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Tytuł:
Shear performance of reinforced self-compacting concrete beams incorporating steel and polypropylene fibers
Autorzy:
Alkhattat, Saja S.
Al-Ramahee, Munaf A.
Powiązania:
https://bibliotekanauki.pl/articles/35550882.pdf
Data publikacji:
2021
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
steel fiber
lightweight concrete
polypropylene fibre
shear strength
Opis:
The impact of steel and polypropylene fibers on the performance of lightweight self-compacting concrete (LWSCC) beams was investigated in this study. Seven beams with various parameters were cast and tested. Partial (50%) and full (100%) replacement of coarse aggregate with lightweight aggregate expanded clay (LECA) were considered. In addition, a 1% volumetric ratio of steel or hybrid (steel and polypropylene) fiber was added to LWSCC beams to study their effect on the shear performance. The LWSCC beams had a decrease in ultimate load and stiffness of 23 and 30% for partial and full replacement, respectively when compared to normal weight beam. The addition of steel fiber improved the efficiency of LWSCC beams in terms of crack formation, failure mode, crack width, and ultimate load, as well as changed the failure mode from shear to flexure. The ultimate load for hybrid LWSCC was increased by around 6% for a partial replacement and 13% for full replacement as compared to beams without fibers. However, hybrid beams had a larger bearing capacity, little more cracks with smaller size, and ductile failure.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2021, 30, 4; 537-551
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza wpływu wysokiej temperatury na zmianę wybranych parametrów wytrzymałościowych fibrobetonu z dodatkiem włókien polipropylenowych
Analysis of influence of high temperature on changes of the selected strength parameters of fiber reinforced concrete with polypropylene fibers
Autorzy:
Bednarek, Z.
Drzymała, T.
Powiązania:
https://bibliotekanauki.pl/articles/136914.pdf
Data publikacji:
2013
Wydawca:
Szkoła Główna Służby Pożarniczej
Tematy:
pożar
fibrobeton
włókna polipropylenowe (PP)
wytrzymałość
moduł sprężystości
fire
fibers reinorced concerete (FRC)
polypropylene fibre
elastic modul
Opis:
W niniejszym referacie autorzy zaprezentowali wyniki badań wytrzymałościowych, których celem była analiza oddziaływania wysokich temperatur występujących podczas pożaru na wytrzymałość fibrobetonu z włóknami polipropylenowymi oraz oszacowanie wielkości spadku wytrzymałości na ściskanie w porównaniu z betonem tej samej klasy bez dodatku włókien. Dodatkowo omówiono procedury badawcze oraz wyniki badań modułu sprężystości fibrobetonu z dodatkiem włókien polipropylenowych poddanego oddziaływaniu wysokiej temperatury zbliżonej do temperatury występującej w środowisku pożaru. Podczas badań stwierdzono korzystny wpływ dodatku włókien polipropylenowych w ilości 1,2 kg/m3 oraz dozowanych do mieszanki betonowej powyżej 1,2 kg/m3 na właściwości wytrzymałościowe betonu w wysokich temperaturach.
