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  1. 8 Cement Lime Concrete
  2. 8 Cement Wapno Beton
  3. 7 Materiały Budowlane
  4. 4 Archives of Civil and Mechanical Engineering
  5. 2 Materials Science Poland
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  1. 3 Seshu D. R.
  2. 2 Adamczewski Grzegorz
  3. 2 Błaszczyński T. Z.
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  5. 2 Pawluczuk Edyta
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1
Content available remote Aktywowany alkalicznie popiół lotny jako zamiennik cementu w mieszankach betonowych
Zieliński Krzysztof, Herbowska Martyna, Krawczyk Jacek
Materiały Budowlane
|
2024
|
nr 5
5--8
PL
W artykule zaprezentowano wyniki badań betonu wykonanego przy użyciu spoiwa mineralnego geopolimerowego. Betony wykonane zostały na bazie aktywowanego alkalicznie popiołu lotnego krzemionkowego bez dodatku cementu. Wykonano trzy rodzaje betonu geopolimerowego. Rolę aktywatora w sporządzonych mieszankach pełniła mieszanina zasady sodowej oraz szkła wodnego. Przygotowano trzy roztwory zasady sodowej o narastającym stężeniu molowym: 6M, 9M oraz 12M. Przygotowany roztwór mieszano ze szkłem wodnym w proporcji wagowej 1:1. Dla każdego stężenia wykonano pomiary w temperaturze dojrzewania 20°C i po utwardzaniu przez 24 h w 60°C. Wykonano badania wytrzymałości na ściskanie oraz na zginanie po 28 dniach dojrzewania oraz badanie nasiąkliwości i mrozoodporności. Analiza uzyskanych wyników badań wykazała, źe beton geopolimerowy może znaleźć zastosowanie w budownictwie, jako alternatywne rozwiązanie dla standardowych cementów powszechnego użytku, generując znacznie mniejszy ślad węglowy niż standardowe cementy.
EN
The article presents the results of tests on concrete made using a geopolymer mineral binder. The concretes were made on the basis of alkaline-activated silica fly ash without the addition of cement. Three types of geopolymer concrete were made. The role of the activator in the prepared mixtures was played by a mixture of sodium base and water glass. Three solutions of sodium alkali with increasing molar concentration were prepared: 6M, 9M and 12M. The prepared solution was mixed in a 1:1 weight ratio with water glass. For each concentration, measurements were made at a ripening temperature of 20°C and after hardening for 24 hours at 60°C. Compressive and bending strength tests were performed after 28 days of maturing, as well as water absorption and frost resistance tests. The analysis of the obtained test results showed that geopolymer concrete can be used in construction as an alternative solution to standard common cements, generating a much smaller carbon footprint than standard cements.
2
Content available Modyfikacja właściwości kompozytów geopolimerowych z kruszywem z recyklingu betonu z przeznaczeniem na ustrój nośny mostu
Duch Krzysztof, Pawluczuk Edyta
Przegląd Budowlany
|
2023
|
R. 94, nr 11-12
186--191
PL
Artykuł jest streszczeniem pracy magisterskiej dotyczącej badania i zastosowania w budownictwie betonów geopolimerowych z dodatkiem kruszywa z recyklingu. Zaprezentowano badania optymalizacyjne z dwoma zmiennymi: zawartość kruszywa z recyklingu i granulowanego mielonego żużla wielkopiecowego. Wybrany na podstawie badań materiał o najwyższej wytrzymałości i najlepszych parametrach przyjęto do zaprojektowania elementu mostu.
EN
The article is a summary of the master’s thesis on the study and application of geopolymer concretes with the addition of recycled aggregate in construction. Optimization studies with two variables were presented: the content of recycled aggregate and granulated ground blast furnace slag. The material with the highest strength and the best parameters selected on the basis of tests was adopted to design the bridge element.
