Wyniki wyszukiwania - BazTech

1

Wpływ dodatku wapna na skład fazowy i ściśliwość mieszaniny kaolinu i popiołu lotnego

Knapik-Jajkiewicz Karolina

Inżynieria i Budownictwo

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2023

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R. 79, nr 5-6

261--266

PL

W artykule przedstawiono wyniki badań mieszanin wykonanych na bazie gruntu drobnoziarnistego z dodatkiem popiotu lotnego z fluidalnego spalania węgla w ilości 10-40% i wapna w ilosci 1-4%. Określono różnice w składzie fazowym, ściśliwości i pęcznieniu mieszanin wykonanych z udziałem i bez udziału wapna. Zauważono pozytywny wpływ wapna na uzyskane wartości maksymalnego odkształcenia objętościowego w wyniku działającego naprężenia pionowego oraz na pęcznienie mieszanin.

EN

This paper presents the tests results of mixes prepared on the basis of fine grained soil with addition of 10-40% fly ash from fluidized bed combustion and 1-4% lime. Differences in phase composition, compressibility and swelling of mixes with and without lime were determined. A positive effect of lime on the obtained values of maximum volume strains upon an acting stress was observed, as well as reduction of swelling in soil-fly ash mixes with lime.

2

Multi-state approach to food packaging material quality and consumption safety analysis

Bogalecka Magdalena, Morawska Magda

Safety and Reliability of Systems and Processes

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2022

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Summer Safety and Reliability Seminar 2022

35--50

EN

The food packaging material and its quality assessment based on permeability, tensile strength, swelling, transmittance, and biofilm formation are discussed in this chapter. The semi-Markov model of food packaging material quality change process is introduced and its characteristics are determined. Next, the safety and resilience indicators are proposed for multi-state analysis, identification, prediction and optimization of packaged food product consumption safety.

3

Zagrożenia związane z głębokim posadawianiem budowli w obrębie iłów mioceńskich występujących w podłożu Krakowa

Czurczak Jakub, Kaczmarczyk Robert, Czurczak Marta

Przegląd Geologiczny

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2022

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Vol. 70, nr 8

581--589

EN

The constant development of large urban centres such as Kraków causes a demand for residential and industrial space, which is difficult to meet. This forces the necessity to implement further construction investments in difficult soil and water conditions. Due to the limitations resulting from the relatively small area possible for development, multi-level underground floors are designed more and more often. The foundation of additional risks, which, if not taken into account, may lead to damage to buildings. The purpose of the article is to characterize the risks involved with the placement of objects on Miocene clay layers in terms of their tendency to volumetric changes, swelling and shrinkage. The threats are presented using the example of selected buildings in Kraków, which were founded within the clay and then failed for various reasons. Additionally, the article presents the results of laboratory tests of Miocene clays from various locations within the city of Kraków.

4

Wybrane właściwości fizykomechaniczne mieszanek kruszywowo-bentonitowych

Pytlowany Tomasz, Chmielowski Krzysztof, Skrzypczak Izabela, Studziński Andrzej, Bacewicz Daniel

Materiały Budowlane

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2022

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nr 11

165--167

PL

Mieszanki kruszywowo-bentonitowe są coraz powszechniej stosowanym rozwiązaniem do stabilizacji oraz uszczelnienia obiektów w inżynierii środowiska i budownictwie, np. składowiska, wały przeciwpowodziowe, zapory ziemne, torowiska drogowe czy kolejowe, a także różnego rodzaju obiekty kubaturowe. W artykule przedstawiono wyniki wybranych badań właściwości fizykomechanicznych mieszanek na bazie wybranego kruszywa i bentonitu. Przeprowadzone badania wykazały, że mieszanki kruszywowo-bentonitowe można uznać za przydatne w budownictwie, m.in. do stabilizacji wykopów.

