Experimental Performance of Polyester-Fiber-Based Soil Geogrids against Reflective Cracks

2021 ◽  
pp. 036119812110275
Author(s):  
Burak Evirgen ◽  
Baris Buyuk ◽  
Gizem Tugce Cil ◽  
Tonguc Deger
Keyword(s):  
Cyclic Loading ◽  
Bending Strength ◽  
Fatigue Loading ◽  
Climatic Conditions ◽  
Polyester Fiber ◽  
Elastic Behavior ◽  
Experimental Performance ◽  
Three Point Bending ◽  
Full Capacity ◽  
Dynamic Fatigue

Road pavements may be subjected to deterioration problems caused by excessive traffic loads, thousands of load repetitions, environmental and climatic conditions, freeze-thaw effects, and insufficient design of mixtures. The formation of reflective cracks is the most common structural problem that occurs on a road’s superstructure over time. Special applications requiring expensive geosynthetics, such as glass-fiber-based geogrids (GG) or carbon-fiber-based geogrids, are generally used to solve this problem. Therefore, in this study, the utility of polyester-fiber-based soil geogrid (PG) is investigated as an alternative solution in relation to experimental performance analysis. Three-point bending tests are realized to custom-engineered hot mix asphalt plate specimens, with and without geogrids, under full-capacity static loading, cyclic loading, and dynamic fatigue loading conditions. Although the same bending strength levels are seen for plate specimens, including GG and PG reinforcements with a 100 kN/m tensile strength, PG-containing specimens show a 42% greater performance in the case of cyclic loading. Moreover, PG-reinforced plates have greater elastic behavior than GG plates, up to 49.4% within a dynamic fatigue test at the end of 15,000 cycles. As a result, it is shown that reflective cracks can be more effectively delayed by the use of soil PGs, rather than GGs, in relation to overall performance and service life.

Effects of hostile solutions on the static and dynamic behavior of carbon/epoxy composites

2021 ◽  
pp. 002199832110200
Author(s):  
H Ersen Balcıoğlu ◽  
Raif Sakin ◽  
Halit Gün
Keyword(s):  
Bending Strength ◽  
Laminated Composites ◽  
Fatigue Behavior ◽  
Laminated Composite ◽  
Test Sample ◽  
Solution Concentration ◽  
Static Stability ◽  
Three Point Bending ◽  
Sem Image ◽  
Solution Type

Fiber-reinforced laminated composite is often used in harsh environments that may affect their static stability and long-term durability as well as residual strength. In this study, the effect of heavy chemical environments such as acid and alkaline and retaining time for these environments on flexural strength and flexural fatigue behavior of carbon/epoxy laminated composites were investigated. In this context, carbon/epoxy was retained into an acidic and alkaline solution having 5%, 15%, and 25% concentration by weight for 1–4 months. Fatigue behavior of carbon/epoxy was determined under dynamic flexural load, which corresponds to 80%, 70%, 60%, 50%, and 40% of static three-point bending strength of the test sample. SEM image of damaged specimens was taken to describe the failure mechanism of damage which occurs after fatigue. Also, to better understand environmental condition on the fatigue life, results were compared with results of carbon/epoxy laminated composites, which were not retained into any environments (unretained). The test results showed that the solution type, solution concentration, and retaining time caused noticeable changes in the static and dynamic strengths of carbon/epoxy laminated composites.

scholarly journals Chlorine-Functional Silsesquioxanes (POSS-Cl) as Effective Flame Retardants and Reinforcing Additives for Rigid Polyurethane Foams

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3979
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Karolina Miedzińska ◽  
Krzysztof Strzelec
Keyword(s):  
Flame Retardants ◽  
Elevated Temperatures ◽  
Bending Strength ◽  
Reaction System ◽  
Fire Retardant ◽  
Polyurethane Foams ◽  
Polymerization Reaction ◽  
Three Point Bending ◽  
One Step

The subject of the research was the production of silsesquioxane modified rigid polyurethane (PUR) foams (POSS-Cl) with chlorine functional groups (chlorobenzyl, chloropropyl, chlorobenzylethyl) characterized by reduced flammability. The foams were prepared in a one-step additive polymerization reaction of isocyanates with polyols, and the POSS modifier was added to the reaction system in an amount of 2 wt.% polyol. The influence of POSS was analyzed by performing a series of tests, such as determination of the kinetics of foam growth, determination of apparent density, and structure analysis. Compressive strength, three-point bending strength, hardness, and shape stability at reduced and elevated temperatures were tested, and the hydrophobicity of the surface was determined. The most important measurement was the determination of the thermal stability (TGA) and the flammability of the modified systems using a cone calorimeter. The obtained results, after comparing with the results for unmodified foam, showed a large influence of POSS modifiers on the functional properties, especially thermal and fire-retardant, of the obtained PUR-POSS-Cl systems.