In construction engineering practice impact of high temperatures occurring during fire on the concrete structures is an important issue. An unfavorable phenomenon associated with high temperature is surface spalling of large concrete parts, which has a significant impact on the safety of the whole building structure, users and rescue teams. “Concrete thermal spalling” phenomenon in the foreign literature is called “spalling“. One of the possibilities of preventing this negative phenomenon is a technological method consisting in addition of polypropylene fibers to concrete mix. The method results in the increase of resistance of the concrete structure to the explosive spalling in the conditions of increased humidity. In the road tunnels and other non-heated compartments, concrete is characterized by the relatively high water content. The results of many tests prove that the addition of polypropylene fibers (PP) can have a positive impact on the concrete structures subjected to high temperatures and can reflect to the reduction of “spalling” effect. Investigations of high temperatures impact occurring during the fire, on the basic strength parameters of the concrete with addition of polypropylene fibers, were carried out in Poland, at Cracow University of Technology and Main School of Fire Services, among the others. Zoja Bednarek and Tomasz Drzymala conducted investigations at the Main School of Fire Services. During the studies advantageous effect of the addition of 1.2 kg/m3 and above of polypropylene fibers to the concrete mix on the concrete strength properties at high temperatures have been demonstrated. In the presented paper the results of strength tests are shown, which aimed at analyzing the impact of high temperatures occurring during the fire on the strength of fiber reinforced concrete with polypropylene fibers, as well as estimating reduction of compressive strength compared to the concrete of the same class but without addition of fibers. Additionally, the applied research methods are discussed and elasticity modulus test results of fiber reinforced concrete subjected to high temperatures close to fire temperatures are presented. Taking into account the undoubtedly positive influence of PP fibers addition on the reduction of concrete “spalling”, the authors investigated the manner in which such addition influences different strength properties of the concrete at high temperatures conditions. From this point of view the impact of high temperatures on the compressive strength and elasticity modulus were investigated. Samples were prepared with the use of normal C30/37 class concrete and high strength C60/75 class concrete. For the concrete mix three different types of polypropylene fibers were used, differing in length and thickness of single fibers, in the following amount: 0.6 kg/m3, 0.9 kg/m3, and 1.2 kg/m3. The selected fibers used as the additives to concrete mix are easily available on the European market. Preliminary studies were carried out to deter-mine the influence of fire temperatures on the flammable properties of fibers in oxygen and nitrogen atmosphere. The conducted studies have demonstrated a significant impact of the atmosphere, in which degradation of samples take place, on the results of TG and DTG analysis. The atmosphere had a crucial effect on the initial temperature of degradation, temperature of the partial mass loss, temperature of termination of degradation, temperature of maximum mass loss rate and nondegradable residues mass remaining in the concrete. The results of the studies allow assuming that in the condi-tions of oxygen depletion, degradation of PP fibers in the concrete would occur much slower. The above assumption has been confirmed by the observations of the concrete structure, by means of scanning microscope (SEM), with regards to the fibers condition inside the concrete samples. Based on the obtained results the following conclusions have been formulated: 1. The addition of PP fibers has a negative impact on the compressive strength of C30/37 class concrete, especially in normal temperatures and temperatures raised to about 200ºC. Above 300ºC a reduction of strength of this concrete is identical to the strength reduction of the concrete without PP fiber addition. 2. In case of fiber reinforced concrete and C60/75 class concrete, compressive strength reduction in the whole temperature range can be considered as identical. 3. No significant influence of the type of the applied PP fibers on the reduction of compressive strength for both classes of fiber reinforced concrete has been demonstrated. 4. In case of both classes of fiber reinforced concrete the compressive strength is reduced in high temperatures. Moreover, the strength reduction of C30/37 concrete proceeds faster. At 800ºC the strength of normal concrete and fiber reinforced concrete of C30/37 class decreases of about 90%, whereas in case of concrete and fiber reinforced concrete of C60/75 class such reduction occurs at 1000ºC. 5. Analyzing the results with regards to the impact of PP fibers addition to the concrete in the quantities above 1.2 kg/m3, it can be concluded that such addition does not enhance strength reduction of the concrete in fire temperatures. Therefore, in case of fiber reinforced concrete the identical principles can be applied for strength determination, as in case of the concrete without PP fibers in fire temperatures. The reduced compressive strength of the concrete with addition of PP fibers in temperature T can be described by the following formula: fck(T) = kc (T) ... fck ---- (1) where: fck – specific compressive strength of fiber reinforced concrete at normal temperature (20ºC) kc(T) – assumed reduction coefficient as for the corresponding class concrete without addition of fibers. 6. Based on the results analysis a positive impact of PP addition on the elasticity modulus of C30/37 and C60/75 class concrete in high fire temperatures can be concluded. 7. In both cases higher growing tendencies have been observed for C30/37. In normal temperature no impact of PP fibers addition on the elasticity modulus values can be noticed. 8. At the elevated and high temperatures a slightly lower elasticity modulus reduction in case of fiber reinforced concrete with PP fibers can be observed. It is especially evident at 300ºC. Summing up: addition of 1.2 kg/m3 of polypropylene fibers to the concrete, in order to reinforce the concrete against dangerous explosive spalling during the fire, is advantageous also from the point of view of the concrete strength at fire temperatures.