3
Content available remote Hydration, Microstructure, and Properties of Fly Ash-Based Geopolymer: A Review
Khawaji Mohammad
Materials Science Poland
|
2023
|
Vol. 41, No. 2
263--287
EN
Geopolymers have gained attention as a potential eco-friendly alternative to Portland cement, primarily due to their reduced carbon dioxide emissions and the opportunity to repurpose industrial waste materials. Fly ash (FA), a byproduct of coal combustion, has been favored as a raw material for geopolymer concrete owing to its widespread availability and high concentrations of alumina and silica. The development and application of fly ash-based geopolymer concrete can contribute significantly to production of sustainable construction materials. An in-depth analysis of fly ash-based geopolymer concrete has been conducted to explore its potential as a substitute for traditional concrete. This review encompasses the underlying reaction mechanism, strength, long-term durability, and microstructural characteristics of geopolymer concrete. The present review paper shows that adding the optimal quantity of fly ash improves the performance of fly ash-based geopolymer when exposed to extreme durability conditions, as well as improving strength properties. The microstructural analysis shows that when fly ash is added, the microstructure of the concrete matrix would be dense and packed. However, challenges remain in adopting fly ash-based geopolymer concrete for large-scale construction projects, as the existing literature presents inconsistencies in the reported strength, durability, and test results. Further research is necessary to consolidate knowledge on the behavior and mechanism of fly ash-based geopolymer concrete and to ultimately provide comprehensive data to support its widespread implementation in the construction industry.
4
Content available Research on cement-free composites based on alkaline-activated waste materials
Nalewajko Marta
Economics and Environment
|
2023
|
No. 3
453--467
EN
The article presents a review of research conducted on cement-free concretes based on alkaline-activated waste materials. Research is conducted in order to create concretes that are in line with the doctrine of sustainable development. Their main assumption is the reuse of recycled materials in newly produced building materials without compromising their properties. In addition, attempts are made to eliminate Portland cement, replacing it partially or completely with fly ashes or metakaolin. Another modification of concrete consists of replacing natural aggregate with artificial aggregate. The research conducted on lightweight concretes based on fly ashes, and alkali-activated porous ash aggregate is also presented.
PL
Artykuł przedstawia wyniki badań prowadzonych na betonach bezcementowych na bazie surowców odpadowych aktywowanych alkalicznie. Prace badawcze mają na celu stworzenie betonów wpisujących się w doktrynę zasad zrównoważonego rozwoju, którego głównym założeniem jest ponowne wykorzystywanie materiałów z recyklingu w nowo produkowanych materiałach budowlanych przy zachowaniu ich właściwości. Ponadto, dąży się do eliminacji cementu portlandzkiego poprzez zastąpienie go częściowo bądź całościowo popiołami lotnymi czy metakaolinem. Modyfikacja betonu zakłada również zastąpienie kruszywa naturalnego kruszywem sztucznym. Niniejszy artykuł prezentuje wyniki badań prowadzonych na betonach lekkich na bazie popiołów lotnych i kruszywa popiołoporytowego aktywowanych alkalicznie.
5
Content available remote Evaluating the impact of nano‑silica on characteristics of self‑compacting geopolymer concrete with waste tire steel fiber
Althoey Fadi, Zaid Osama, Alsharari Fahad, Yosri Ahmed. M., Isleem Haytham F.
Archives of Civil and Mechanical Engineering
|
2023
|
Vol. 23, no. 1
art. no. e48, 2023
EN
The demand for cement-free concrete is increasing worldwide to make the construction industry closer to being sustainable. The current research’s main objective was to develop self-compacting fiber-reinforced geopolymer concrete using waste/recycled materials. Steel wire from an old discarded tire was cut to make steel fibers. Wheat straw ash, an agricultural waste material, was utilized as the primary binder, and alkali-activated solutions were used as the precursors. Further, nano-silica (NS) was added from 0.5 to 3.0%, and waste tire steel fibers (WTSF) were added from 1 to 3.5% by binder content in different mixes. To evaluate the characteristics of different concrete, tests were performed, such as compressive, split tensile, and flexural strength for mechanical properties and sorptivity, rapid chloride penetration (RCP), and drying shrinkage tests for durability properties. It was noted that at 2.5% NS and 3.0% WTSF, the strength increases as 71.5, 6.5, and 8.2 MPa strength was achieved at 90 days for compressive, split tensile and flexural strength. For the RCP test, all samples were categorized as “low” in electrical conductance, micro-strains for drying shrinkage all came in an acceptable range for all samples, and sorptivity values were higher in earlier curing phases than in later phases of concrete. To understand the phase analysis of concrete, x-ray diffraction (XRD) analysis was performed, and it was revealed that the M5 mix (2.5% NS + 3.0% WTSF) had the highest peaks of C-S-H, N-A-S-H, and C-A-S-H, which demonstrates the densified microstructure of concrete with addition of nano-silica.