EN

Aggregate-bentonite mixtures are an increasingly widely used solution for stabilization and sealing of both environmental and construction engineering facilities, e.g. landfills, flood embankments, earth dams, road and railway tracks, as well as various types of cubature structures. The article presents the results of selected studies of the physical and mechanical properties of mixtures developed in various proportions based on aggregate and bentonite. The conducted research has shown that the aggregate-bentonite mixtures in question can be considered useful in construction, e.g. for the stabilization of excavations.

5

Enhancement of mechanical properties of concrete using microwave cured bamboo composites

Adeniyi Ajayi Joseph, Gana James, Adanikin Ariyo, Ogedengbe Kola, Idowu Abundance

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

553--567

EN

Microwave curing of bamboo fiber increases the physical and mechanical qualities of cement concrete, according to previous studies. However, there are limited research on their endurance when used as an additive in concrete manufacturing to increase strength. The impact of bamboo fiber and Styrene Butadiene Rubber (SBR) on the mechanical and microstructure of the resulting concrete is investigated in this study. With the inclusion of bamboo fiber ranging from 0-1.5%, a mix ratio of 1:1.5:3 was used. To make the samples, 10% SBR by weight of cement was dissolved in the mixing water. The batching was done by weight, with a water cement ratio of 0.6. Compressive strength, water absorption, swelling, modulus of elasticity, and modulus of rupture were all studied as mechanical properties. Various characterization tests such as SEM, EDS, FTIR, XRD, and TGA were performed on the microstructure, crystalline nature, and mineral composition of certain samples. According to the FTIR study’s findings, peak levels were detected in the O-H stretching, C-H fiber and CH2 functional groups, carbonyl group, C-O and C-C functional groups. As the temperature climbed, TGA measurements showed a drop in weight. The XRD test revealed peak levels of 6.611, 4.255, and 3.855 for sanidine, quartz, and calcite, respectively. After 28 days, the inclusion of bamboo fibers as an additive in concrete shows some promising outcomes in compressive strength, with samples containing 1% and 1.5% bamboo fiber cured at 80°C having a higher compressive strength value.

6

Effects of hydrocarbon contamination on the engineering geological properties of Neogene clays and Pleistocene glacial tills from Central Poland

Dobak Paweł, Izdebska-Mucha Dorota, Stajszczak Piotr, Wójcik Emilia, Kiełbasiński Kamil, Gawriuczenkow Ireneusz, Szczepański Tomasz, Zawrzykraj Piotr, Bąkowska Anna

Acta Geologica Polonica

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2022

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Vol. 72, no. 4

529--555

EN

Petroleum products influence the engineering behaviour of the soil. Neogene clays and glacial tills from Central Poland were tested under laboratory conditions to evaluate the changes of selected physical and mechanical parameters: particle size distribution, particle density, swelling, shear strength and permeability. Four petroleum products were used in the experiments: diesel fuel, kerosene, jet fuel and mineral engine oil. The study revealed that even for the lowest degree of contamination the values of physical and mechanical properties of the soils changed significantly. Greater variation can be expected in soils contaminated with high-viscosity compounds. Also, higher relative changes were found for glacial tills than for Neogene clays. Consolidation tests revealed changes in soil permeability depending on the soil composition and the physical properties of the contaminant – considerable reduction of permeability was observed for glacial tills contaminated with light Jet fuel, while the reduction was lower for Neogene clays. The obtained results indicate the role of mesopores and the dimensionless pore pressure coefficient in changes of soil permeability. The methodological issues regarding testing and analysing the hydrocarbon-contaminated soils were also presented and discussed, which might be useful for researchers studying contaminated soils.