Źródło:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej; 2013, 3, 47; 127-138
0239-5223
Pojawia się w:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of randomly distributed polypropylene fiber reinforcement on the shear behavior of sandy soil
Autorzy:
Benziane, Mehdi Missoum
Della, Noureddine
Denine, Sidali
Sert, Sedat
Nouri, Said
Powiązania:
https://bibliotekanauki.pl/articles/178213.pdf
Data publikacji:
2019
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
sand
direct shear box tests
polypropylene fibre
shear strength
normal stress
relative density
Opis:
The inclusions of geosynthetic materials (fibers, geomembranes and geotextiles) is a new improvement technique that ensures uniformity in the soil during construction. The use of tension resisting discreet inclusions like polypropylene fibers has attracted a significant amount of attention these past years in the improvement of soil performance in a cost-efficient manner. A series of direct shear box tests were conducted on unreinforced and reinforced Chlef sand with different contents of fibers (0, 0.25, 0.5 and0.75%) in order to study the mechanical behavior of sand reinforced with polypropylene fibers. Samples were prepared at three different relative densities 30%, 50% and 80% representing loose, medium dense and dense states, respectively, and performed at normal stresses of 50, 100 and 200 kPa. The experimental results show that the mechanical characteristics are improved with the addition of polypropylene fibers. The inclusion of randomly distributed fibers has a significant effect on the shear strength and dilation of sandy soil. The increase in strength is a function of fiber content, where it has been shown that the mechanical characteristics improve with the increase in fiber content up to 0.75%, this improvement is more significant at a higher normal stress and relative density.
Źródło:
Studia Geotechnica et Mechanica; 2019, 41, 3; 151-159
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling of pneumatic melt drawing of polypropylene super-thin fibers in the Laval nozzle
Autorzy:
Blim, A.
Jarecki, L.
Blonski, S.
Powiązania:
https://bibliotekanauki.pl/articles/201530.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
air drawing
Laval nozzle
pneumatic melt spinning
superthin fiber
Opis:
Melt spinning of the fibers by supersonic air jet in the Laval nozzle is a novel, efficient and energy saving method of formation of super-thin fibers. In the process, polymer melt is extruded from a row of orifices and fast drawn by the pneumatic forces. In the modelling, air velocity, temperature and pressure distributions are computed from the k-! aerodynamic model. Computations of the polymer air-drawing dynamics are based on the mathematical model of melt spinning in a single-, thin-filament approximation and Phan-Thien/Tanner non-linear viscoelasticity of the polymer melt. Axial profiles of the polymer velocity, temperature, tensile stress and rheological extra-pressure are computed. Influence of the Laval nozzle geometry, initial air compression, an initial melt temperature, a polymer mass output and the diameter of the melt extrusion die is discussed. The role of the polymer molecular weight, melt viscosity and relaxation time is considered. Example computations show the influence of important processing and material parameters. In the supersonic process, a high negative internal extra-pressure is predicted in the polymer melt under high elongation rates which may lead to cavitation and longitudinal burst splitting of the filament into a high number of sub-filaments. A hypothetical number of sub-filaments at the splitting is estimated from an energetic criterion. The diameter of the sub-filaments may reach the range of nano-fibers. A substantial influence of the Laval nozzle geometry is also predicted.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2014, 62, 1; 43-54
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamic Behavior of a Clayey Sand Reinforced with Polypropylene Fiber
Autorzy:
Bozyigit, I.
Tanrinian, N.
Karakan, E.
Sezer, A.
Erdoğan, D.
Altun, S.
Powiązania:
https://bibliotekanauki.pl/articles/1031269.pdf
Data publikacji:
2017-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.70.Bt
83.80.Fg
Opis:
It is a well-identified fact that more elaborate laboratory studies should be carried out for evaluation of dynamic properties of different types of soils. Regardless of the mechanisms affecting the mechanical behaviour of the soils, past studies reveal that existence of fiber positively affects the strength of either cohesive or non-cohesive soils. A short literature survey provides numerous studies on the stress-strain behaviour of fine/coarse soils, reinforced by polypropylene fiber. On the other hand, studies concerning fiber reinforced soils subjected to dynamic loading are relatively rare. Therefore, in this research it was intended to investigate the effects of polypropylene fiber inclusion on the dynamic behavior of a clayey sand soil, within an experimental framework. In this scope, a number of cyclic triaxial compression tests were conducted to assess the effect of fiber presence. The effects of fiber length and content were experimentally evaluated. Hence, the variation of shear modulus ratio and damping ratio values by shear deformation was plotted to observe the effects of fiber length and inclusion level as well. The results are presented along with detailed evaluations.
