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EN
With the gradual scarcity of high-quality sand and gravel resources, the increasing mud content in concrete aggregates could strongly adsorb on polycarboxylate superplasticizers (PCE), greatly reducing their working performance. Modifying the molecular structure of PCE or compounding sacrificial agents can effectively improve the tolerance to clay minerals. In this article, using different small molecule polyols and polypropylene glycol (PPG) as examples, density functional theory (DFT) was employed to simulate the adsorption between clay minerals and hydration products. This exploration aims to further understand the anti-clay performance of various sacrificial agents from the perspective of adsorption energy. Ca-montmorillonite (CaMMT) exhibits the lowest adsorption energy among different clay minerals, making it the preferred site for sacrificial agent adsorption. With an increase in hydroxyl number, the adsorption energy between polyol sacrificial agents and montmorillonite decreases. Among polymeric polyols, the adsorption energy between PPG 600 and montmorillonite is the lowest (-10.86 eV), indicating superior anti-clay performance by preferentially occupying active sites on montmorillonite. As the interlayer spacing of montmorillonite increases, the adsorption energy between PPG 600 and montmorillonite initially decreases and then increases, reaching the lowest value at c=15.5 Å. There are more electron transfers (0.858) compared to the electron gain and loss, confirming more interaction between the sacrificial agents and montmorillonite at 15.5Å. This article also provides a crucial theoretical basis for the structural design of anti-clay sacrificial agents, offering insights into addressing compatibility issues between PCEs and clay minerals.
3
Content available remote Physical and mechanical tests of clay plasters
EN
The main objective of this study was to test the water resistance of clay plaster and modified plaster, while ensuring performance properties such as adhesion and vapour permeability. Four types of specimens were prepared for testing: a control specimen of clay plaster, a plaster with an admixture of a hydrophobizing agent and water-glass. The last samples, where part of the clay plaster was replaced with hydrated lime. The best results were obtained for the admixture of the hydrophobizing agent.
PL
Głównym celem badań było określenie wodoodporności tynków glinianych i modyfikowanych, przy jednoczesnym zapewnieniu właściwości użytkowych, takich jak przyczepność i paroprzepuszczalność. Do badań przygotowano cztery rodzaje próbek: kontrolną z tynku glinianego, tynk z domieszką środka hydrofobizującego oraz tynk ze szkłem wodnym. W ostatnich próbkach część tynku glinianego zastąpiono wapnem hydratyzowanym. Najlepsze wyniki uzyskano przy domieszce środka hydrofobizującego.
EN
This study aimed to investigate the potential for widespread application of clay in the purification of water polluted with pesticides and water management through the absorption and desorption of dimethoate and methomyl in the natural clay of Brari (Tirana). While the maximum adsorption of methomyl on Brari clay was reached in 12 hours, the maximum adsorption of dimethoate on Brari clay was reached in 48 hours. To compare the adsorption of methomyl and dimethoate on Brari clay, their water degradation time was also taken into account. Dimethoate dissolves quickly; a contact period of 1–2 hours is sufficient to desorb 81.2% of the material. Dimethoate dissolves in water at 25 °C and has a half-life t1/2 = 30 days. Methomyl is desorbed even faster; in just two hours, 96.2% of the material is desorbed. At 25 °C, dimethoate has a half-life of t1/2 = 14 days and a high solubility of 58 g/L in water. Because methomyl and dimethoate bind poorly to clay, they can contaminate surface and groundwater.
EN
In the present study, micromechanical modeling techniques were employed to examine the mechanical properties of a hemp/clay composite material. This composite consists of hemp fibers incorporated into a clay matrix, a configuration chosen in response to environmental considerations and the natural advantages of hemp fibers, which include their lightweight nature and their considerable strength and stiffness relative to their weight. The approach adopted incorporates both localization and homogenization methodologies along with the three-phase model to provide an in-depth analysis of the composite's behavior. The findings from this theoretical model show a promising correlation with empirical data, demonstrating the model's efficacy in capturing the composite's mechanical response.
6
EN
The effect of the degree of consolidation and the stress path on the behaviour of remoulded Fujinomori clay for drained triaxial compression and extension was analysed using the Frictional State Concept. It is shown that the stress–dilatancy behaviour can be approximated by a linear general dilatancy equation given by the critical frictional state angle and two soil parameters. The newly formulated dilatant failure state is represented on the stress ratio plastic dilatancy plane by points lying on the friction state line defined by the friction state angle and the Friction State Concept parameters α=0 and β=1. It has been shown that the stress ratio–plastic dilatancy relationship, which is very rarely used in the interpretation of test results, is important for a complete description of the behaviour of soils during shearing.
