaming Agent ◽  
Scanning Electron

Red mud lightweight baking-free brick was prepared by red mud, fly ash and cement, mixed with a certain amount of activator agent and foaming agent. The influence of foaming agent on properties of red mud lightweight baking-free brick was studied. The micro-structure of red mud lightweight baking-free brick was characterized by scanning electron microscopy (SEM). The results show that when the foaming agent content is 10ml, the sample with better performance obtained and the density is 423kg/m3, flexural strength is 0.49MPa and compressive strength is 1.87MPa.

Preparation, Microstructure and Properties of ZrO2 Gradient Porous Ceramics by Freeze-Casting Process

2015 ◽  
Vol 816 ◽  
pp. 226-230 ◽  
Author(s):  
Tao Tao Ai
Keyword(s):  
Electron Microscopy ◽  
Compressive Strength ◽  
Porous Structure ◽  
Cross Section ◽  
Lamellar Structure ◽  
Sintering Temperature ◽  
Casting Process ◽  
Porous Ceramics ◽  
Freeze Casting ◽  
Scanning Electron

The ZrO2gradient porous ceramics were prepared by a novel freeze-casting process. The porous structure of the ZrO2ceramics was investigated by scanning electron microscopy (SEM). And the porosity and compressive strength were also measured. Experimental results indicated that the porous structure of the specimens was remarkably affected by the sintering temperature. The dendritic pores were obtained after sintered at 1300 °C. The porosity and compressive strength of the specimen were 56.79% and 4.37 MPa, respectively. As the sintering temperature reached to 1500 °C, a lamellar structure was obtained on the cross-section of the specimen. Meanwhile, the porosity decreased to 26.77% and the compressive strength increased to 8.26 MPa. The ceramics can be divided subsequently into three distinctive zones along the solidification direction, i.e. lamellar zone, transition zone and cellular zone.

Study on Preparation and Properties of Vitrified Beads-Polystyrene Particles Insulation Mortar

2014 ◽  
Vol 538 ◽  
pp. 3-6
Author(s):  
Yu Peng Chen ◽  
Wen Hong Tao ◽  
Xing Hua Fu ◽  
Li Yuan Dong ◽  
Hai Tao Yu
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Compressive Strength ◽  
Dry Density ◽  
Function Mechanism ◽  
Testing Method ◽  
Hydrophobic Agent ◽  
Polypropylene Monofilament ◽  
Softening Coefficient ◽  
Scanning Electron

Orthogonal testing method was used to study the effects of polystyrene particles, hydrophobic agent, air-entraining agent, polypropylene monofilament fiber on dry density, compressive strength, water absorption and softening coefficient of composite insulation mortar. The optimal ratio was obtained as: 3% of the weight are polystyrene particles, 0.2% is hydrophobic agent, air-entraining agent counts for 0.4wt%，and polypropylene monofilament fiber 0.6%. The main performances of the mortar were recorded as: dry density was 228Kg/m3, 28 day compressive strength after conserved for 28 days was 0.54MPa, and thermal conductivity 0.0596W/(m•K). Microstructure of the composite insulation mortar was analyzed by SEM (scanning electron microscopy) and its function mechanism was studied preliminarily.

The Effect of Different Silica Compositions to the Properties of Silica Foam Fabricated Using Slurry Method

2017 ◽  
Vol 888 ◽  
pp. 121-125 ◽  
Author(s):  
Syazwani Baharom ◽  
Sufizar Ahmad ◽  
Muhamad Izranuddin Mohd Ramli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Compressive Strength ◽  
Polyethylene Glycol ◽  
Morphological Analysis ◽  
Strength Test ◽  
Distilled Water ◽  
Compressive Strength Test ◽  
Slurry Method ◽  
Scanning Electron

Silica foams with 50% – 70% porosity have been developed by mixing silica powder, polyethylene glycol (PEG) and carboxymethyl cellulose (CMC) into distilled water to make slurry. Polyurethane foam (PU) as the template is immersed into the slurry with 45 wt.%, 50 wt.% and 55 wt.%. of silica composition and finally sintered at 1100°C, 1200°C, 1300°C and 1400°C. Several tests which are morphological analysis, porosity and density test, and compressive strength test are compulsory to determine the physical and mechanical of the silica foam. The morphology of the foam has been observed using Scanning Electron Microscopy (SEM) and the result of pore size distribution is in the range of 255.91 μm to 489.14 μm. The porosity and density obtained from the porosity and density test was 50%-73.66% and 0.5499 g/cm³ up to 0.9757 g/cm³, respectively. Meanwhile, the compressive strength of sintered silica foam obtained is 0.01471 N/mm² up to 0.1467 N/mm².

scholarly journals Improvement of Mechanical and Rheological Properties of Natural Rubber for Anti-Vibration Applications

2017 ◽  
Vol 13 (2) ◽  
Author(s):  
Nabel K. Abd Ali ◽  
Malia. M. Farhan ◽  
Abbas S . Moosa
Keyword(s):  
Electron Microscopy ◽  
Natural Rubber ◽  
Mechanical Tests ◽  
Friction Resistance ◽  
Synthetic Rubber ◽  
Structure Morphology ◽  
Rheological Test ◽  
Sem Test ◽  
Master Batch ◽  
Scanning Electron

Abstract   This research aims to study and improve the passivating specifications of rubber resistant to  vibration. In this paper, seven different rubber recipes were prepared based on mixtures of natural rubber(NR)  as an essential part in addition to the synthetic rubber (IIR, BRcis, SBR, CR)with different rates. Mechanical tests such as tensile strength, hardness, friction, resistance to compression, fatigue and creep testing in addition to the rheological test were performed. Furthermore, scanning electron microscopy (SEM)test was used to examine the structure morphology of rubber. After studying and analyzing the results, we found that, recipe containing (BRcis) of 40% from the natural rubber has the best mechanical and physical specifications to be used in applications that require the presence of rubber, resistant to vibration. Keywords: Ant vibration behavior , Natural rubber, Synthetic rubber, master batch.

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