Źródło:
Acta Physica Polonica A; 2017, 132, 3; 674-678
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Radiation Shielding Properties of Polypropylene Fiber Reinforced Shotcrete
Autorzy:
Çakıroğlu, M.
Powiązania:
https://bibliotekanauki.pl/articles/1186770.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
78.20.Ci
Opis:
Fibre concrete has emerged in order to improve the properties of concrete and to create an economical building material. In this study, the radiation permeability of shotcrete reinforced with polypropylene fiber was investigated. For this purpose, linear attenuation coefficient was measured for shotcrete reinforced with polypropylene fiber, produced using the dry mixing process. The linear attenuation coefficients for dry mixed shotcrete have been measured at photon energies of 1173, 1332 and 662 keV. Measurements were carried out using gamma spectrometer containing NaI (Tl) detector and a Multichannel Analyzer (MCA). The linear attenuation coefficients have increased with the increasing fiber percentage for all studied gamma energies.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 705-706
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analiza zachowania się włókien polipropylenowych stosowanych do fibrobetonu w temperaturach pożarowych
Analysis of behaviour of polypropylene fibers applied for reinforcing of fiber reinforced concrete in fire temperatures
Autorzy:
Drzymała, T.
Półka, M.
Powiązania:
https://bibliotekanauki.pl/articles/136584.pdf
Data publikacji:
2011
Wydawca:
Szkoła Główna Służby Pożarniczej
Tematy:
technologia tworzyw sztucznych
włókna polipropylenowe
spalanie polipropylenu
Opis:
W artykule przedstawiono analizę wybranych właściwości palnych trzech rodzajów włókien polipropylenowych (PP), stosowanych jako dodatki do betonów. W badaniach eksperymentalnych oznaczono temperaturę zapalenia, ciepło spalania oraz dokonano analiz termograwimetrycznych (TG) dla badanych włókien polipropylenowych.
TG and DTG tests conducted in nitrogen let us suppose that the se fibers encapsulated in concrete in conditions of higher temperature and without access to a sufficient amount of oxygen shall be subject to pyrolysis in the similar way. Taking into account temperatures of maximum velocity of mass loss it may be stated that in these conditions the mass of „F” fiber shall be lost most quickly, then „D” fiber and finally „I” fiber.
Źródło:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej; 2011, 42; 53-62
0239-5223
Pojawia się w:
Zeszyty Naukowe SGSP / Szkoła Główna Służby Pożarniczej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Durability of hybrid fiber reinforced concrete at various environmental media
Autorzy:
Elhawary, Eslam Ibrahim Nasr
Elsafoury, Ashraf Hassan
Ahmad, Seleem Saleh Elsayed
Powiązania:
https://bibliotekanauki.pl/articles/35555212.pdf
Data publikacji:
2022
Wydawca:
Szkoła Główna Gospodarstwa Wiejskiego w Warszawie. Wydawnictwo Szkoły Głównej Gospodarstwa Wiejskiego w Warszawie
Tematy:
durability
hybrid fiber concrete
steel fiber
polypropylene fibre
compressive strength
splitting tensile strength
flexural strength
Opis:
Fiber’s addition to concrete mixture attracts researchers to determine the effect of fiber type on durability properties of hybrid performance concrete. In the present work, steel and polypropylene fibers are used in hybrid form in the experimental program. The objective of this paper is to investigate the mechanical properties of hybrid fiber reinforced concrete subjected to four various media: air, water, sodium chloride, and magnesium sulphate with a 7% concentration. The results showed that using hybrid fibers which consist of 1% steel fiber and 0.3% polypropylene fiber improved the compressive strength, splitting tensile strength, and flexural strength for different media for up to 360 days.
Źródło:
Scientific Review Engineering and Environmental Sciences; 2022, 31, 2; 88-100
1732-9353
Pojawia się w:
Scientific Review Engineering and Environmental Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Non-destructive characterisation of mortars reinforced with various fibres exposed to high temperature
Autorzy:
Ezziane, M.