EN
In this article, the effects of environmental acidity on the mechanical and volumetric properties of cement-stabilized clay soils have been investigated through various tests on experimental scale. In this study, a problematic clay was chemically stabilized by cement under three treatment conditions including short term, medium term, and long term with different conditions varying from acid to alkaline environments, which were tested by different methods to evaluate their mechanical and volumetric behavior and properties. Mechanical characteristics assessment tests in this study include compaction tests, and unconfined compressive strength, which was conducted on samples under different conditions in terms of acidity and treatment time. The results of the study indicated that soil improvement by cement increases the mechanical strength and decreases the rate of soil swelling over time and treatment duration. However, the degree of acidity of the environment affects the chemical reactions of soil and cement, especially cement hydration, which causes changes in soil strength and volume variation due to swelling.
EN
In this paper, the finite element method (FEM) is applied to calculate the bearing capacity of two footings having the aspect ratio L/B (where L and B are the length and width of the footing, respectively) equal to 1, 2 resting on one-layer and two-layer soil. Soil profile contains two soil types including sand and clay. The soil strip is 500mm × 500mm × 350mm; however, only a quarter of the model (250mm × 250mm × 350mm) is examined in the study. Two primary situations are investigated in this study. In the first situation, the one-layer system is supposed to be sandy soil with footing overlays on medium-dense sand. The soft clay/stabilized clayey layer is supposed to be on top of the sandy soil in the second condition, with the footing resting on top of the soft clay/stabilized clay. The influence of layer thickness, aspect ratio, and material property on the bearing capacity value and footing failure mechanism is studied for eight different combinations of layered soil. The bearing capacity for a one-layer case is also estimated, and it agrees well with Vesic (1973), Hansen (1970), and Terzaghi's (1943) equations. The bearing capacity of footings is observed to decline when the height of unstabilized clayey soil increases, and it increases when clayey soil is stabilized with molasses, waste foundry sand, and lime alone and in combination with each other.
10
Content available Clay/nanocomposite hydrogels : In review
EN
The development of advanced materials those are stronger, more rigid, lighter, hotter and self-renewable than existing materials has been the rising point of many research studies conducted in recent years. Within this scope, the interest to production of nanostructured materials is received considerable attention worldwide due to their potential positive contribution to wide variety of technological areas such as electronics, catalysis, adsorbents, ceramics, magnetic data storage, structural components etc. In these efforts polymer nanocomposites as the form of hydrogels, reinforced with well-dispersed layered silicate, typically montmorillonite can be given as a one of the promising composite material. However, long-standing problems for polymer-clay nanocomposites include actual exfoliation of clay particles in discrete layers, uniform distribution of clay layers throughout the polymer, and randomness of clay sequences. For the exfoliation of clay particles, although the chemical modification of clay minerals in aqueous media is the well-known and more general way applied by researchers, the physical pathway method performed by high-energy ball mills is also gaining increasing attention as an alternative pretreatment way. Grinding of crushed materials is one of the key processes in the mineral and cement industry, but the increased concern on the preparation of fine-grained powders (nano powders) or the manufacture of composites with desirable properties, especially performed with use of high-energy ball mills, has led to significantly widen the usage field of grinding. Undoubtedly, the main reason for these efforts is to improve the performance of existing materials. In this paper the fundamental concepts, classification, physical and chemical characteristics and the production methods of clay/polymer nanocomposites was briefly reviewed base on the composite hydrogel. Particular attention was paid to the pre-treatment (exfoliation) of clays with high-energy ball mills, which is increasingly being accepted as an alternative method to eliminate the negative effects of chemical treatment in some composite forms.