7

Gas Formation Reactions in the Raw Mixture Based on TPP Ash

Koshlak Hanna

Rocznik Ochrona Środowiska

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2021

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Tom 23

106--116

EN

The article discusses the physicochemical mechanisms of the effect of chemical reagents on the processes of swelling of the raw mixture based on the ash of thermal power plants. The process of structure formation in such mixtures occurs as a result of physicochemical transformations of its constituent components. To intensify gas evolution and obtain materials of a porous structure, the presence of a gas former is necessary. The author has analysed the possibility of creating a porous structure in a raw mixture based on ash with the introduction of various gas formers or their formation as a result of exchange reactions. The main chemical compounds contributing to pore formation have been determined. To form a given structure, it is proposed to control chemical transformations at the stage of swelling. To study the processes of intensification of gas evolution, the author proposes to investigate the mechanisms of the influence of mineral fillers and chemical reagents on swelling processes based on the analysis of the Gibbs equation. The parameters of the Gibbs equation are obtained, by which it is possible to determine the probability of the occurrence of chemical reactions with the proposed chemical agents for the formation of gas bubbles with (pores) in the raw material.

8

Zmiany właściwości gruntu w strefie aktywnej pęcznienia

Wszędyrówny-Nast Małgorzata, Tymiński Wojciech

Przegląd Geologiczny

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2021

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Vol. 69, nr 12

917--924

EN

Swelling is a phenomenon which occurs in high plasticity soils. It is observed immediately after the contact of not fully saturated expansive soil with water. In clays of very small coefficient of permeability, it may be concluded that swelling is a surface phenomenon - water does not need to infiltrate deep into the clay layer for swelling to start. The so-called active-wetting zone may be observed in the soil layer where the swelling process takes place. The soil conditions in the zone change during swelling and consequently result in changes in the soil strength and deformation properties. In the paper the results of swelling pressure tests are presented and analysed. The tests were carried out in oedometers. Based on the test results, the range of the active-wetting zone in the tested samples was analysed, taking into account index properties of tested soils, as well as orientation of tested samples.

9

The influence of electron and gamma irradiation on the properties of starch : PVA films : the effect of irradiation dose

Cieśla Krystyna A., Abramowska Anna

Nukleonika

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2021

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Vol. 66, No. 1

3--9

EN

The paper discusses the effect of ionizing radiation on the functional properties of the biodegradable starch:PVA films. The analysis is related to the possible use of the material for packing the products (particularly, food) that are predicted for radiation decontamination and to the potential modifi cation of the material by radiation treatment. Our previous results have shown that the infl uence of ionizing radiation on the films’ properties varied for the specific compositions (differing in starch:PVA ratio or the type of substrates) and depended on irradiation conditions. However, these studies considered only the irradiation performed in gamma chamber or in e-beam using a dose of 25 kGy. Therefore, the present study deals with the effect of the irradiations performed using various doses on the selected promising starch:PVA composition. The films characterized by starch:PVA weight ratio of 45:55 was obtained by solution casting and irradiated with fast electrons in air and with 60Co gamma rays in nitrogen applying the doses of 5, 10, 20, 25, 30, 50, and 75 kGy. No regular dependence has been noticed between the composition of films (differing in the starch and PVA content) and the intensities of the particular bands in the UV-VIS DRS spectra after irradiation. The results indicated strong interaction of the starch and PVA components in the films and the occurrence of specific reactions in each composition upon irradiation. No special differences were observed between tensile strength and Young’s modulus of the non-irradiated films characterized by the starch:PVA ratio equal to 45:55 and the samples irradiated using doses in the range of 5–75 kGy. Similarly, no differences were observed in both cases between the swelling capability of the non-irradiated and the irradiated films. However, it can be deduced that solubility in water increased when the radiation dose increased. The results show that using the doses till the range 25 kGy does not cause an essential change of all the examined properties of the starch:PVA (45:55) films. Accordingly, starch:PVA (45:55) films might be considered suitable for packing food predicted for radiation decontamination.