Molez, L.
Messaoudene, I.
Powiązania:
https://bibliotekanauki.pl/articles/89226.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Wydział Geoinżynierii, Górnictwa i Geologii. Instytut Górnictwa
Tematy:
mortars
steel fiber
polypropylene fibre
temperature
non-destructive test
Opis:
The objective of this study is to investigate the effect of temperature on the physical and mechanical properties of standard mortar reinforced with steel fibers, polypropylene fibers and hybrid fibers. Non-destructive tests (capillary water absorption, interconnected porosity, gas permeability, ultrasound celerity) were carried out on samples that had been heated, at a temperature ramp of 5 °C/min, to maximum temperature of: 105 °C, 400 °C, 500 °C et 800 °C. The results show a good correlation between the evolution of properties and the damage resulting from the imposed heat exposure treatment. The study shows that there is a significant deterioration of physico-mechanical properties of the fiber mortars above 500 °C. The hybrid fiber mortars show a good compromise: the polypropylene fibers guarantee a thermal stability whereas the steel fibers act to conserve good mechanical behavior.
Źródło:
Mining Science; 2018, 25; 179-194
2300-9586
2353-5423
Pojawia się w:
Mining Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effect of transplanting date and covering on the growth and development of melon (Cucumis melo L.)
Wpływ terminu sadzenia rozsady i osłaniania na wzrost i rozwój melona (Cucumis melo L.)
Autorzy:
Franczuk, Jolanta
Rosa, Robert
Kosterna-Kelle, Edyta
Zaniewicz-Bajkowska, Anna
Panasz, Marzena
Powiązania:
https://bibliotekanauki.pl/articles/1590682.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Botaniczne
Tematy:
Cucumis melo
transplanting date
growth attributes
polypropylene fiber
yields
Opis:
The effect of different transplanting dates (May 15, May 25, and June 4) and date of polypropylene fiber removal (4 and 8 weeks after transplanting, and control without covering) on the growth, development, and yield of melon (Cucumis melo L.) were investigated. The experiment was carried out during 2008–2010 in eastern Poland (51°53'23.64" N, 22°27'47.96" E). Plants planted on May 15 were longer by 22% and 56%, weighed more by 39% and 76%, and their leaf area index (LAI) was higher by 24% and 117% compared to plants planted on May 24 and June 4, respectively. However, delayed planting reduced the period of growth and development by 7 and 17 days, respectively. When the covering application period was extended from 4 to 8 weeks, stem length increased by an average of 23% and LAI by 38%, but harvest was delayed by 6 days. The respective yields of melon fruits planted on May 15, May 25, and June 4 amounted to 5.09, 4.73, and 3.99 kg m−2. The covering of plants planted at each date contributed to an increase in yield and in the share of marketable fruit yield in the total yield. However, the length of the cover application period did not affect yield levels.
Celem badań była ocena zróżnicowanego terminu sadzenia rozsady (15 i 25 maja oraz 4 czerwca) oraz terminu zdjęcia osłony (4 i 8 tygodni po posadzeniu rozsady, kontrolna bez osłaniania) na wzrost, rozwój i plonowanie melona (Cucumis melo L.). Eksperyment polowy przeprowadzono w latach 2008–2010 w środkowo-wschodniej Polsce (51°53'23.64" N, 22°27'47.96" E). Rośliny posadzone 15 maja charakteryzowały się większą o 22% i 56% długością łodyg, o 39% i 76% masą oraz o 24% i 117% większym LAI w porównaniu z posadzonymi 24 maja i 4 czerwca. Jednak późniejsze sadzenie roślin powodowało skracanie okresu wegetacji odpowiednio o 7 i 17 dni. Wydłużanie okresu osłaniania roślin z 4 do 8 tygodni powodowało wzrost długości łodyg średnio o 23%, wskaźnika LAI o 38%, ale opóźniało zbiór średnio o 6 dni. Plon owoców melona posadzonego 15 maja wyniósł średnio 5.09 kg m2, posadzonego 25 maja 4.73 kg m2, a 4 czerwca 3.99 kg m2. Osłanianie roślin sadzonych w każdym terminie powodowało wzrost plonu oraz zwiększało udział plonu handlowego owoców w plonie ogółem. Jednak długość okresu osłaniania nie różnicowało wielkości plonów.