scholarly journals Monitoring the fatigue crack on the test specimen during the cyclic loading

2018 ◽  
Vol 157 ◽  
pp. 01016 ◽  
Author(s):  
Milan Sapieta ◽  
Peter Šulka ◽  
Martin Svoboda
Keyword(s):  
Fatigue Crack ◽  
Cyclic Loading ◽  
Test Specimen ◽  
Infrared Camera ◽  
Measurement Time ◽  
Three Point Bending ◽  
Whole Process

The main purpose of this paper is monitoring propagation of plastic area of fatigue crack. There were made notch on specimens and they were cyclically loaded with three-point bending. The record was evaluated after a certain number of loading cycles. The loading force is still constant throughout the measurement time for all specimens. The whole process was recorded using an infrared camera.

scholarly journals Analysis of Damage Evolution in Concrete under Fatigue Loading by Acoustic Emission and Ultrasonic Testing

Materials ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 341
Author(s):  
Marc Thiele ◽  
Stephan Pirskawetz
Keyword(s):  
Acoustic Emission ◽  
Elastic Modulus ◽  
Cyclic Loading ◽  
Fatigue Damage ◽  
Fatigue Loading ◽  
Measurement Methods ◽  
Material Structure ◽  
Fatigue Process ◽  
Acoustic Methods ◽  
Normal Strength

The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.

scholarly journals Knitted Meshes for Reinforcing Building Composites

2019 ◽  
Vol 27 (4(136)) ◽  
pp. 102-111
Author(s):  
Zbigniew Mikołajczyk ◽  
Katarzyna Pieklak ◽  
Aleksandra Roszak
Keyword(s):  
Concrete Beam ◽  
Bending Strength ◽  
Relative Elongation ◽  
Testing Machine ◽  
Strength Analysis ◽  
Knitted Fabrics ◽  
Three Point Bending ◽  
Concrete Mass ◽  
Frp Composites ◽  
Technical Textiles

Modern technical textiles, including knitted fabrics, are widely used in the construction industry. Regarding textiles in concrete reinforcement, methods based on shredded fibres, meshes, reinforcing mats, woven textiles and knitted DOStapes are frequently used as underlays of concrete constructions. Textiles are also used in the reinforcement of fibrous FRP composites. The research presented focused on producing composites made of MapeiMapefill concrete mass with reinforcement in the form of three variants of knitted meshes made of 228 tex polyamide threads, polypropylene threads of 6.3 tex and 203 tex glass threads, as well as identification of their mechanical properties. The mesh variant made of glass fibre is especially noteworthy, as its strength is more than three times higher than that of polyamide meshes. At the same time, a very small relative elongation of 3% is observed for this variant of knitted fabric, which is a desired property regarding the comparatively low stretching extension of concrete. In the process of making the composites, the adhesion of the concrete mass to the surface of the threads was analyzed. For this purpose, a "Sopro HE449" type agent was used. Composite beams were subjected to a three-point bending strength analysis on a testing machine. The results of strength measurements of the composites obtained prove that those with glass fibres demonstrate a threefold increase in strength compared to the original concrete beam.

CORRELATION DEPENDENCES OF THE BENDING STRENGTH OF POLYMER COMPOSITE MATERIALS MODIFIED IN A MICROWAVE ELECTROMAGNETIC FIELD ON THE MOISTURE CONTENT DURING EXPOSURE IN FULL-SCALE CONDITIONS

2021 ◽  
pp. 3-9
Author(s):  
I. V. Zlobina ◽  
I. S. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Moisture Content ◽  
Bending Strength ◽  
Climatic Factors ◽  
Experimental Studies ◽  
Three Point Bending ◽  
Treated Carbon ◽  
Control Samples

Experimental studies of the influence of external climatic factors, taking into account exposure, on the change in the bending strength of control and microwave – treated carbon and fiberglass samples in the cured state were performed. An increase in the limit stresses of three – point bending of experimental carbon fiber samples compared to the control ones was found by 7…12 %, and fiberglassby 4…7 %. It is shown that with an increase in exposure to 14 months, the strength of control samples of carbon and fiberglass decreases by an average of 10 %. At the same time, the strength of the prototypes is reduced only by 4.4 %. With an increase in the moisture content of both control and experimental samples, a decrease in their strength is observed. In this case, the linear correlation is average (from– 0.44 to – 0.615). It is established that for experimental samples, the influence of the amount of absorbed moisture on the strength is manifested to a much lesser extent. For carbon fiber, the reduction is 16.6 %, for fiberglass – 12 %.