10

Experimental and finite element analysis of slope stability treated by lime milk (case of El Amir Abdelkader embankment)

Belabbaci Zeyneb, Berrabah Amina, Bouri Djamel Eddine

Mechanics and Mechanical Engineering

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2021

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Vol. 25, nr 1

77--83

EN

This paper presents an experimental stabilization approach of the landslide that threatens a slope located near the city of El Amir Abdelkader, Ain Temouchent, Algeria. Stabilization is assured by the addition of lime milk, and then a numerical validation of the results with respect to the safety coefficient before and after treatment was performer by “Plaxis” software. Experimental results show that the stabilization by lime milk improves compaction parameters, swelling and shear strength, particularly the cohesion and friction angle, the latter permitting appreciation of the sliding surface on which it is necessary to base the calculation of the safety coefficient before and after treatment. Numerical results indicate that the factor of safety increases with the improvement of the mechanical characteristics c and φ, which are improved by increasing lime milk percentage. The numerical validation using “Plaxis” finite element code gives results that are in perfect agreement with the experimental ones, indicating that this software is a good tool for slope stability study.

11

Numerical Modeling of the Pipeline Uplift Mechanism in Clay

Abdelfateh Kattar, Mohamed Baheddi, Fattah Mohammed Yousif

Archives of Hydro-Engineering and Environmental Mechanics

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2021

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Vol. 68, nr 2

119--135

EN

Buried pipelines are a vital infrastructure and are mainly used to transport energy carriers and other essential products. The pipes are generally buried in the upper layer of soil deposits and, therefore, are highly affected by different geo-environmental conditions. The various pathological cases recorded in the world are caused by the degradation of structures in contact with swelling soils, the fact that necessitates a full understanding and investigation of such a phenomenon. This paper presents a method for the pipeline behavior modeling based on the finite element analysis by using PLAXIS 3D software, aimed at the determination of the pipe bending moment, displacement over its length, and the evaluation of vertical stresses in soil under the pipe. A parametric study has been carried out to investigate the effect of the pipe burial depth and the soil cohesion. The finite-element results have been compared with experimental data from the literature. It was found that, unlike laboratory models, the numerical analysis can account for the internal pressure in the pipe and the depth of the pipe burial. The finite-element analysis showed that the presence of fluid pressure inside the pipe results in a decrease in the maximum swelling of the soil by about 95%. The displacement of the pipe is considerably affected by the burial depth. The vertical stress at one end of the pipe can be greater than that at the other end in the case of a pipe under internal pressure, while in the case of an empty pipe, the values are very close at both ends. The numerical analysis shows that an increase in the pipe internal pressure leads to a decrease in its vertical displacement.

12

Moisture swelling and shrinkage of pine wood versus susceptibility to robotic assembly of furniture elements

Turbański Wojciech, Sydor Maciej, Matwiej Łukasz, Wiaderek Krzysztof

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2021

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No. 115

63--71

EN

Moisture swelling and shrinkage of pine wood and susceptibility to robotic assembly of furniture elements. Background and Objectives. Processing technology, storage conditions and wood properties affect the actual dimensions of wooden elements. It was decided to experimentally check how the dimensions of samples, made of the selected wood species, will change under the influence of different storage conditions, typical for industrial environments. And especially how these changes will affect the susceptibility to assembly of upholstery frame rails that form a box joint. Materials and Methods. The tests were performed on three series of rails made of Scotch pine wood. Each tested series consisted of 12 elements. First, the five dimensions forming the box joint were measured. Then, each series was exposed to different conditions: in the industrial hall (air of RH = 29-48% and t = 16-24°C), in the compressor room (RH = 24-51%, t = 13-27°C) and outside in a covered shed (RH = 20-50%, t = 3-23°C). After 35 days the dimensions were measured again. Results. It was found that the average moisture content decreased and the dimensional deviations increased in the samples stored in the production hall and in the compressor room. In samples stored outside, the mean moisture content did not change, but the dimensional deviations increased significantly. Discussion. The storage of wooden elements increases the deviations from assigned dimensions. Exposure to repeated changes in moisture content and ambient temperature, even without changing the final moisture content of the elements, results in greater dimensional changes than storage under more stabilized conditions that reduce wood moisture content. Conclusions. The shrinkage and swelling of wood due to changes in its moisture content are not fully reversible, therefore, apart from maintaining the appropriate temperature and air humidity during storage, it is important to keep these conditions unchanged.