EN
The primary purpose of this research was the study of two natural clays Dardha (Korçë), which is located at 40°31'16.59'' N and 20°49'33.69'' E and the clay of Brari (Tirana), 41°21'14.49'' N and 19°50'17.74'' E for the removal of dimethoate, in order to clean the waters polluted with this pesticide. During the Clay-water+dimethoate contact time from 0 to 24 hours, there was spontaneous hydrolysis of dimethoate, which also theoretical data accurately explains this phenomenon. Clay-water+dimethoate contact time longer than 120 hours are not of interest for this study, because after this time there is no adsorption of dimethoate. Our experimental study focused on contact times from 24 to 120 hours. The adsorption process of dimethoate with concentrations of 0.2 mg/mL was studied; 0.3 mg/mL and 0.5 mg/mL in the natural clays of Dardhe and Brari. The desorption process of dimethoate from these clays was also studied. The desorption process was fast, where in the first two hours of contact 80 to 95% dimethoate was desorbed.
EN
This study focuses on the physical and chemical properties of soils and their geographical distribution, with a specific focus on red clay. The inverse distance weighting (IDW) technique, integrated with Geographic Information Systems (GIS), was employed to predict the chemical characteristics of the soil. Sampling was conducted at twenty-one locations in three areas: Bor Mountain, Jambor, and Kirkuk Hills, all located within Kirkuk City. Seven soil properties were examined: acidity, organic matter content, total dissolved salts (TDS), gypsum, chlorides, and sulfates. The chemical analysis revealed that the soil pH ranged within an acidic range. One sample exhibited a high TDS level. Chloride levels varied within a specific range. The concentration of organic matter in the soil exhibited variability. Sulfur trioxide and gypsum concentrations were found to be below average in the study region. The IDW technique effectively mapped the distribution of the different soil parameters within Kirkuk City, demonstrating a range from good to excellent accuracy. Additionally, a cross-validation method was employed to assess the correlation between the fundamental and investigated chemical properties. The results showed good to excellent degrees of correlation in the different structures studied.
EN
Zeolite has been successfully synthesized from clay and rice husk ash in the form of powder by using the hydrothermal method with variations in chemical compositions of alkaline solution and the amount of rice husk ash. The clay raw material was obtained from the Sidrap area of South Sulawesi and rice husk ash is obtained from the burning pile of rice husks. Sidrap clay and rice husk ash were activated using an alkaline solution of NaOH and varied rice husk ash and the addition of AlCl3. The addition of AlCl3, an alkaline solution of NaOH and H2O was used in the amount of 25.5 grams and variations of rice husk ash were 2.5 grams and 6.5 grams. Meanwhile, without the addition of AlCl3, an alkaline solution of NaOH and H2O was used for 20.5 grams and variations of rice husk ash from 2.5 grams and 6.5 grams. Then the mixture was then put into an autoclave with a temperature of 100°C for 3 hours. The basic material used in the manufacture of zeolite is carried out by X-ray Fluorescence (XRF) characterization to determine the constituent elements of basic material, which showed the content of SiO2 was 45.80 wt% in the clay and 93.40% in the rice husk ash. The crystalline structure of the zeolite formed was characterized by X-Ray Diffraction (XRD). It was found the resulting zeolite were identified as Zeolite-Y, Hydrosodalite, and ZSM-5. The microstructure properties of the resulting zeolite were determined by using Scanning Electron Microscopy (SEM).
EN
The landslide is located in Wronki. It covers the southern side on the bank of the Warta River and occupy an area of 500 m in length. The landslide was once again activated on August 22-23, 2018, causing numerous failures. The Warta River slope in the area of mass movements is built by non-construction embankments, under which the Poznań Miocene-Pliocene of quasi-layered structure lie. There are horizontal interlayers of sandy silts in these clays. The Warta drains water from a large area, and the runoff takes place mainly on the roof of clays. The slide surface of the landslide was precisely the roof of the Poznań clays. Bearing in mind the properties of the Poznań clays, such as relaxation, block disintegration, expansiveness features, the following were considered the direct causes of the failure: heavy rainfall that occurred after a drought, loading of the slope with indiscriminate cubature buildings, construction of a linear sewage system and periodically repeated vibrations caused by the implementation of neighboring investments. In order to identify the area, test boreholes were made, samples were taken for laboratory tests, and geodetic measurements were taken. Based on the obtained results, slope stability calculations were made and a measurement network was developed for systematic monitoring of geodetic displacements of control points. It was recommended to perform drainage to drain the slope and side of the Warta River, plant bushes, and make changes to the land development plan in order to prohibit further development of the area in the endangered zone.
