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1

Influence of joint spacing on weathering and soil formation on a morphologically diverse sandstone cliff (Stołowe Mountains tableland, SW Poland)

Kacprzak Andrzej, Duszyński Filip, Jancewicz Kacper, Konieczny Kacper, Porębna Wioleta, Sadkiewicz Marta, Shythsik Stanislau, Toszek Julia, Waroszewski Jarosław, Wieczorek Małgorzata, Woźniak Magdalena

Landform Analysis

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2025

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Vol. 44

77--88

EN

The research presented in this paper was conducted in the Stołowe Mts. and addressed litho-structural controls on sandstone decay at Białe Skały. We tested the working hypothesis that densely jointed, disintegrated zones exhibit increased moisture that fosters arenization, resulting in reduced surface strength. Geomorphological mapping, structural measurements, Schmidt-hammer rebound testing, and rock-moisture surveys with three handheld metering devices of differing penetration depths were undertaken. Rebound values confirmed significantly lower surface strength in disintegrated zones. Moisture measurements yielded equivocal results at different depths; only near-surface readings indicated higher values after antecedent rainfall. Together with deeper, organic-rich soils in disintegrated sectors, the evidence supports joint-guided weakening and recessed cliff development. Further depth-resolved moisture monitoring is recommended.

2

Mechanical strengths, durability, and corrosion resistance of concrete with recycled sand

Kherraf Leila, Kherraf Sihem, Khaldi Nacera, Belachia Mouloud

Ecological Chemistry and Engineering. S

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2025

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Vol. 32, nr 1

113--137

EN

The reuse of construction and demolition waste is undoubtedly one of the main research focuses today for reducing waste and preserving the environment within the framework of sustainable development. The objective of this work is to study the effects of varying the dosage of unbaked clinker waste sand (CWS) and recycled concrete sand (RCS), at an age of approximately 28 days, previously to produce compressed pipes, on the physical properties of the fresh and hardened states, as well as the corrosion resistance of ordinary concrete. The analysed concrete mixes contain recycled sand in percentages of (0, 5, 10, 15, and 20) %, in addition to limestone crushed sand. The tested concrete characteristics include density, workability, compressive and flexural strength, splitting tensile strength, water absorption by immersion and capillarity, and resistance to chemical attacks by 5 % CH3COOH and 5 % NaCl. The corrosion behaviour of steel bars in 3.5 % NaCl solution is monitored using electrochemical methods, including potentiodynamic polarisation and electrochemical impedance spectroscopy. The results obtained show that the use of recycled sands leads to a reduction in concrete workability, improvement in compressive, flexural, and splitting tensile strength, and a reduction in water absorption capacity, which could be directly related to modifications in the microstructure. The electrochemical results indicate that the addition of CWS and RCS in concrete greatly affect the corrosion resistance properties of concrete. The corrosion resistance increases with increasing immersion time up to 40 days, after which it decreases, indicating a loss of protective ability.

3

Impact of low-density polyethylene (LDPE) waste on the physico-mechanical and durability behavior of lime-stabilized adobe bricks

Soumia Hammache, Izemmouren Ouarda, Guettala Abdelhamid

Budownictwo i Architektura

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2025

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Vol. 24, no 4

25009 (1--14)

EN

Earth-based construction techniques, such as adobe, are valued for their low cost and reduced environmental impact. However, their limited mechanical strength and poor water resistance reduce their overall durability. This study investigates the improvement of adobe bricks through the addition of lime and low-density polyethylene (LDPE) plastic waste derived from greenhouse cleaning activities, in varying proportions (2–6%) and fiber lengths (10–30 mm). The research aims to evaluate the physical, mechanical, and durability characteristics of the modified earth blocks. The results show a reduction of 23.57% in density, 17.95% in ultrasonic pulse velocity, and 37.80% in compressive strength. While the lower compressive strength reflects a mechanical limitation, the decrease in density could be beneficial for lightweight applications or for improving the thermal and acoustic insulation of walls. Conversely, notable improvements were recorded in tensile strength and abrasion resistance, which increased by 71.42% and 90.47%, respectively. Despite these benefits, the mixtures exhibited slightly higher water absorption and swelling, indicating increased sensitivity to moisture. Nevertheless, the reduced mass loss after wetting-drying cycles highlights an overall improvement in the long-term durability of the material.