6
Content available remote Effectiveness of nano-SiO2 on the mechanical, durability, and microstructural behavior of geopolymer concrete at different curing ages
Ahmed Hemn Unis, Mohammed Azad A., Mohammed Ahmed Salih
Archives of Civil and Mechanical Engineering
|
2023
|
Vol. 23, no. 2
art. no. e129, 2023
EN
The invention and development of new binding construction materials to replace conventional Portland cement are now essential from the perspective of environmental concerns. Geopolymers are a potential solution to this problem. Geopolymers are innovative cementitious materials with the potential to replace Portland cement in manufacturing concrete composites. Nanomaterials offer novel features and performances to geopolymer composites by enhancing the composite's microstructural characteristics by forming extra calcium-silicate-hydrate (C-S-H), sodium-alumino-silicate-hydrate (N-A-S-H), and calcium-alumino-silicate-hydrate (C-A-S-H) gels, as well as the filling nano-pores in the matrix. In this study, extensive experimental laboratory works have been conducted on around 250 geopolymer concrete (GPC) specimens to investigate the effects of adding different dosages (1, 2, 3, and 4%) of nano-silica (NS) on the fresh, compressive strength, splitting tensile strength, flexural strength, stress-strain behaviors, modulus of elasticity, water absorption, rapid chloride permeability, resistance to an acidic environment, and microstructural properties like scanning electron microscopy (SEM) and X-ray diffraction (XRD) of geopolymer concrete composites. As a result of the addition of NS, it was found that the largest improvement in compressive strength was occurred at 3% NS, which was 6.3, 13.4, 20.5, 21, and 21.9% at 3, 7, 28, 90, and 180 days, respectively, compared to the control GPC mixture. Also, the maximum improvement in water absorption was nearly similar for 2 and 3% of NS content, which was 32.2 and 38% at 28 and 90 days, respectively, compared to the control GPC mixture. Furthermore, according to SEM observations, the addition of NS improved the microstructural characteristics of the GPC specimens due to the formation of additional geopolymerization products, as revealed by XRD analyses. However, the fresh characteristics of the geopolymer concrete mixtures are reduced due to the addition of NS to the GPC mixtures.
7
Content available remote Propozycja wykorzystania betonów geopolimerowych do prefabrykatów o podwyższonej izolacyjności cieplnej
Nietupski Adam, Bołtryk Michał, Pawluczuk Edyta, Kalinowska-Wichrowska Katarzyna, Spodzieja Szymon
Materiały Budowlane
|
2022
|
nr 4
34--37
PL
W artykule zaproponowano zastosowanie geopolimerów na bazie kruszywa sztucznego do produkcji elementów prefabrykowanych o podwyższonej izolacyjności. Przeprowadzono eksperyment o zmiennej zawartości popiołu lotnego (PL) i mieszaniny popiołowo-żużlowej (MPŻ) oraz różnym stężeniu aktywatora NaOH. Zastosowana metoda zagęszczania w postaci wibroprasowania umożliwia wytworzenie drobnowymiarowych elementów ściennych i stropowych o dobrych właściwościach izolacyjnych przy wytrzymałości na ściskanie ok. 15 MPa.
EN
The article proposes the use of geopolymers on artificial aggregate for prefabricated elements with increased insulation. An experiment was carried out with a variable content of fly ash (PL) and a mixture of ash and slag (MPŻ) and a different concentration of NaOH activator. The applied method of compaction in the form of vibropress allows the production of small-sized wall and ceiling elements with good insulating properties and a compressive strength of about 15 MPa.
8
Content available remote Podstawowe właściwości geopolimerów z dodatkiem odpadu ceramicznego
Chuczun Aleksandra, Rakowski Bartosz, Gosk Edyta, Kalinowska-Wichrowska Katarzyna
Materiały Budowlane
|
2022
|
nr 8
80--83
PL
W artykule przedstawiono podstawowe właściwości geopolimerów z dodatkiem miału ceramicznego, tj.: wytrzymałość na zginanie i ściskanie, nasiąkliwość wagową, gęstość objętościową. Wykonano analizę SEM kompozytów i badania chemiczne surowców. Przyjęto stałą zawartość dodatku odpadowego, zmienną temperaturę wygrzewania i zawartość aktywatora. Wyniki wskazują na korzystny wpływ dodatku miału ceramicznego na badane cechy kompozytów.