PL

Pęcznienie i kurczenie się drewna sosnowego a podatność na zrobotyzowany montaż elementów mebli. Wprowadzenie. Technologia obróbki, warunki przechowywania i właściwości drewna wpływają na rzeczywiste wymiary elementów drewnianych. Postanowiono eksperymentalnie sprawdzić jak zmienią się wymiary próbek, wykonanych z wybranego gatunku drewna pod wpływem różnych warunków przechowywania, typowych dla środowisk przemysłowych. A zwłaszcza jak te zmiany wpłyną na podatność na zrobotyzowany montaż ramiaków ram tapicerskich, tworzących połączenie wielowpustowe. Materiały i metody. Badania przeprowadzono na trzech seriach ramiaków z drewna sosny zwyczajnej. Każda testowana seria składała się z 12 elementów. Najpierw zmierzono pięć wymiarów tworzących połączenie wpustowe. Następnie każda seria została wystawiona na inne warunki: przechowywanie w hali przemysłowej (powietrze o wilgotności względnej 29-48% i temperaturze 16-24°C), w sprężarkowni (RH = 24-51%, t = 13-27 °C) i na zewnątrz w zadaszonej wiacie (RH =20-50%, t = 3-23°C). Po 35 dniach ponownie zmierzono te same wymiary ramiaków. Wyniki. Stwierdzono zmniejszenie średniej wilgotności oraz niewielkie zwiększenie odchyłek wymiarowych w próbkach przechowywanych w hali produkcyjnej i w sprężarkowni. W próbkach przechowywanych na zewnątrz średnia wilgotność nie zmieniła się, ale znacznie zwiększyły się odchyłki wymiarowe. Dyskusja. W analizowanych warunkach składowanie elementów drewnianych w każdym przypadku zwiększa odchyłki od wymiarów nominalnych. Narażenie na powtarzające się zmiany wilgotności i temperatury otoczenia, nawet bez zmiany końcowej wilgotności elementów, powoduje większe zmiany wymiarów niż przechowywanie w bardziej ustabilizowanych warunkach, które zmniejszają wilgotność drewna. Wnioski. Skurcz i pęcznienie drewna pod wpływem zmian jego wilgotności nie są w pełni odwracalne, dlatego oprócz zapewnienia właściwych temperatury i wilgotności powietrza przy przechowywaniu, ważne jest zachowanie niezmienności tych warunków.

13

Impact of annual growth pattern on swelling of selected wood species

Doborowolska Ewa, Macińska Joanna

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2021

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No. 115

116--125

EN

Impact of annual growth pattern on swelling of selected wood species. Unit swelling was investigated in radial and tangential directions as well as in the intermediate directions for wood of density ranging from 300÷500 kg/m3 and 500÷700 kg/m3 and above 700 kg/m3. Species selected included pine – PNSY (Pinus sylvestris L.), oak – QCXE (Quercus. robur L.) and bangkirai – SHBL (Shorea spp.), teak – TEGR (Tectona grandis), merbau – INXX (Intsia bijuga), jatoba – HYCB (Hymenaea courbaril L). For all the studied wood species, the lowest swelling in the radial direction (0°) was found after both 2 h and 24 h of wetting in water, which increased with the angle of inclination of the annual growth and, after reaching 90°, corresponded to the maximum swelling in the tangential direction. For pine (PNSY) sapwood and heartwood and for oak (QCXE), a high swelling unit was obtained after a wetting time of 2 h, with little change after 24 h of wetting. Swelling increments for the other wood species were lower, ranging from 1% to over 2% after a wetting time of 2 h, showing slight differences between radial and tangential directions. For these wood species, after 24 h of wetting the swelling was higher and varied from more than 2% to nearly 5% in the radial direction and from more than 4% to 10% in the tangential direction. The study showed that, for high-density wood species, it becomes necessary to extend the wetting time in order to determine the actual maximum swelling per unit. The swelling anisotropy coefficients ε of the studied wood species corresponded to the values found in the literature. Higher coefficients were found for oak (QCXE) and teak (TEGR), bangkirai (SHBL) and jatoba (INXX), and were related to the characteristic features of the density structure and anatomical structure. The unit swelling values calculated with the Krzysik (1974) and Vorreiter (1949) equations may be used to assess changes in the dimensions of elements in intermediate directions. The discrepancies between the experimental and theoretical values are smaller for the unit swelling values calculated with the Vorreiter (1949) equation compared to the Krzysik (1974) equation.