4

Evaluation of friction stir welding on the microstructure and mechanical properties of dissimilar aluminum alloys 5083-O and 6061-T6 for automotive applications

Haryadi Gunawan Dwi, Taufik Muhammad Zaidan, Rochadian Okpina, Caesarendra Wahyu, Żak Krzysztof

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 9

34--49

EN

The Friction Stir Welding (FSW) process, employed for joining aluminium alloys, particularly the 5xxx and 6xxx series, is widely utilized in various applications, notably within the automotive industry. These alloy series exhibit properties that render them ideal for manufacturing components such as frames, chassis, and pistons due to their lightweight, strength, and corrosion resistance. FSW is especially advantageous as it presents an environmentally friendly alternative for aluminium welding, characterized by its low melting point, which facilitates precise thermal control during the welding process. This investigation focuses on the impact of FSW process parameters on the microstructure and mechanical properties of 5083-O and 6061-T6 aluminium alloys, Optimal welding conditions were determined to be a tool rotational speed of 1400 RPM, a travel speed of 30 mm/s, and a tool tilt angle of 1°. Under these parameters, a tensile strength efficiency of 75% relative to the 5083-O base material was achieved, with a maximum tensile strength recorded at 203.8449 MPa and a hardness range of 70.1-70.5 HV. Microstructural analysis reveals a clean weld surface devoid of significant defects that could compromise weld quality. The material exhibited equiaxed recrystallized grains in the WN zone under optimal parameters. Conversely, the most vulnerable aspect of the welded joint was consistently identified within the Heat Affected Zone (HAZ) of the 6061-T6 side across all parameter configurations. This susceptibility is attributed to grain growth and the dissolution of Mg2Si precipitates induced by the thermal effects during the FSW process, as corroborated by microphotographic analysis.

5

Enhancing the strength and durability of lime mortar with Acacia Seyal Gum: A sustainable solution for diverse climatic conditions

Suthaagaran Vallabhy, Selvaraj Thirumalini

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 3

47--62

EN

This study investigates the enhancement of lime mortar using Acacia Seyal Gum, a natural biopolymer, to improve its strength and durability under various environmental conditions. Mortar samples were prepared by adding Acacia Seyal Gum at 1%, 3%, and 5% by weight to its volume. The mechanical properties of the modified mortar were assessed under varying climatic conditions, specifically at temperatures of 25°C and 35°C and relative humidity levels of 20%, 50%, and 72%. The 3% gum-modified mortar showed the most significant improvement, exhibiting superior strength and durability compared to the reference mortar across all tested environments. Adding Acacia Seyal Gum improved the bond between lime and sand particles, decreased porosity, and increased moisture retention, which helped prevent early shrinkage and cracking. This study highlights the potential of Acacia Seyal Gum as a sustainable and effective additive for lime mortar, contributing to modern eco-friendly construction and the restoration of historic structures. The findings suggest that the gum-modified mortar could provide a reliable, durable, and environmentally responsible alternative to traditional lime mortars in regions with challenging environmental conditions.

6

Rola homogenizacji w predykcji nośności opakowań z tektury falistej – przegląd metod i zastosowań

Garbowski Tomasz

Przegląd Papierniczy

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2024

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R. 80, nr 5

271--278

PL

Artykuł omawia kluczową rolę homogenizacji w predykcji nośności opakowań z tektury falistej, podkreślając metody i techniki stosowane w tym procesie. Homogenizacja pozwala na uproszczenie złożonej struktury tektury falistej, co prowadzi do zwiększenia efektywności obliczeń i precyzyjniejszej predykcji wytrzymałości. Przegląd przedstawia różnorodne metody homogenizacji, takie jak: metoda Voigta-Reussa-Hill, Mori-Tanaki, metoda samouzgodniona oraz ich zastosowanie w modelowaniu właściwości mechanicznych. W pracy omówiono także zastosowanie metod numerycznych, w tym metody elemen tów skończonych (MES), które porównano z metodami eksperymentalnymi. Praktyczne zastosowania homogenizacji zilustrowano za pomocą studiów przypadków, ukazując korzyści w projektowaniu i optymalizacji opakowań. Przegląd wskazuje również na obecne wyzwania i przyszłe kierunki badań, podkreślając znaczenie wyników dla przemysłu opakowaniowego, zwłasz cza w kontekście poprawy wytrzymałości, efektywności materiałowej oraz optymalizacji kosztów produkcji.