THE INFLUENCE OF CLIMATIC FACTORS ON RESIDUAL STRESSES IN NANOMODIFIED CYANATE ESTER-BASED CFRP

2021 ◽  
pp. 104-112
Author(s):  
V.O. Startsev ◽  
◽  
E.V. Nikolaev ◽  
A.M. Vardanyan ◽  
A.A. Nechaev ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Residual Stresses ◽  
Bending Strength ◽  
Climatic Factors ◽  
Linear Thermal Expansion ◽  
Cold Climate ◽  
Cyanate Ester ◽  
Three Point Bending ◽  
Reinforced Plastic ◽  
Climatic Testing

The residual stresses in carbon fiber reinforced plastic (CFRP), based on VTkU-2.200 carbon fiber and VSC-14 cyanate ester resin, modified by nanoscale additives (astralen) were studied. Natural exposure was performed in a moderately cold climate. The influence of nanoadditives on mechanical and physical CFRP’s properties after 9 months of climatic testing was studied using the following properties: three-point bending strength, compression strength, coefficient of linear thermal expansion, glass transition temperature and residual stresses parameters. The increase of residual stresses after climatic testing was revealed.

Stiffness Degradation of Digital Polypropylene Under Fatigue Loading: Investigations via 3-Dimensional Polyjet Printed Coupons

2020 ◽  
Author(s):  
Ravi Pratap Singh Tomar ◽  
Furkan I. Ulu ◽  
Ajit Kelkar ◽  
Ram V. Mohan
Keyword(s):  
Experimental Data ◽  
Regression Analysis ◽  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Loading ◽  
Stiffness Degradation ◽  
Damage State ◽  
3 Dimensional ◽  
Accumulated Damage ◽  
Polyjet Printing

Abstract The utilization of additively manufactured parts is gaining popularity in functional applications. Polymer-based additive manufacturing (AM) parts are utilized in a variety of engineering applications for automotive, aerospace, and energy. AM printed parts are however newer class of materials, and structural performance of these materials is not fully understood completely, and very limited exists currently on precisely performance of Polyjet printed parts and associated digital materials under fatigue loading. This paper investigates the stiffness degradation under tension-tension fatigue loading of digital polypropylene using homogenous 3-Dimensional test coupons formed using PolyJet printing. Homogeneous 3-Dimensional test configuration employed in the present study eliminates the process-induced limitations of traditional ASTM D638 2D fatigue test coupons for AM processed materials. Fatigue data is analyzed to present an empirical model of effective elastic modulus and an analytical model of the accumulated damage state, as defined on the basis of stiffness degradation during cyclic loading. Further, the actual damage accumulation due to cyclic loading with the predicted model is compared. Modeling of the S-N diagram provides a better estimation of fatigue life and fatigue life modeling of AM printed test coupons and is obtained via linear regression analysis of experimental data with high correlation coefficient R2 (0.9971). The analytical model of the accumulated damage state is based on the stiffness degradation and is derived from the regression analysis of experimental data of stiffness degradation at different loading percentages assuming a polynomial of degree 4. Present study provides insight into the fatigue damage state and cyclic performance of digital polypropylene from Polyjet printing.

Yield Point Determination Using Cyclic Loading in Polymer

2018 ◽  
Author(s):  
Lucas K. Ychisawa ◽  
Celio A. Costa
Keyword(s):  
Cyclic Loading ◽  
Stress Relaxation ◽  
Oil And Gas ◽  
Cyclic Hardening ◽  
Oil And Gas Industry ◽  
Polymer Materials ◽  
Elastic Behavior ◽  
Gas Industry ◽  
Cyclic Loading Tests ◽  
Yielding Point

Defining the yielding point of semicrystalline polymers is a matter to be established in the literature. ASTM D638-14 and ISO 527-1 standards define the yielding point as the point where there is an increase in strain without an increase in stress, which coincides with the beginning of necking of the test samples. The literature has been reevaluating this matter, taking into account the methods used and their respective damage generation in the material. Polymer materials are used in the oil and gas industry, for example, in risers. The understanding of the transition between the elastic and plastic regions is necessary, as well as the understanding of the damage done in both regions. This study is about the effects of cyclic loadings with triangular and sinusoidal loading, with different strain levels and their effect on the mechanical behavior of a fluorinated polymer(Halar ECTFE). The cyclic loading tests were strain-controlled and done with frequencies around 0.1Hz, equivalent to a strain rate of 0.2 and 0.4%/s, and strains up to 2%, with the effects on the transition from the elastic and on the stress relaxation being observed. The results show that up to strains of 0.5% the material has elastic behavior, irrespective of the loading. When the strains are greater than 0.75%, the material shows relaxation on all loadings cycles. Between 0.5% and 0.75%, the triangular loading led to cyclic hardening, while the sinusoidal lead to stress relaxation. The stress relaxation is then related to the damage accumulation on the structure of the material, while the hardening to the chain orientation.

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