EN
The article presents the basic properties of geopolymers with the use of ceramic fines, i.e. flexural and compressive strength, water absorption, bulk density. SEM analysis of composites and chemical tests of research raw materials were performed. A constant content of waste additive, a variable curing temperature and activator content were assumed. The results show a beneficial effect of the addition of ceramic fines on the examined properties of the composites.
9
Content available remote Earth Friendly Concrete : „zielona alternatywa” dla typowych mieszanek betonowych
Owsiak Daniel
Geoinżynieria : drogi, mosty, tunele
|
2022
|
nr 3
88--90
10
Content available Finite Element Analysis on Structural Behaviour of Geopolymer Reinforced Concrete Beam using Johnson-Cook Damage in ABAQUS
Mortar Nurul Aida Mohd, Al Bakri Abdullah Mohd Mustafa, Hussin Kamarudin, Razak Rafiza Abdul, Hamat Sanusi, Hilmi Ahmad Humaizi, Shahedan Noorfifi Natasha, Li Long Yuan, Aziz Ikmal Hakem A.
Archives of Metallurgy and Materials
|
2022
|
Vol. 67, iss. 4
1349--1354
EN
This paper details a finite element analysis of the behaviour of Si-Al geopolymer concrete beam reinforced steel bar under an impulsive load and hyper velocity speed up to 1 km/s created by an air blast explosion. The initial torsion stiffness and ultimate torsion strength of the beam increased with increasing compressive strength and decreasing stirrup ratio. The study involves building a finite element model to detail the stress distribution and compute the level of damage, displacement, and cracks development on the geopolymer concrete reinforcement beam. This was done in ABAQUS, where a computational model of the finite element was used to determine the elasticity, plasticity, concrete tension damages, concrete damage plasticity, and the viability of the Johnson-Cook Damage method on the Si-Al geopolymer concrete. The results from the numerical simulation show that an increase in the load magnitude at the midspan of the beam leads to a percentage increase in the ultimate damage of the reinforced geopolymer beams failing in shear plastic deformation. The correlation between the numerical and experimental blasting results confirmed that the damage pattern accurately predicts the response of the steel reinforcement Si-Al geopolymer concrete beams, concluded that decreasing the scaled distance from 0.298 kg/m3 to 0.149 kg/m3 increased the deformation percentage.
11
Content available remote To determine the performance of metakaolin‑based fiber‑reinforced geopolymer concrete with recycled aggregates
Zaid Osama, Martínez-García Rebeca, Abadel Aref A., Fraile-Fernández Fernando J., Alshaikh Ibrahim M. H., Palencia-Coto Covadonga
Archives of Civil and Mechanical Engineering
|
2022
|
Vol. 22, no. 3
art. no. e114
EN
In the present research, geopolymer concrete for construction applications comprising metakaolin was evaluated by partial addition of recycled coarse aggregates and steel fibers to develop eco-friendly cementitious composites. Mechanical and durability characteristics of geopolymer composites were then assessed such as compression, splitting tensile and flexural strength, water absorption, and drying shrinkage. It was observed that with the inclusion of steel fibers, no significant change in compressive strength occurred. Mixtures were prepared with a binder amount of 440 kg/m3 in total. The recycled coarse aggregates were substituted with natural coarse aggregates at a rate of 15, 25, and 35% by their weight. The inclusion of steel fibers in the mixes was 1.0, 2.0, and 3.0% of metakaolin content. Because of the addition of steel fibers, the split tensile strength, flexural strength, and drying shrinkage were improved significantly. The load-displacement graph showed that the fracture toughness of geopolymer composites was enhanced due to the inclusion of steel fibers which leads to maximum loads capacity. From the stress-strain curve, it was observed that the geopolymer paste and the steel fibers had a strong bond, which will help in restraining the propagation of cracks. From XRD analysis, it was shown that a mix having 25% recycled coarse aggregates and 3.0% steel fibers in metakaolin-based geopolymer concrete results in environment-friendly composite with suitable strength and durability that will help in bringing sustainability to the construction industry.