EN

This article discusses the crucial role of homogenization in predicting the load-bearing capacity of corrugated board packaging, emphasizing the methods and techniques used in this process. Homogenization simplifies the complex structure of corrugated board, leading to increased com putational efficiency and more precise strength predictions. The review presents various homogenization methods, such as the Voigt-Reuss-Hill, Mori-Tanaka, and self-consistent methods, and their application in modeling mechanical properties. The article also discusses the use of numerical methods, including the finite element method (FEM), and compares them with experimental methods. Practical applications of homogenization are illustrated through case studies, highlighting the benefits in the design and optimization of packaging. The review also identifies current challenges and future research directions, emphasizing the importance of the results for the packaging industry, particularly in terms of improving strength, material efficiency, and production cost optimization.

7

Investigation of the properties of aluminous porcelain samples of a long-rod insulator subjected to high DC voltage

Wieczorek Krzysztof, Ranachowski Przemysław, Ranachowski Zbigniew, Brodecki Adam, Śmietanka Hubert

Przegląd Elektrotechniczny

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2024

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R. 100, nr 11

281--285

EN

The objective of this examination was to test the aging resistance of the aluminous porcelain material C 130 type, when exposed to direct current (DC) high voltage. Long-term exposure to high DC voltages can potentially lead to various negative effects, in particular ionic current development in the porcelain material. This process may reduce the mechanical strength and, consequently, cause a failure. This problem has been noticed in the case of glass disc insulators. The samples were examined using the 3-point bending test, ultrasonic and microscopic analysis. No recordable degradation effects were found. Long-term impact of DC high voltage did not reduce the mechanical parameters or change the microstructure of the porcelain material.

PL

Celem prezentowanych badań było sprawdzenie odporności na starzenie się wysokoglinowego materiału porcelanowego rodzaju C 130, w warunkach oddziaływania wysokiego napięcia prądu stałego (HVDC). Długotrwałe narażenie na wysokie napięcie prądu stałego może potencjalnie prowadzić do różnych negatywnych efektów, w szczególności do przepływu prądu jonowego w tworzywie porcelanowym. Proces taki może poważnie obniżyć wytrzymałość mechaniczną materiału. W konsekwencji mogłoby nastąpić pęknięcie izolatora i dojść do awarii. Problem ten był rejestrowany w przypadku izolatorów szklanych. Próbki poddano pomiarom ultradźwiękowym, badaniu wytrzymałości mechanicznej metodą 3- punktowego zginania oraz analizie mikroskopowej. Nie stwierdzono żadnych możliwych do rejestracji efektów degradacji. Długotrwałe działanie wysokiego napięcia prądu stałego nie spowodowało obniżenia parametrów mechanicznych ani zmian w mikrostrukturze materiału porcelanowego.

8

Wpływ modułu molowego SiO2/Na2O aktywatora na kształtowanie właściwości materiałów geopolimerowych

Wieczorek Alicja, Koniorczyk Marcin, Trzuskowska Monika, Wróbel Piotr

Inżynieria i Budownictwo

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2024

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R. 80, nr 6

453--457

PL

Celem pracy było określenie przydatności popiołu lotnego pochodzącego ze spalania węgla kamiennego w elektrociepłowni z terenu Łodzi do wytwarzania materiałów geopolimerowych. W pracy analizowano wpływ modułu molowego aktywatora (SiO2/Na2O) na proces przyrostu wytrzymałości w czasie zapraw modyfikowanych dodatkiem granulowanego żużla wielkopiecowego (0, 10 i 50% masowo względem popiołu lotnego). Ważnym aspektem przeprowadzonych analiz jest informacja o możliwości zagospodarowania lokalnie występujących produktów ubocznych po procesach przemysłowych.

EN

The objective of the study was to determine the suitability of fly ash derived from the combustion of hard coal in a heat and power plant located in Lodz to produce geopolymer. The study investigated the effect of the molar modulus of the activator (SiO2/Na2O) on the compressive strength over time in mortars modified with the addition of granulated blast furnace slag (0, 10 and 50%). An important aspect of the analyses is the possibility of managing locally occurring products from industrial processes.