PL

Wpływ układu słojów rocznych na spęcznienie wybranych gatunków drewna. Zbadano spęcznienie jednostkowe w kierunku promieniowym i stycznym drewna o gęstości, zawierającej się w trzech przedziałach 300÷500 kg/m3 i 500÷700 kg/m3 oraz powyżej 700 kg/m3, do których należały sosna – PNSY (Pinus sylvestris L.), dąb – QCXE (Quercus. robur L.) oraz bangkirai – SHBL (Shorea spp.), teak – TEGR (Tectona grandis), merbau – INXX (Intsia bijuga), jatoba – HYCB (Hymenaea courbaril L). Dla wszystkich badanych gatunków drewna stwierdzono, najniższe spęcznienie w kierunku promieniowym (0°) zarówno po 2 h i 24 h nawilżania w wodzie, które rosło wraz z kątem nachylenia przyrostów rocznych i po osiągnięciu 90°, odpowiadającemu kierunkowi stycznemu, osiągnęło maksymalna wartość. W przypadku drewna sosny (PNSY) biel i twardziel oraz drewna dębu (QCXE) po czasie nawilżania równym 2 h uzyskano maksymalne spęcznienie jednostkowe, niezmieniające się po 24 h nawilżania. Przyrosty spęcznienia dla pozostałych gatunków drewna były niższe i po czasie nawilżania 2 h wynosiły od 1% do ponad 2%, wykazując nieznaczne różnice między kierunkami promieniowym i stycznym. Po 24 h nawilżania spęcznienie było wyższe i w kierunku promieniowym wahało się od ponad 2% do blisko 5% a w kierunku stycznym od ponad 4% do 10%. W przypadku drewna o wysokiej gęstości wydaje się konieczne wydłużenie czasu nawilżania, który pozwoli na ustalenie rzeczywistego maksymalnego spęcznienia jednostkowego. Współczynniki anizotropii spęcznienia α badanych gatunków drewna odpowiadają wartościom zawartym w literaturze przedmiotu. Wyższe współczynniki wykazały dąb (QCXE) i teak (TEGR), bangkirai (SHBL) i jatoba (INXX), związane z charakterystycznymi cechami struktury gęstości i budowy anatomicznej. Obliczone równaniami Krzysika (1974) i Vorreiter (1949) wartości spęcznienia jednostkowego mogą służyć do oceny zmian wymiarów elementów w kierunkach pośrednich, powstałych w wyniku nawilżania. Mniejsze rozbieżności między wartościami eksperymentalnymi i teoretycznymi wykazują spęcznienie jednostkowe obliczone równaniem Vorreitera (1949) w porównaniu z równaniem Krzysika (1974).