PL
Opisywane osuwisko znajduje się w miejscowości Wronki, powiecie szamotulskim, województwie wielkopolskim. Obejmuje ono zbocze południowe, po lewej stronie rzeki Warty i zajmuje teren o rozciągłości ok. 500 m. Osuwisko po raz kolejny uaktywniło się w dniach 22-23 sierpnia 2018 r. powodując liczne awarie i zniszczenia. Skarpę Warty w obszarze występujących ruchów masowych budują nasypy niekontrolowane (o zróżnicowanym składzie), pod którymi zalegają mioceńsko-plioceńskie iły serii poznańskiej o quasi-warstwowej budowie - w iłach występują horyzontalne wkładki pyłów piaszczystych. Rzeka Warta drenuje wody z dużego obszaru, a spływ wód odbywa się głównie po stropie iłów. Strefę poślizgu stanowił właśnie strop iłów serii poznańskiej. Mając na uwadze właściwości iłów serii poznańskiej takie jak odprężenie (powstanie powierzchni zlustrzeń), dezintegracja blokowa, cechy ekspansywności (pęcznienie i skurcz), za bezpośrednią przyczynę awarii uznano: obfite opady, które wystąpiły po długotrwałej suszy, wieloletnie dociążanie skarpy nieprzemyślaną zabudową kubaturową, budowę liniowej instalacji kanalizacyjnej w obrębie skarpy oraz okresowo powtarzające się drgania spowodowane realizacją sąsiednich inwestycji (m.in. wbijanie pali czy mikrowybuchy). W celu rozpoznania terenu wykonano liczne otwory badawcze, pobrano próbki do badań laboratoryjnych, wykonano pomiary geodezyjne. Na podstawie uzyskanych wyników, dokonano obliczeń stateczności skarpy i opracowano sieć pomiarową do systematycznego monitoringu przemieszczeń geodezyjnych punków kontrolnych. Zalecono wykonanie drenażu w celu odwodnienia skarpy i zbocza Warty, posadzenie krzewów, dokonanie zmian w planie zagospodarowania przestrzennego w celu wprowadzenia zakazu dalszej zabudowy terenu w strefie zagrożonej.
EN
The moldavites are Miocene tektites foundin Central Europe. Their presence in the Badenian sediments are rare due to fluvial reworking in the area. In the clay sediments of the Poznań Formation, in the Dębina profile, one moldavite was found, which is the fourth tektite from these sediments from Poland. It had dimensions of 14 X 10 X 8 mm and a weight of 1.03 gram. The glass surface was richly ornamented, and indicates a quick deposition, without any long-distance fluvial abrasion. Currently, depending on the age ofthe sediments in which they occur, two substrewn fields of Ries-same-age and redeposited moldavites were characterized in SW Poland.
EN
The ability to effectively use mineral resources is the key to the sustainable development of industry in modern conditions of environmental protection. High-quality bentonites are rarely found in nature, so technologies for improving the quality of clay powders are quite relevant today. The article considers the possibility of improving the quality of clays obtained from candidate quarries for the purpose of further use as components of drilling fluids. The filtration and rheological characteristics of drilling fluids obtained on the basis of activated clay powder were also investigated by Benta Limited Liability Company.
17
Content available remote Zastosowanie keramzytu w remontowanych stropach i podłogach na gruncie
PL
W artykule przedstawiono właściwości i możliwe zastosowania keramzytu. Na przykładzie izolacji stropów opisano sposób aplikacji keramzytu.
EN
The article presents the properties and possible applications of expanded clay. The method of applying expanded clay is described on the example of ceiling insulation.
EN
The pattern of pore water pressure dissipation from the one-dimensional consolidation test significantly affects the calculated value of the coefficient of consolidation. This paper discusses the interpretation methodology for laboratory dissipation data from the oedometer test with the pore water pressure measurements or Rowe cell test. In the analysis, the gradient-based algorithm for finding the optimal value of the coefficient of consolidation is used against experimental results, obtained for various fine-grained soils. The appropriate value of coefficient of consolidation is considered as one with the lowest associated error function, which evaluates fitness between the experimental and theoretical dissipation curves. Based on the experimental results, two different patterns of the pore water pressure dissipation are identified, and the saturation of the specimen was found to be the key factor in describing the change in the patterns. For the monotonically decreasing dissipation curve, an inflection point is identified. The values of degree of dissipation at the inflection point are close to the theoretical value of 53.4%.