9

Rheological and mechanical behavior study of eco-friendly cement mortar made with marble powder

Chahour Kahina, Mechakra Hamza, Safi Brahim, Dehbi Nacera-Melissa, Chaibet Cylia

International Journal of Applied Mechanics and Engineering

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2024

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Vol. 29, no. 1

19--35

EN

The work aim is to investigate the rheological and mechanical behavior of eco-friendly mortar made with marble powder. Marble have used as sand by total substitution of natural sand and as additional materials by partial substitution of cement. Firstly, rheological tests were carried out on the cement pastes in order to studying the effect of cement substitution by marble powder on the rheological behavior. Secondly, our study is devoted to evaluate the mechanical performances (flexural strength, compressive strength, mechanical behavior and ultrasonic pulse velocity) of a fluid mortar such as the case of the self-compacting mortars elaborated with the marble powder as addition materials and as a sand. The mechanical test results show that a significantly improved of compressive strength and mechanical behavior of an ecological cement mortar made with marble waste as a natural sand. However, marble-based mortars with 100% of marble sand have given a mechanical strength similar to that obtained by control cement mortar (100% natural sand). It was also noted that it can be obtained an ecological cement mortar made with 30% of marble powder as an addition supplementary materials. This leads to a reduction in cement consumption cad a reduction in CO2 gas emissions caused by cement production.

10

Comparison of shrinkage deformations in resin mortars modified with different waste materials

Dębska Bernardeta, Silva Guilherme Jorge Brigolini, Caetano Marina Altoé, Bruna Silva Almada

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2024

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Vol. 13

229-236

EN

Resin-based mortars are characterized by excellent strength parameters, together with very good chemical resistance and a short time to achieve installation and serviceability. However, a limitation of their use may be their relatively high curing shrinkage. This parameter can be improved by modifying the composition of mortars with, among other things, recycled materials. This article describes and compares the results of tests on four types of epoxy mortars: a control sample (unmodified) and three modified samples with waste polyethylene terephthalate glycolysate, each one containing additional waste polyethylene or rubber from car tires. A positive effect on the mechanical strength of the mortars was demonstrated thanks to the modification. The shrinkage of the mortars was monitored from the time of formation. The partial substitution of aggregate by rubber granules or polyethylene agglomerate reduced the shrinkage value of the mortars based on a glycolysate-modified matrix by 14.2 % and 7.1 %, respectively.

11

The Analysis of Influence of Compression Forces on the Strength of MM „Stahl 1018” Composite with the use of SolidWorks Software

Arustamian A., Kalisz Dorota

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 2

25--34

EN

Composite Multimetal Stahl 1018 has been used in the process of preserving worn surfaces of materials operating in extremely difficult conditions. This work presents the results of simulation of the mechanical properties of steel samples in contact with the MM "Stahl 1018" composite. Tests were carried out for various models with with one- and two-sided contact sample models with the composite. Theoretical tests were conducted in the "SolidWorks 2019" environment. It was found that the maximum strength of the specimen layer made of MM "Stahl 1018" material, which closely adheres to the surfaces of steel bases on both sides (444 MPa) is higher than that of the material layer in one-sided contact (358 MPa), for specimens with a height of 4.5 mm and at 80°C. Simulations also revealed a significant increase in the maximum stress in the composite MM "Stahl 1018" for specimens in the so-called free state from 285 MPa to 358 MPa with the increasing temperature from 20°C to 80°C, for specimens 4.5 mm high.

12

The influence of long-distance pumping on the workability, mechanical strength, and frost resistance of SCC