12
Content available remote Development of metakaolin‑based geopolymer rubberized concrete: fresh and hardened properties
Alsaif Abdulaziz, Albidah Abdulrahman, Abadel Aref, Abbas Husain, Al-Salloum Yousef
Archives of Civil and Mechanical Engineering
|
2022
|
Vol. 22, no. 3
art. no. e144
EN
During the past two decades, geopolymer concrete has been investigated as a sustainable alternative to Portland cement concrete, which is known to generate a huge amount of CO2 in the environment. This study focuses on the assessment of the fresh and hardened mechanical properties and durability of metakaolin (MK)-based geopolymer rubberized concrete. Crumb rubber was derived from discarded waste tires, another pollution source to the environment, and incorporated in concrete as fine aggregate replacement in ratios from 10 to 50% by volume. The performance of the MK-based geopolymer rubberized concrete is discussed based on its workability, air content, stress-strain behavior (including compressive strength and modulus of elasticity), flexural strength, dry unit weight and rapid chloride penetrability. The results show that the proposed sustainable concrete mixes achieve acceptable fresh and hardened mechanical and durability properties. The compressive strength when crumb rubber replaces fine aggregates in volumetric percentages between 10 and 40% are in the range of 28.7-39.7 MPa. Furthermore, the unit weight and modulus of elasticity of the MK-based geopolymer rubberized concrete mix with 40% rubber replacement are 14.9 GPa and 2134 kg/m3, respectively. This can promote a potentially large market for the MK-based geopolymer rubberized concrete products in applications where the priority is for decreasing self-weight and increasing flexibility rather than strength.
13
Content available Use of waste paper ash or wood ash as substitution to fly ash in production of geopolymer concrete
Owaid Haider M., Al-Rubaye Muna M., Al-Baghdadi Haider M.
Przegląd Naukowy Inżynieria i Kształtowanie Środowiska
|
2021
|
Vol. 30, No. 3
464--476
EN
Large quantities of paper and wood waste are generated every day, the disposal of these waste products is a problem because it requires huge space for their disposal. The possibility of using these wastes can mitigate the environmental problems related to them. This study presents an investigation on the feasibility of inclusion of waste paper ash (WPA) or wood ash (WA) as replacement materials for fly ash (FA) class F in preparation geopolymer concrete (GC). The developed geopolymer concretes for this study were prepared at replacement ratios of FA by WPA or WA of 25, 50, 75 and 100% in addition to a control mix containing 100% of FA. Sodium hydroxide (NaOH) solutions and sodium silicate (Na2SiO3) are used as alkaline activators with 1M and 10M of sodium hydroxide solution.The geopolymer concretes have been evaluated with respect to the workability, the compressive strength, splitting tensile strength and flexural strength. The results indicated that there were no significant differences in the workability of the control GC mix and the developed GC mixes incorporating WPA or WA. Also, the results showed that, by incorporating of 25–50% PWA or 25% WA, the mechanical properties (compressive strength, splitting tensile strength and flexural strength) of GC mixes slightly decreased. While replacement with 75–100% WPA or with 50–100% WA has reduced these mechanical properties of GC mixes. As a result, there is a feasibility of partial replacement of FA by up to 50% WPA or 25% WA in preparation of the geopolymer concrete.
14
Content available remote Aspekty materiałowo-technologiczne w strategii realizacji budownictwa prefabrykowanego XXI wieku
Woyciechowski Piotr, Adamczewski Grzegorz
Materiały Budowlane
|
2021
|
nr 11
12--16
15
Content available remote Effect of sea sand and recycled aggregate replacement on fly ash/slag-based geopolymer concrete
Li Weiwen, Huang Xinlin, Zhao Jiali, Huang Yujie, Shumuye Eskinder Desta, Yang Xu
Materials Science Poland
|
2021
|
Vol. 39, No. 4
580--598
EN
The purpose of this study is to investigate the impact of recycled aggregate (RA) and sea sand (SS) replacement on fly ash (FA) slag-based geopolymer concrete (GPC). An orthogonal array design is employed to obtain the optimum mix proportions, and geopolymer mixes are prepared using slag percentages of 10%, 20%, and 30% slag in FA/slag-based GPC. Sodium hydroxide (NaOH) solution is prepared at three concentrations (8 mol/L, 12 mol/L, and 16 mol/L). The mechanical properties of the geopolymer mixes are determined based on the tensile strength, compressive strength, flexural strength, and elastic modulus. GPC is prepared using water-binder ratios of 0.3, 0.4, and 0.5 at 0%, 25%, 50%, 75%, and 100% of RA replacement. The results showed that the variation in the RA replacement ratio had little effect on the strength and elastic modulus of sea sand geopolymer concrete (SS–GPC), but it had a significant effect on river sand geopolymer concrete (RS–GPC). The RA replacement ratio also showed a noticeable change in the damage surface of the specimens. In addition, SS hinders the hydration reaction of the geopolymer in the early stage and reduces the early strength of the GPC; however, in the later stages, the effect becomes insignificant.
