scholarly journals The Analysis of the Influence of the Polystyrene Patterns Shaping Parameters on the Resistance Properties

2012 ◽  
Vol 12 (2) ◽  
pp. 227-234
Author(s):  
T. Pacyniak ◽  
K. Buczkowska ◽  
W. Bogus
Keyword(s):  
Flexural Strength ◽  
Strength Properties ◽  
Sintering Process ◽  
Research Results ◽  
Foam Plastics

The Analysis of the Influence of the Polystyrene Patterns Shaping Parameters on the Resistance Properties This work presents the technology of making foam plastics patterns used in casting as well as the final shaping stand. The analysis of the sintering process was carried out aiming at determining the influence of the pressure and the time of sintering on the flexural strength properties. The analysis of the research results confirmed that when the sintering pressure grows to the value of Pa =1,7 bar the flexural strength also increases, when the pressure value is higher than that, the degradation of the material takes place and the strength properties decrease.

scholarly journals Deformation Behavior and Fracture Patterns of Laminated PEEK- and PI-Based Composites with Various Carbon-Fiber Reinforcement

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2268
Author(s):  
Pavel V Kosmachev ◽  
Vladislav O Alexenko ◽  
Svetlana A Bochkareva ◽  
Sergey V Panin
Keyword(s):  
Carbon Fiber ◽  
Flexural Strength ◽  
Laminated Composites ◽  
Flexural Modulus ◽  
Strength Properties ◽  
Fe Model ◽  
Carbon Fabric ◽  
Model Framework ◽  
Order Of Magnitude ◽  
Stress States

Laminated composites based on polyetheretherketone (PEEK) and polyimide (PI) matrices were fabricated by hot compression. Reinforcing materials (unidirectional carbon-fiber (CF) tapes or carbon fabric) and their layout patterns were varied. Stress–strain diagrams after three-point flexural tests were analyzed, and both lateral faces of the fractured specimens and fractured surfaces (obtained by optical and scanning electron microscopy, respectively) were studied. It was shown that the laminated composites possessed the maximum mechanical properties (flexural elastic modulus and strength) in the case of the unidirectional CF (0°/0°) layout. These composites were also not subjected to catastrophic failure during the tests. The PEEK-based composites showed twice the flexural strength of the PI-based ones (0.4 and 0.2 GPa, respectively), while the flexural modulus was four times higher (60 and 15 GPa, correspondently). The reason was associated with different melt flowability of the used polymer matrices and varied inter- (intra)layer adhesion levels. The effect of adhesion was additionally studied by computer simulation using a developed two-dimensional FE-model. It considered initial defects between the binder and CF, as well as subsequent delamination and failure under loads. Based on the developed FE-model, the influence of defects and delamination on the strength properties of the composites was shown at different stress states, and the corresponding quantitative estimates were reported. Moreover, another model was developed to determine the three-point flexural properties of the composites reinforced with CF and carbon fabric, taking into account different fiber layouts. It was shown within this model framework that the flexural strength of the studied composites could be increased by an order of magnitude by enhancing the adhesion level (considered through the contact area between CF and the binder).

scholarly journals The effect of curing conditions on the mechanical properties of SIFCON

2021 ◽  
Vol 20 (1) ◽  
pp. 37-51
Author(s):  
Kubilay Akçaözoğlu ◽  
◽  
Adem Kıllı ◽  
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Steel Fiber ◽  
Impact Resistance ◽  
Strength Properties ◽  
Fiber Reinforced Concrete ◽  
Curing Conditions ◽  
Accelerated Curing ◽  
Aspect Ratios ◽  
Curing Method

In this study, the effect of curing conditions on the mechanical properties of slurry infiltrated fiber reinforced concrete (SIFCON) was investigated. For this purpose, SIFCON samples containing 4% and 8% steel fiber with two different aspect ratios were produced. The samples were subjected to three different curing types, namely standard, dry and accelerated curing methods. Ultrasonic wave velocity, flexural strength, fracture toughness, compressive strength, impact resistance and capillary water absorption tests were performed on the samples. The highest flexural strength was found to be achieved in the samples with an aspect ratio of 55 and a content of 8% steel fiber. The most suitable curing method was determined as the standard curing method and the best flexural strength was achieved at the rate of 8%. According to the test results, the best strength properties were achieved in the samples exposed to the standard curing method. In addition, the samples exposed to the accelerated curing method showed satisfactory values. The accelerated curing method can be used as an alternative in SIFCON production especially in applications requiring mass production.

scholarly journals Rheology, fresh and hardened properties of self-consolidating concrete utilizing metal and PVA polymer fibers

2021 ◽  
Author(s):  
Moustafa M Sammour
Keyword(s):  
Flexural Strength ◽  
Fracture Energy ◽  
Strength Properties ◽  
Fiber Reinforced Concrete ◽  
Fiber Types ◽  
Fiber Reinforced ◽  
Segregation Index ◽  
Self Consolidating Concrete ◽  
Funnel Flow ◽  
Energy Absorbing