Hao Ji, Meng Yuhao, Cui Yan, Mu Jinlei, Li Yue, Sui Chune

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e91, 2024

EN

Concrete pumping technology is widely used in reservoirs, dams, harbours and other hydraulic structures. To investigate the effects of pumping on the flowability, mechanical strength and frost resistance of hydraulic concrete, long-distance pumping tests were carried out on self-compacting concrete (SCC). This paper investigated the influence of high-pressure pumping on the workability, mechanical strength and frost resistance of SCC by analysing the changes in various properties of SCC before and after long distance pumping. The flowability of the fresh concrete decreased after long-distance pumping. Compared to before pumping, the slump of the four groups of SCC decreased by an average of 3.93% and the slump-flow decreased by an average of 23.09%. The homogeneity and stability of the fresh SCC improved significantly after pumping. After pumping, the V-funnel time of SCC was reduced by an average of 82.32% and the segregation rate was reduced by an average of 125.76%. Additionally, there was a slight increase in mechanical strength indicated by an average increase of 5.87% in cubic compressive strength, 8.99% in axial compressive strength, 7.78% in tensile splitting strength, and 5.22% in modulus of elasticity. Notably, the frost resistance of the SCC showed significant improvement after pumping. Under non freeze-thaw conditions, the compressive strength of SCC after pumping increased by an average of 5.87%. After 200 freeze-thaw cycles, the compressive strength (after pumping) increased by an average of 12.46%. An air void analyser was then used to test the air-void parameters to analyse the effect of long-distance pumping action on the air voids parameters. The study further established the correlation between air-void structure characteristics and freeze-thaw resistance. Under freeze-thaw conditions, the compressive strength showed a linear correlation with air content and spacing factor. The process of pumping can enhance the air-void structure of SCC, leading to improved frost resistance. Therefore, in the design of concrete frost resistance, pumping can be considered as an influencing factor to improve the frost resistance of concrete.

13

Effect of unidirectional temperature conduction on the strength evolution of shotcrete in a high geothermal environment

Yuan Qiang, Xue Kaiwei, Zhang Suhui, Tian Yi, Hu Chaolong, Liu Xiao

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 2

art. no. e63, 2024

EN

The high geothermal environment causes a temperature gradient inside shotcrete, which affects the development of its mechanical strength. This research investigated the strength evolution of shotcrete in simulated high geothermal environment by applying a unidirectional heat source. The influence of temperature gradient on the pore structure, morphology, phase composition, and hydration degree of shotcrete was also studied. It was found that the early strength of shotcrete was improved but that the later strength was reduced in the high geothermal environment. It was attributed to the increase in harmful porosity and total porosity of the concrete caused by the high-temperature curing. Cracks and pores can be observed in the microstructure near the heat source region. Besides, the ettringite content in shotcrete was lower than that under standard curing environment and presented gradient distribution in the direction of the temperature gradient.

14

The influence of mineral additives and sands on the performance of self-compacting sand concretes

Djoual Belkacem, Kettab Ratiba Mitiche, Ghrieb Abderrahmane, Bouziani Tayeb, Zaitri Rebih

Advances in Materials Science

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2024

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Vol. 24, nr 1(79)

104--126

EN

The chosen plan for our case study is a network mixture design consisting of 21 mixtures. The application of this method has proven to be immensely useful in studying the influence of composition parameters (composite design) and the utilization of various types of mineral additives (mixture design). The application of the Design of Experiments (DOE) method, based on a statistical approach, allowed for a better understanding of the effect of formulation parameters, including the proportion of alluvial sand (75%), dune sand (25%), the total amount of sand kept at constant percentages, the dosages of brick powder, limestone filler and ceramic powder (all varying from 0 %, 20 %, 40 %, 60 %, 80 %, and 100 %), while keeping the dosage of superplasticizer and the water/binder ratio constant. This approach helped to understand the interactions between these parameters and their impact on the process. Mathematical models relating the variations of these parameters to the workability and compressive strength of such concrete mixtures have been established. The results obtained show that the workability of SCSC (expressed by slump flow and V-funnel flow) improves with the increase in the dosage of limestone filler (FC), brick powder (PB), and ceramic powder (PC), with element having a different impact, be it alone or in a combination. Moreover, they all improved the behavior of SCSC in both the fresh and hardened states. The experiment shows that increasing the proportions of FC and PC in the mixture, whether linear, binary, or ternary, leads to a significant improvement in compressive strength. Furthermore, better strength is observed in the ternary mixture at 28 days, with a strength of 43 MPa, with the following proportions (FC 70%, PB 20%, PC 10%). Finally, the result at 180 days of 48 MPa confirms the following proportions (PC 60 %, FC 30 %, PB 10 %) The compliance of some SCSC compositions was tested according to the recommendations of the French Association of Civil Engineering.

15

Influence of the shape of the copper component on the mechanical properties of the friction material used in the disc brakes

Borawski Andrzej

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 4

807--818

EN

Brakes are an important safety feature of vehicles. The materials of which the friction elements are made pose some risk to the environment. This can be a case during manufacture, operation and disposal. Any step to improve the ecology deserves thorough examination and possible introduction into production. For this reason, it has been decided to investigate whether it is possible to replace aramid with another material that is already present in its composition. The choice fell on copper, which was used in prepared samples in the form of both powder and fibers.