Źródło:
Acta Agrobotanica; 2017, 70, 2
0065-0951
2300-357X
Pojawia się w:
Acta Agrobotanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Strengthening and toughening mechanisms for polypropylene/Glass fiber composite foams under three-phase coexistence
Mechanizmy wzmacniające i utwardzające pianki kompozytowe polipropylen/włókno szklane w warunkach współistnienia trzech faz
Autorzy:
Gong, W.
Yu, J.
Fu, H.
Zhang, C.
He, L.
Powiązania:
https://bibliotekanauki.pl/articles/947491.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Chemii Przemysłowej
Tematy:
polypropylene
composite
foam
mechanical properties
polipropylen
kompozyt
pianka
właściwości mechaniczne
Opis:
Composite foams were obtained through a two-step molding process in an injection molding machine. Gas phase was introduced into the mixture of molten polypropylene (PP) and solid glass fiber (GF). The interfacial behavior was investigated, and the strengthening and toughening mechanisms for PP/GF composites under three-phase coexistence were discussed. The incorporation of gas phase significantly increased the tensile strength by 112 % and impact toughness by 105 % in comparison to its unfoamed counterpart. The resulting mechanical properties of the PP/GF composite foams were found to depend considerably on the coexistence state of solid (GF) and gas (cells) phases and the cell structure of the foams.
Pianki kompozytowe otrzymano w dwustopniowym procesie formowania wtryskowego. Fazę gazową wprowadzano do mieszaniny stopionego polipropylenu (PP) ze stałymi włóknami szklanymi (GF). Badano właściwości mechaniczne otrzymanych pianek PP/GF oraz omówiono mechanizmy powodujące wzmacnianie i utwardzanie tych pianek w warunkach współistnienia trzech faz. Zaobserwowano, że wprowadzenie fazy gazowej znacznie zwiększa wytrzymałość na rozciąganie (o 112 %) i udarność pianki (o 105 %) w porównaniu z wartościami otrzymanymi w przypadku jej niespienionego odpowiednika. Stwierdzono, że właściwości mechaniczne pianek kompozytowych PP/GF w znacznym stopniu zależą od stanu współistnienia fazy stałej (GF) i gazowej (pory) oraz struktury komórkowej pianki.
Źródło:
Polimery; 2015, 60, 7-8; 457-461
0032-2725
Pojawia się w:
Polimery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Micromechanical Investigation of Elastic Properties for Polypropylene Fiber-Matrix Composite
Autorzy:
Günay, E.
Powiązania:
https://bibliotekanauki.pl/articles/1033377.pdf
Data publikacji:
2017-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
62.23.Pq
81.05.Qk
62.20.de
62.20.dj
02.70.Dh
Opis:
In this study, the mechanical properties of unidirectional fiber composites were determined by using the representative volume element method. The aim of this study was to determine the equivalent elastic constants for the "fiber composite polymer (PPE/PP) thermoplastic material" used in a wide variety of engineering applications. At the first step, the micromechanical model was applied to the polypropylene (PP) fiber-matrix composite, and then the microstructure form of the material was analyzed by finite element method considering "rule of mixture". The symmetry boundary conditions have been applied by using the representative volume elements in 3D finite element models. The SOLID187 mesh element of ANSYS was used for the presentation of the microstructure form of the fiber-matrix composite. The elastic constants obtained in this study were respectively as follows: the longitudinal elastic modulus and the Poisson ratio E₁, ν₁₂, the transverse elastic modulus and the Poisson ratio E₂, ν₂₃. For verification, the numerical results were also compared with the literature.