Fiber reinforced self-consolidating concrete (FRSCC) has a tremendous potential to be used in construction industry as it combines the advantagees of both self-consolidating concrete (SCC) and fiber reinforced concrete (FRC). 18 concrete mixtures were developed by incorporating differenct volumes (0 to 0.3) of polyvinyl alchohol (PVA) and metallic fibers. Fresh, rheological, mechanical and durability (in terms of chloride penetration resistance) properties of all FRSCC mixtures were evaluated. The influences of fiber types/size/ dosages and fiber combination (used in hybrid mixes) on fresh (slump flow, L-box passing ability, V-funnel flow time and segregation index), rheological (plastic viscosity and yield stress) and hardened (fracture energy and compressive/flexural/splitting tensile strength) properties were critically analyzed to examine the relationships among various properties as well as to suggest suitable FRSCC mixtures. The fibers (especially metallic ones) wre more effective in increasing the fracture energy of FRSCC than compressive/splitting tensile/flexural strength. A fracture energy gain of about 730% was observed (which is substantial) compared to 10% of compressive strength, 39% of splitting tensil strength and 124% of flexural strength. The improved strength and fracture energy of FRSCC mixtures can significantly reduce the amount of tensile reinforcement and subsantially increase the energy absorbing capacity of concrete structures.

scholarly journals Steel scrap added roller compacted concrete

2019 ◽  
Vol 10 (1) ◽  
pp. 7
Author(s):  
Kemal Armagan ◽  
Sadık Alper Yıldızel ◽  
Yusuf Arslan
Keyword(s):  
Flexural Strength ◽  
Steel Slag ◽  
High Volume ◽  
Strength Properties ◽  
Promising Material ◽  
Steel Scrap ◽  
Freeze Thaw ◽  
Roller Compacted Concrete ◽  
Local Roads ◽  
Mechanical Performances

The purpose of this paper is to investigate the benefits of using steel slag as an additive in Roller Compacted Concrete (RCC) which is a promising material can be used in streets, local roads, residential streets, high-volume roads, industrial access roads, airports...etc. The mechanical performances of steel scrap added reinforced cementitious composites produced with an industrial punch scrap. In specimen mixtures two types of scraps with diameters of 5 mm and 7 mm were used. The additive was mixed with 1%, 1.5% and 2% ratios by weight. Due to the results of the study, it was obtained that flexural strength properties of the specimens have increased up to 11%. In addition, freeze thaw effect of the specimens was investigated and found that 2% percent of scrap usage was given the best results.

Durability of Cement Based Mortars Containing Crystalline Additives

2018 ◽  
Vol 382 ◽  
pp. 246-253 ◽  
Author(s):  
Nikol Žižková ◽  
Lenka Nevřivová ◽  
Matěj Lédl
Keyword(s):  
Flexural Strength ◽  
Degradation Process ◽  
Secondary Crystallization ◽  
Curing Conditions ◽  
Research Results ◽  
New Information ◽  
Cement Mortars

The paper focuses on the study of the durability of cement mortars made with secondary crystallization additives. It investigates the influence of the crystalline additives on the degradation process of cement mortars exposed to gaseous CO2and freezing cycles. The specimens with were tested for compressive and flexural strength at the following ages and after being treated by the following curing techniques: 28 days, 180 days and 25 freezing cycles, 28 days and 180 days in gaseous CO2. In order to explain the obtained results and to gain new information about the microstructure of the cement mortars being studied, the SEM sampling and RDA analysis were performed. The research results confirm an improvement in the resistance of cement based mortars using crystalline additives against cyclic freezing as well as gaseous CO2. An important parameter that influences the effectiveness of the crystalline additive is the curing conditions during the first 28 days of ageing.

scholarly journals Influence of Linseed Oil Varnish Admixture on Glauconite Clay Mortar Properties

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5487
Author(s):  
Przemysław Brzyski ◽  
Magdalena Grudzińska
Keyword(s):  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Strength ◽  
Water Resistance ◽  
Linseed Oil ◽  
Sorption Properties ◽  
Vapor Permeability ◽  
Research Results ◽  
Positive Effect

Raw clay is used nowadays in construction as a component of mortars and plasters and as a binder in composites based on straw or shives. It is a material with good sorption properties and vapor permeability, but it is susceptible to shrinkage, is not resistant to water, and also is characterized by low mechanical strength, which makes it impossible to be used, for example, in external plasters. Various additives and admixtures are used to improve selected properties of clay mortars. The article presents the research results and assessment of the effect of glauconite clay mortar modification with an admixture of linseed oil varnish on selected properties. Admixtures in the amounts of 1%, 2%, and 3% in relation to clay weight were used. Flexural and compressive strength, water resistance, shrinkage, drying capacity, density, and porosity of mortar, were tested. The admixture of linseed oil varnish in the amounts used in the investigation had a positive effect on some of the tested properties; regardless of the quantity of the admixture, the modified mortars had better parameters concerning flexural strength, shrinkage reduction, and water resistance than the reference mortar, without admixture.