16

Investigation of glass fiber influence on mechanical characteristics of natural fiber reinforced poliester composites : an experimental and numerical approach

Mohapatra Deepak Kumar, Deo Chitta Ranjan, Mishra Punyapriya

Composites Theory and Practice

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2022

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R. 22, nr 3

123--129

EN

In the past few decades, natural fiber reinforced polymeric composites have gained significant importance for various structural applications in different sectors like the automotive, aerospace, sports and building construction industries. However, hybridizations make the composite more versatile in term of strength, weight and its processing for many engineering applications. In the current study, a polyester resin matrix was reinforced with two different natural fibers, namely kenaf and palmyra palm leaf stalk (PPLS) and hybridized with glass fiber. Four layers of two different fiber mats, kenaf/glass and PPLS/glass with different stacking sequences were employed to fabricated laminates by the hand lay-up technique. In this case, an attempt was made using the numerical approach to investigate the influence of glass fiber on the mechanical characteristics of the laminates. To substantiate the results of the numerical approach, experiments were conducted. Enhancement of both the tensile and flexural strength was observed due to hybridization of both the kenaf and PPLS fiber with glass fiber. The tensile and flexural strength improved by 68.91 and 37.63% respectively when the kenaf fiber was hybridized with glass fiber. Similarly, enhancement of 54.42% of the tensile strength and 15.92% of the flexural strength were noticed when the PPLS fiber was hybridized with glass fiber. Through the use of ANSYS software, finite element analysis (FEA) was employed as a simulation method to examine the tensile and flexural strength. The numerical findings were found to be quite close to the experimental results, with a variation of less than 3%.

17

Kształtowanie właściwości materiałów geopolimerowych w zależności od modułów molowych SiO2/Al2O3 oraz SiO2/Na2O

Sikora Szymon, Skowera Karol, Hynowski Mariusz, Rusin Zbigniew

Cement Wapno Beton

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2022

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R. 27, nr 2

115--125

PL

Sektor budowlany jest odpowiedzialny za około 37% światowej emisji dwutlenku węgla [CO2], do atmosfery. Z tego względu ograniczenie jego emisji oraz ograniczenie emisji innych gazów cieplarnianych, w tym sektorze, ma szczególne znaczenie wobec postępujących zmian klimatycznych. Ważne jest, aby nowe wyroby budowlane cechował mniejszy wpływ na środowisko naturalne, podczas ich całego cyklu życia, a ich produkcja została oddzielona od wykorzystania energii pierwotnej. W niniejszej pracy zbadano wybrane właściwości materiałów geopolimerowych. Geopolimery to nieorganiczne, amorficzne polimery glinokrzemianowe, które w określonych zastosowaniach mogą stanowić alternatywę dla wyrobów, zastępując cement portlandzki. W niniejszej pracy przedstawiono właściwości zapraw geopolimerowych, m.in. porowatość oraz wytrzymałość mechaniczną, w zależności od ich składu chemicznego. Ten ostatni opisany przez odpowiednie stosunki molowe tlenków SiO2/Al2O3 oraz SiO2/Na2O. Wyniki badań pokazują, iż wzrost zawartości SiO2 względem Al2O3 w mieszaninie reakcyjnej wpływa na zmniejszenie porowatości zapraw geopolimerowych. Zaprawy o dużym module molowym SiO2/Al2O3 mają zwartą i szczelną mikrostrukturę oraz wysoką wytrzymałość mechaniczną. Podobny efekt otrzymano stosując wyższe stężenia roztworu wodorotlenku sodu [NaOH], w stosunku do roztworu krzemianu sodu [Na2SiO3], w mieszaninie aktywatora w procesie geopolimeryzacji.