16
Content available remote Porównawcze badania wytrzymałości na odrywanie od powierzchni międzyfazowej jednorodnego betonu geopolimerowego
Kumar Sumanth B., Seshu Rama D.
Cement Wapno Beton
|
2021
|
R. 26, nr 1
3--11
PL
Beton geopolimerowy jest kompozytem, który ma potencjalne możliwości aby zostać alternatywnym materiałem dla tradycyjnego betonu. W pracy przedstawiono doświadczenia związane z odrywaniem od powierzchni międzyfazowej jednorodnego betonu geopolimerowego. Sporządzono do doświadczeń 18 próbek do odrywania powierzchni zbrojonych i niezbrojonych, przechodzących przez powierzchnię międzyfazową. Oznaczoną doświadczalnie wytrzymałość na odrywanie betonu geopolimerowgo porównano z wytrzymałością na odrywanie stosując dostępne modele analityczne dla betonu zwykłego. Wyniki doświadczeń wykazały, że wytrzymałość na odrywanie od powierzchni międzyfazowej jednorodnego betonu geopolimerowego, wzrastała do pewnej wytrzymałości na ściskanie tego betonu. Większość dostępnych modeli analitycznych stosują znane metody w ocenie wytrzymałości na odrywanie betonu geopolimerowego.
EN
Geopolymer concrete is the composite and has prospective potential to become one of the alternatives to conventional concrete. This paper presents an experimental investigation on the shear strength of monolithic geopolymer concrete interface. A total of 18 push-off specimens with and without reinforcement across the interface were cast and tested. The experimental shear strength of geopolymer concrete is compared with the shear strength evaluated, using the available analytical models for normal concrete. The test results indicated that the shear strength of monolithic geopolymer concrete interface has increased up to certain compression strength of geopolymer concrete. Most of the available analytical models are conservative in estimating the shear strength of geopolymer concrete.
17
Content available remote Mikrostruktura i właściwości geopolimerów powstających w procesie alkalicznej aktywacji popiołu lotnego
Rajczyk Krystyna, Janus Grzegorz
Cement Wapno Beton
|
2021
|
R. 26, nr 4
279--293
PL
W pracy przedstawiono wyniki badań możliwości otrzymania trwałego betonu geopolimerowego o dużej wytrzymałości, którego podstawowym składnikiem jest popiół lotny. W wyniku przeprowadzonych badań ustalono, że największą możliwość uzyskania betonu geopolimerowego o dużej wytrzymałości wykazały drobnoziarniste, specjalnie wyselekcjonowane popioły krzemionkowe ze spalania węgla kamiennego, nazywane ultra drobnymi popiołami. Jednak beton geopolimerowy, otrzymany przez alkaliczną aktywację tych popiołów 8M roztworem NaOH, nie jest odporny na cykliczne zamrażanie i rozmrażanie. Zastąpienie 15% popiołu lotnego prażoną odpadową gliną oraz stosowanie aktywatora, stanowiącego mieszaninę roztworu NaOH i szkła wodnego, znacznie zwiększyły trwałość tego betonu. Ta modyfikacja składu betonu wpłynęła na zmianę mikrostruktury matrycy w betonie, w której między innymi stwierdzono w badaniach, występowanie krystalicznego kankrynitu.
EN
The paper presents the results of the study on the possibility of obtaining high-strength durable geopolymer concrete with fly ash as the basic component. As a result of the research conducted, it was found that the highest potential to obtain geopolymer concrete with high strength was shown for fine-grained, specially selected siliceous ashes from coal combustion. However, the geopolymer concrete obtained by alkaline activation of these ashes with the 8M NaOH solution was not resistant to freeze-thaw cycles. Replacement of 15% fly ash with calcined waste clay and the use of the mixture of NaOH solution and water glass as an activator substantially increased the durability of this concrete. This modification of the concrete composition changed the microstructure of the matrix in the hardened concrete, since the cancrinite was found in the study.
18
Content available remote Badanie betonu geopolimerowego z kruszywem z żużla żelazochromowego na działanie podwyższonej temperatury
Indu P., Greeshma S.