Influence of B2O3 on Dielectric, Mechanical, and Thermal Properties of MgO-Al2O3-SiO2 Glass-Ceramics

2019 ◽  
Vol 821 ◽  
pp. 435-439
Author(s):  
Bo Li ◽  
Ke Jing ◽  
Hai Bo Bian
Keyword(s):  
Activation Energy ◽  
Thermal Expansion ◽  
Thermal Properties ◽  
Low Temperature ◽  
Flexural Strength ◽  
Glass Ceramic ◽  
Glass Ceramics ◽  
Mechanical And Thermal Properties ◽  
Sintering Process ◽  
Low Thermal Expansion

Low temperature sintered MgO-Al2O3-SiO2 glass-ceramic with high mechanical and low thermal expansion was prepared for package. The remarkable influence of B2O3 addition on the electrical, mechanical, and thermal properties was fully investigated. A small amount of B2O3 promoted the sintering process and improved the densification of MAS. The kinetics via Kissinger method indicated that an appropriate B2O3 content decreased the activation energy and helped the occurrence of crystallization. Due to the increase of crystallinity and indialite phase, B2O3 addition significantly enhanced flexural strength and Young’s modulus. MAS doped with 3wt% B2O3 can be sintered at 900 °C and obtained good properties: σ = 229 MPa, φ = 86 GPa, α = 1.66×10-6 /°C, εr = 5.29, and tanδ = 5.9×10-4.

Highly Elastic Corrugated Cardboard and its Experimental Study on Strength Properties

2013 ◽  
Vol 469 ◽  
pp. 217-220
Author(s):  
Chun Ying Fu ◽  
Dong Sheng Jiang
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Strength Properties ◽  
Production Methods ◽  
Research Results ◽  
Actual Production ◽  
Corrugated Cardboard

In order to overcome weaknesses of the limited strength of the traditional corrugated cardboard, and the corrugated cardboard with alternative high and low corrugated sandwich cores was developed by someone, named highly elastic corrugated cardboard. The highly elastic corrugated cardboard has excellent rebound properties of cushioning . On the existing research results, according to Wang Dong-mei development of its production methods, the author can product highly elastic corrugated cardboard in the laboratory in order to study its Strength properties. These experimental data provide a basis for actual production.

Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units

2007 ◽  
Vol 8 (2) ◽  
pp. 35-42 ◽  
Author(s):  
Fabrício Aulo Ogliari ◽  
Ulisses Bastos Campregher ◽  
Susana Maria Werner Samuel ◽  
Carmen Beatriz Borges Fortes ◽  
Alberth David Correa Medina ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Second Generation ◽  
Light Emitting Diode ◽  
Strength Properties ◽  
Knoop Hardness ◽  
Curing Time ◽  
Light Emitting ◽  
Led Light ◽  
Three Samples ◽  
Light Curing

Abstract Aim The purpose of this study was to evaluate the effectiveness of three commercially available light emitting diode (LED) light curing units (LCU) (Elipar FreeLight - 3M ESPE; UltraLume LED2 - Ultradent; and Single V - BioArt) for polymerizing Z250-A3 composite (3M ESPE) using Knoop hardness, polymerization depth, and flexural strength properties. Methods and Materials The XL 2500 (3M ESPE) LCU, which is a conventional halogen unit, was used as a control. In all cases the curing time was 20 seconds. Hardness was determined 24 hours after composite cure for 10 samples of 8 mm diameter and 2 mm height for each LCU tested. Samples were stored dry in a lightproof container prior to testing. The depth of cure of the composite was measured immediately after composite polymerization for each LCU using three samples 4 mm in diameter and 6 mm in height. Flexural strength was determined for five samples 24 hours after immersion in distilled water at 37°C. Each sample measured 25 mm in length, 2 mm in width, and 2 mm in height for each LCU tested. Conclusion The results were treated statistically for comparison of the LCUs. In all cases the results obtained by LED LCUs were not different or were higher than a conventional halogen LCU. Clinical Significance Second generation LED LCUs were as effective as/or more effective than a halogen LCU for polymerization of the used composite. The present study shows second generation LEDs have the potential to replace halogen LCUs. Citation Campregher UB, Samuel SMW, Fortes CBB, Medina ADC, Collares FMC, Ogliari FA. Effectiveness of Second-generation Light-emitting Diode (LED) Light Curing Units. J Contemp Dent Pract 2007 February;(8)2:035-042.

Biaxial Flexural Strength and Estimation of Size on the Strength Properties of FRP Composites

1990 ◽  
Vol 40 (2) ◽  
pp. 171-181
Author(s):  
M. N. Saraf ◽  
R. K. Gupta ◽  
B. Vishwanath ◽  
A. D. Manohar
Keyword(s):  
Flexural Strength ◽  
Strength Properties ◽  
Frp Composites ◽  
Biaxial Flexural Strength
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