PL
W artykule omówiono wzorce rozpraszania ciśnienia wody w porach uzyskane w laboratoryjnym badaniu jednoosiowej konsolidacji. Wzorzec rozpraszania ciśnienia wody w porach istotnie wpływa na obliczoną wartość współczynnika konsolidacji. Zasadniczo istnieją dwa typy krzywych rozpraszania ciśnienia wody w porach w przestrzeni półlogarytmicznej. Typ I charakteryzuje się dylatacyjną odpowiedzią rozpraszania na etapie wzrostu ciśnienia. Czas narastania ciśnienia może być znaczny, a obliczona wartość cv z etapu rozpraszania może nie być wartością rzeczywistą. Krzywa typu II wykazuje monotonicznie zmniejszającą się odpowiedź rozpraszania i charakteryzuje się dobrze zdefiniowanym odwróconym kształtem „S” z obecnością punktu przegięcia. Dla monotonicznie malejącej krzywej dyssypacji wartości stopnia dyssypacji w punkcie przegięcia są zbliżone do wartości teoretycznej Uub = 53.4%. W pracy omówiono metodologię interpretacji laboratoryjnych danych rozpraszania ciśnienia pochodzących z badania komorze Rowe'a. W analizie wykorzystano gradientowy algorytm wyznaczania optymalnej wartości współczynnika konsolidacji w celu porównania rozwiązania teoretycznego z wynikami eksperymentalnymi, uzyskanymi dla różnych gruntów drobnoziarnistych. Optymalną wartość współczynnika konsolidacji powiązano z najniższą wartością funkcji błędu, która ocenia dopasowanie między eksperymentalną i teoretyczną krzywą rozpraszania.
PL
Temat eksperymentu przeprowadzonego z udziałem studentów Wydziału Architektury w ramach zajęć z przedmiotu rzeźba dotyczy autorskiego ćwiczenia dostosowania zmultiplikowanego naściennego modułu ceramicznego do funkcji użytkowo-wystawienniczej. Projekt opiera się na synergii multiplikowanych ceramicznych kształtek z kartką papieru i kształtowaniu obu elementów przestrzennie. Z założenia projekt ma pełnić określoną funkcję użytkowo-wystawienniczą, dedykowaną instytucjom publicznym, takim jak szkoły i przedszkola. Rozrzeźbione zmultiplikowane moduły tworzą spójny pod względem plastycznym system, a wyeksponowane w modularnej aranżacji kartki stanowią dopełnienie kompozycji. Myślą przewodnią eksperymentu było kreowanie formy plastycznej wraz z kształtowaniem własności użytkowych. Rozwiązanie to miałoby na celu również wizualne uatrakcyjnienie przestrzeni publicznej.
EN
The subject of the experiment, carried out with the participation of Architecture Faculty students in Poznan as part of their sculpting course, concerns an authorial exercise of adjusting a multiplied ceramic wall-module to its utility and exhibitive function. The project is based on the synergy of multiplied ceramic shapes with sheets of paper and shaping both components spatially. By definition, the project is supposed to fulfil a specific exhibitive function intended for public institutions, like schools and kindergartens. The sculpted modules make up a system that is coherent in terms of plasticity, while the pieces of paper displayed in a modular arrangement complete the composition. The main idea of the experiment was to create an artistic form along with shaping its practical properties. This solution is also intended to make public spaces more appealing visually.
20
Content available Czy zamienimy beton na glinę?
PL
Jednym z mało docenianych współcześnie materiałów proekologicznych mogącym służyć do wyrobu szerokiej gamy wyrobów budowlanych jest glina suszona. Podczas realizacji współczesnych inwestycji wydobywana z gruntu glina na budowie jest traktowana najczęściej jako odpad, który należy usunąć. Pozyskiwany w ten sposób materiał mógłby współcześnie podlegać wstępnej ocenie składu i przydatności dla wykonania różnych wyrobów od materiałów ściennych konstrukcyjnych, przez wyroby spełniające rolę izolacyjną, po wyroby stanowiące warstwę wykończeniową.
EN
One of the currently little appreciated pro-ecological materials that can be used to manufacture a wide range of construction products is dried clay. During the implementation of modern investments, the clay extracted from the ground at the construction site is most often treated as waste that needs to be removed. The material obtained for this material could now be subject to a preliminary assessment of its composition and suitability for the production of various products, from structural wall materials, through products fulfilling an insulating role, to products constituting the finishing layer.
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