14

Volumetric behavior of natural swelling soil on drying-wetting paths. Application to the Boumagueur marl -Algeria-

Mebarki Mehdi, Kareche Toufik, Benyahia Sabah, Derfouf Feth-Ellah Mounir, Abou-Bekr Nabil, Taibi Said

Studia Geotechnica et Mechanica

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2020

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Vol. 42, nr 3

248--262

EN

This article presents the results of experimental work carried out both in situ (coring; pressuremeter test) and in the laboratory (drying-wetting and oedometric tests) to describe the volumetric behavior on drying-wetting path of a swelling clayey soil of eastern Algeria. In order to perform drying-wetting tests the osmotic technique and saturated salts solutions were used. These suction-imposed methods have gained widespread acceptance as reliable methods for imposing suction on soil specimens. They allowed to sweep a wide range of suctions between 0 and 500 MPa. The ability to impose suction on soil specimens allows for drying and wetting stress paths to be applied to evaluate resulting changes in state parameters (void ratio, degree of saturation and water content). These paths were carried out on specimens with different initial states. Slurries of soil were used to characterize the reference behavior, while the undisturbed soil samples allow to describe the behavior of material under in situ conditions. In the last part of this article and to specify the behavior observed in the saturated domain, a comparison between the resulting deformations of the drying-wetting test and those resulting from the oedometric test was made.

15

Heave analysis of shallow foundations founded in swelling clayey soil at N’Gaous city in Algeria

Khennouf Abdelaziz, Baheddi Mohamed

Studia Geotechnica et Mechanica

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2020

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Vol. 42, nr 3

210--221

EN

The design of shallow foundations on swelling soils needs a thorough study to evaluate the effect of swelling potential soil on the final foundation heave. For this reason, a simple analytical approach based on the soil stress state under the foundation can be used to calculate the foundation heave. This paper reports a set of analytical and numerical analysis using the finite-difference code (FLAC 3D), performed on an isolated shallow foundation founded on a swelling soil mass at N’Gaous city in Batna Province, Algeria, subjected to distributed vertical loads. Further, the influence of some parameters on total heave was analyzed, such as the embedded foundation and soil stiffness. The analysis results from the proposed 3D modelling was compared and discussed with analytical results. The numerical results obtained show a good agreement with the analytical solutions based on oedometer tests proposed in the literature, and deliver a satisfactory prediction of the heave of the shallow foundations.

16

Swelling and water resistance of black poplar wood (Populus nigra L.) modified by polymerisation in lumen with styrene

Żmuda Emil, Radomski Andrzej

Annals of Warsaw University of Life Sciences - SGGW. Forestry and Wood Technology

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2020

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No. 110

35--40

EN

Swelling and water resistance of black poplar wood (Populus nigra L.) modified by polymerisation in lumen with styrene. Polymerisation in lumen of black poplar (Populus nigra L.) was performed to improve wood properties related to interaction with water. Wood samples were modified with styrene or a mixture of styrene and maleic anhydride, using benzoyl peroxide as initiator. Polymerisation was conducted in closed vessels at a temperature up to 120 °C. Volume swelling and water absorbability of modified wood samples were measured. A significant decrease in the rate of water absorption was found, especially at the initial stage of soaking, resulting in 50 % decrease in volume swelling and 85 % decrease in water absorption.

PL

Pęcznienie i nasiąkliwość topoli czarnej (Populus nigra L.) modyfikowanej styrenem metodą polimeryzacji w świetle komórki. Polimeryzacje w świetle komórki wykonano na gatunku topoli czarnej (Populus nigra L.) w celu poprawy jej właściwości związanych z oddziaływaniem woda-drewno. Próbki drewna zostały zmodyfikowane styrenem oraz mieszaniną styrenu i bezwodnika kwasu maleinowego z dodatkiem nadtlenku benzoilu, jako inicjatora. Następnie próbki poddano polimeryzacji w zamkniętych pojemnikach w warunkach podwyższonej temperatury do 120°C w celu utwardzenia. Na wykonanych próbkach zostały przeprowadzone następujące badania: WPG, spęcznienia objętościowego i nasiąkliwości. Pęcznienie objętościowe zmniejszyło częściowo swoje wartości. Stwierdzono znaczne zmniejszenie szybkości wchłaniania wody, zwłaszcza w początkowej fazie namaczania, co skutkowało 50% zmniejszeniem spęcznienia objętościowego i 85% spadkiem nasiąkliwości.