Źródło:
Acta Physica Polonica A; 2017, 131, 1; 143-146
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of dosing with propylene fibers on the mechanical properties of concretes
Autorzy:
Helbrych, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/2174983.pdf
Data publikacji:
2021
Wydawca:
Politechnika Częstochowska
Tematy:
włókna polipropylenowe
dozowanie
matryca cementowa
beton zbrojony włóknami
właściwości mechaniczne betonu
polypropylene fiber
dosing
cement matrix
fiber reinforced concrete
concrete mechanical properties
Opis:
The article deals with the suitability of polypropylene fibers in concrete mixtures and the impact related to the amount of dosing of such fibers. The amount of addition in the range from 0.5 to 2.0 kg/m3 was analyzed and the effects of dosing too little or too much fiber in concrete in terms of its mechanical strength were discussed. The test fibers were made of white polypropylene arranged in bundles 50 mm long. The samples were tested after 28 days of maturation, and the mechanical properties that were assessed included, the compressive strength and the tensile strength of the concrete in a bend test. The influence of the amount of fibers on the consistency of the concrete mixture was also investigated. The results were statistically analyzed and presented in the article.
Źródło:
Budownictwo o Zoptymalizowanym Potencjale Energetycznym; 2021, 10, 2; 39--44
2299-8535
2544-963X
Pojawia się w:
Budownictwo o Zoptymalizowanym Potencjale Energetycznym
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mechanical properties of concretes modified with steel fibers and polypropylene
Autorzy:
Helbrych, Paweł
Powiązania:
https://bibliotekanauki.pl/articles/24202547.pdf
Data publikacji:
2022
Wydawca:
Akademia Morska w Szczecinie. Wydawnictwo AMSz
Tematy:
polypropylene fibre
steel fibers
fiber-reinforced concrete
concrete
mechanical properties
Opis:
This paper presents the effect of the addition of steel and propylene fibers on the mechanical properties of floor concretes (compressive and tensile strengths in the bending test). The polypropylene fibers used in the tests (fibrillated and single fibers) are dosed in the amount of 0.5 kg/m3 to 2 kg/m3 , and the straight and hooked steel is dosed from 10 kg/m3 to 25 kg/m3 . It is shown that, after 28 days of maturation, the highest compressive strength is achieved by concretes containing the addition of 25 kg/m3 of hook-like steel fiber. In addition, the influence of the fiber content on the consistency of the concrete mix and workability is investigated. It was shown that the amount of steel fibers dosed in the tests, regardless of their shape, did not adversely affect the consistency and workability of the concrete mix. On the other hand, the addition of polypropylene fibers has a significant impact on the characteristics of the concrete mix. The addition of 2 kg/m3 of polypropylene fibers caused the change of consistency from S4 to S1/S2 and worsened the workability of the mixture. All of the tested series of the concrete are created using the same technology. The concrete production technology reflects the concrete production technology for flooring concretes.
Źródło:
Zeszyty Naukowe Akademii Morskiej w Szczecinie; 2022, 71 (143); 56--63
1733-8670
2392-0378
Pojawia się w:
Zeszyty Naukowe Akademii Morskiej w Szczecinie
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Waste Toothbrush Fiber on Strength and Freezing–Thawing Behavior in High Plasticity Clay
Autorzy:
Isik, Fatih
Akbulut, R. Kagan
Zaimoglu, A. Sahin
Powiązania:
https://bibliotekanauki.pl/articles/1845156.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
waste material
polypropylene fiber
toothbrush bristle
freezing–thawing
unconfined compression test
reinforced clay
Opis:
The use of waste materials in civil engineering applications has gained importance nowadays. Consuming limited natural resources and increasing waste disposal costs have led researchers to evaluate waste materials for different geotechnical applications. In this respect, some waste materials are used as reinforcement in soils to improve their engineering properties. The main objective of this paper was to investigate the usability of waste polypropylene fiber as a reinforcement material in high plasticity fine-grained soils. For this purpose, waste toothbrush bristle (WTB) was used as a polypropylene fiber reinforcement material and added to fine-grained soil at ratios of 0.2%, 0.4%, 0.6% and 0.8% by dry total weight. The effect of WTB on freezing–thawing behavior and unconfined compression strength of unreinforced and reinforced clayey soil was evaluated. The results indicated that addition of WTB to high plasticity clay improved its behavior against freezing–thawing. Also, undrained shear strength increases with respect to increment in WTB ratio.
Źródło:
Studia Geotechnica et Mechanica; 2021, 43, 1; 15--21
0137-6365
2083-831X
Pojawia się w:
Studia Geotechnica et Mechanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 29

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