Cement Wapno Beton
|
2021
|
R. 26, nr 4
340--351
PL
Niniejszy artykuł dotyczy wytrzymałości i ubytku masy betonu geopolimerowego w porównaniu z konwencjonalnym betonem cementowym, po ekspozycji w podwyższonej temperaturze. W niniejszej pracy kruszywo grube konwencjonalnego betonu geopolimerowego zostało częściowo (40%) zastąpione kruszywem z żużla żelazochromowego w celu uzyskania mieszanki zastępczej betonu geopolimerowego. Omówiono również mikrostrukturę betonu geopolimerowego na podstawie badań XRD, SEM i tomografi i rentgenowskiej. W wyniku badań stwierdzono, że po ekspozycji w podwyższonej temperaturze, konwencjonalny beton cementowy wykazuje spadek wytrzymałości większy o 17,65% od konwencjonalnego betonu geopolimerowego. Zauważono również, że zastępcza mieszanka geopolimerowa wykazuje utratę wytrzymałości o 24,4% większą i utratę masy o 1,35% większą niż konwencjonalna mieszanka geopolimerowa. Jednak w większości zakresów temperatur miała ona większą wytrzymałość od konwencjonalnej mieszanki geopolimerowej. Tak więc mieszanka zastępcza betonu geopolimerowego zachowuje się lepiej niż konwencjonalny beton geopolimerowy i konwencjonalny beton cementowy zarówno w warunkach otoczenia, jak i w podwyższonej temperaturze.
EN
This paper deals with the strength and mass loss of geopolymer concrete in comparison with conventional cement concrete after elevated temperature exposure. In this study, the coarse aggregates of the conventional geopolymer concrete are replaced partially (40%) with ferrochrome slag aggregates, to obtain the replacement mix of geopolymer concrete. The microstructure of geopolymer concrete was examined by XRD, X-ray tomography, and SEM and also discussed in this paper. The results concluded that after exposure at elevated temperature, the conventional cement concrete has a strength loss of about 18% higher than the geopolymer concrete. It was also noted that though replacement geopolymer mix exhibited the strength loss of 24.4% and mass loss of 1.35% higher than the conventional geopolymer mix, it had greater strength than conventional geopolymer mix, for most of the temperature ranges. Thus the replacement mix of geopolymer concrete behaves better than conventional geopolymer concrete, both at ambient and elevated temperature conditions.
19
Content available Microstructural, mechanical and pozzolanic characteristics of metakaolin-based geopolymer
Abiodun Yetunde Oyebolaji, Sadiq Obanishola Muftau, Odeosun Samson Oluropo
Geology, Geophysics and Environment
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2020
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Vol. 46, no. 1
57--69
EN
The use of cement contributes to global CO2 emission and this leads to the depletion of ozone layer, causing global warming. The quest to reduce or eliminate this problem has resulted in the discovery of metakaolin-based geopolymer as an alternative to the use of cement in construction work. In this study, metakaolin obtained as a result of kaolin calcination from some deposits in Nigeria; Ogun (Imeko), Edo (Okpela), Ondo (Ifon) and Ekiti (Isan-Ekiti) were characterized and used to determine the compressive and flexural strength of metakaolin-based geopolymer concrete (Mk-GPC). Cubes of 150 × 150 × 150 mm were used for the compressive strength test and reinforced concrete beams of size 150 × 250 × 2160 mm were produced to test for flexural strength. A water-absorption test was also carried out on Mk-GPC and the effect of ball-milling was assessed on the strength properties. The results from the various tests showed that 800°C for 1 hour of calcination of kaolin gives best combination of performance properties due to the presence of amorphous silica in metakaolin. Mk-GPC gave higher compressive strength and at an early age than ordinary Portland cement (OPC) concrete. The water absorption capacities of Mk-GPC were higher than the control samples. In the flexural strength test, the reinforced beams failed in flexural-shear mode and the shear capacities at 28-, 56- and 90-day curing age of the beams were between 0.656 and 0.938 MPa for Mk-GPC beams and between 0.563 and 0.844 MPa for the control beams. The moment capacities for the beams were between 19.25 and 33.25 (×10³ kgm²/s²) for Mk-GPC beams and were between 22.75 and 28.0 (×10³ kgm²/s²) for the control beams. The study has revealed that metakaolin-based geopolymer can serve as an alternative to cement for sustainable construction in the Nigerian construction industry.
20
Content available remote Kierunki rozwoju prefabrykacji
Adamczewski Grzegorz, Woyciechowski Piotr
Materiały Budowlane
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2019
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nr 10
57--59
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