17

Microstructure and geotechnical characteristics of a highly plastic clay treated by magnesium chloride

Bahloul Ouassila, Abbeche Khelifa, Bahloul Azzedine

Mining Science

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2019

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Vol. 26

249--262

EN

Chemical stabilization of soil is an effective improvement technique because it reduces the ability of the soil to swell. We added different proportions of magnesium chloride to an expansive clay and performed swelling, geotechnical characterization, and mechanical strength tests. The results show that the swelling potential and swelling pressure of the expansive soil were significantly decreased by the addition of magnesium chloride (MgCl2). This treatment also improved the physical and mechanical characteristics and microstructure of the soil. The soil's plastic limit, shrinkage limit, cohesion, and internal friction angle all increased linearly with the addition of the MgCl2 stabilizer. However, we observed that the liquid limit of the soil decreased as the level of magnesium chloride was increased.

18

CO2 - CH4 sorption induced swelling of gas shales: An experimental study on the Silurian shales from the Baltic Basin, Poland

Miedzińska D., Lutyński M.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 2

415--427

EN

The main aim of the research presented in the paper was to study the phenomena of shale swelling induced by CH4 and CO2 sorption. In the study, a Silurian gas shale sample from the Baltic Basin in Poland was used. Samples represented typical characteristic features of polish shale gas formations with relatively low total organic carbon (0.8%) and high clay mineral content. The first part of the study was devoted to competitive adsorption of CO2 and CH4. The second part was devoted to observation of the sorption induced swelling phenomena, where sample linear strains were monitored with the use of strain gauges. Swelling tests were conducted up to the pressure of approximately 8 MPa with CO2, CH4 and helium as the baseline. Experimental results were compared with the Seidle and Huitt model where Langmuir constants where determined with volumetric sorption tests. Results of the study showed that matrix swelling in case of CO2 adsorption was greater than in the case of CH4 adsorption. The swelling value was directly proportional to adsorption and was about 5 to 10 times smaller than in the case of coal. Sorption of methane and carbon dioxide in the gas-bearing shale was about 10-times lower than in hard coals. The Seidle and Huitt model developed for coals was equally suitable to describe the processes of shale swelling.

19

Wpływ zanieczyszczeń kruszywa na trwałość posadzek betonowych

Fyall Z., Wysocki L.

Materiały Budowlane

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2018

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nr 9

4--6

PL

W artykule omówiono wpływ zanieczyszczeń kruszywa na trwałość posadzek betonowych. Badano zanieczyszczenia ziarnami, które w pewnych warunkach mogą powodować uszkodzenia posadzki spowodowane ich pęcznieniem. Na podstawie analizy uszkodzeń sformułowano zalecenia dotyczące ograniczenia takich uszkodzeń.

EN

The paper presents the impact of aggregate contamination on the durability of concrete floors. There were investigated grains impurities which under certain conditions cause damages to the floor surface due to their expansion. On the basis of the analysis of damages recommendations in order to limit such damages were been formulated.

20

Porous structures and their effect on thermophysical properties of thermal protection elements

Pavlenko A. M., Cheilytko A., Ilin S.

Journal of New Technologies in Environmental Science

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2018

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Vol. 2, nr 3

125--133

EN

The improvement of the thermal insulating material thermophysical characteristics of the thermal protection elements by studying the porous structure is a promising direction of research. The article describes the effects of the porosity and coupling of the porous structure on the thermophysical characteristics of thermal insulating materials. The article uses standard systematized techniques and instruments of scientific research applied in thermophysics. The research methodology of highly-porous material thermophysical properties is based on performance of empirical laboratory investigations of the samples obtained.