EN

The construction sector is responsible for around 37% of global emissions of the carbon dioxide to the atmosphere. Therefore, reducing gas emissions, in this construction sector, is particularly important, given the progressing climate change. For this reason, limiting its emissions and limiting the emission of other greenhouse gases in this sector, is of particular importance in view of the progress of climate change. It is important that new construction products have less impact on the environment during their entire life cycle, and their production has been decoupled from the use of primary energy. In this work, selected properties of geopolymeric materials were examined. Geopolymers are inorganic aluminosilicate polymers with an amorphous microstructure, which may be an alternative in certain applications, for products based on Portland cement. Here, the properties of geopolymer mortars, i.e. porosity, microstructure and mechanical strength, were compared. The influence of the composition of reaction mixture on these properties, defined by the appropriate SiO2/Al2O3 and SiO2/Na2O molar ratios, was also defined. The results show that increasing the content of SiO2 in relation to Al2O3 in the composition of the reaction mixture, reduces porosity. Thus, leading to a more compact microstructure and higher mechanical strength. A similar effect occurs when a higher NaOH solution concentration is used, in comparison to the sodium silicate [Na2SiO3] solution.

18

Review of fibers and fabrics used for special services’ protective clothing in terms of their mechanical and thermal properties

Miedzińska Danuta, Wolański Robert

Biuletyn Wojskowej Akademii Technicznej

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2022

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Vol. 71, nr 1

15--34

EN

In the paper, special clothing is understood as protective clothing used by services, in particular fire services, but also military and police, working in fire hazard conditions, where the main risk factors for the user are: a high temperature, a contact with hot objects, and a mechanical damage. The presented study deals with the review of special clothing industry and discusses cloths structure for compliance with national and European regulations. The parameters of technical fibers used for production of the above-mentioned clothes used during firefighting in open spaces, made of flame retardant yarns, e.g., aramid yarns or mixtures of flame retardant yarns, were analysed.

PL

W artykule ubrania specjalne rozumiane są jako odzież ochronna stosowana przez służby, w szczególności pożarnicze, ale także wojskowe i policyjne, pracujące w warunkach zagrożenia pożarowego, gdzie głównymi czynnikami ryzyka dla użytkownika są: wysoka temperatura, kontakt z gorącymi przedmiotami i uszkodzenia mechaniczne. W pracy dokonano rozpoznania branży produkcji ubrań specjalnych i omówiono ich budowę w odniesieniu do zgodności z przepisami krajowymi i europejskimi. analizie poddano parametry włókien technicznych służących do produkcji ww. ubrań stosowanych podczas gaszenia pożarów w przestrzeni otwartej, wykonanych z przędz trudnopalnych, np. aramidowych, lub z mieszanek przędz trudnopalnych.

19

Durability forecast of long rod composite insulators operating under variable mechanical loading conditions

Bielecki Jerzy, Wańkowicz Jacek

Archives of Electrical Engineering

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2022

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Vol. 71, nr 3

701--715

EN

Suspension line insulators are during their operation subject to static forces and variable loads, usually of a cyclic character. These variable loads have a significant impact on the mechanical durability of composite insulators. A method of providing durability forecast for composite line insulators based on fatigue characteristics has been proposed. The method allows providing durability forecast of insulators in a wide range of variable loadings, i.e. from quasi-static to high amplitude loadings.

20

Physical and mechanical properties of dune sand mortar reinforced with recycled pet fiber: an experimental study

Ghrieb Abderrahmane, Abadou Yacine

Advances in Materials Science

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2022

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Vol. 22, nr 4(74)

41--56

EN

Polyethylene terephthalate is a synthetic material known as PET. PET strapping bands is a material commonly used in all industries for packaging and bundling. The excessive use of this material has led to the pollution of the urban environment, which necessitated the search for effective solutions to dispose of this waste. The treatment and reuse of these materials is among the best solutions that contribute to reducing environmental pollution on the one hand and enabling the obtaining of economical products on the other hand. The main purpose of this experimental study is to valorize dune sand mortar and PET waste in the manufacture of cement mortar. It also aims to investigate the impact of the inclusion of recycled PET fibers on the physical and mechanical properties of the reinforced mortar. The study was carried out in several phases; after a physical and chemical characterization of the materials used, a method for the composition of mixtures was proposed, which is based on the progressive substitution of dune sand by recycled PET fibers. The quantity of cement added to each mixture is fixed at 450 g, and that of dune sand and fibers is taken as equal to 1350 g. In order to properly examine the influence of the incorporation of fibers on the properties of the reinforced mortar, the substitution rate of dune sand by the fibers varied from 0% to 2.5% with a step of 0.5%. For each mixture, many characteristics of the mortar were tested, such as consistency, bulk density, compressive strength, and flexural strength. The results obtained show that the incorporation of PET fibers has a significant effect on the fresh and hardened properties of the treated mortar.