scholarly journals Sulfate-bearing clay and Pietra Serena sludge: Raw materials for the development of alkali activated binders

2021 ◽  
Vol 301 ◽  
pp. 124030
Author(s):  
Roberta Occhipinti ◽  
Ana M. Fernández-Jiménez ◽  
Angel Palomo ◽  
Serena C. Tarantino ◽  
Michele Zema
Keyword(s):  
Raw Materials ◽  
Alkali Activated Binders ◽  
Alkali Activated

Alkali Activated Binders Based on Metakaolin

2015 ◽  
Vol 1 ◽  
pp. 200
Author(s):  
Laura Sele ◽  
Diana Bajare ◽  
Girts Bumanis ◽  
Laura Dembovska
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Water Absorption ◽  
Raw Materials ◽  
Sodium Silicate Solution ◽  
Total Porosity ◽  
Lead Silicate ◽  
Cement Production ◽  
Alkali Activated Binders ◽  
Alkali Activated

<p>According to research conducted in last 25 years, alkali activated binders have been considered as one of the most progressive alternative binders, which can effectively replace Portland cement. Production of alkali activated binders differs from the Portland cement production and is associated with lower CO2 emissions. The use of recycled industrial by-products and wastes is also possible, what corresponds to the future guidelines and principles of sustainable binder production in the world.<br />The aim of this study was to create innovative alkali activated binders by using secondary raw materials, which will be different from the ones described in the scientific literature – alkali activated binders with porous structure. Raw materials used for the binders were metakaolin containing waste, waste from aluminium scrap recycling factory and recycled lead-silicate glass; solid contents were activated with modified sodium silicate solution with an addition of sodium hydroxide.<br />The physical properties of alkali activated binders, such as density, water absorption, open and total porosity, were determined and flexural and compressive strength of hardened alkali-activated binders were tested at the age of 28 days. Durability was examined by sulphate resistance test, which was performed according to SIA 262/1, appendix D: applicability and relevance for use in practice. 40x40x160 mm prismatic specimens were used for expansion measurement and determination of compressive strength. <br />The open porosity of obtained materials was up to 45%, density from 380 to 1720 kg/m3, compressive strength up to 29,8 MPa, water absorption 6 – 114 wt.%. After analysing the results from the sulphate test it was concluded that glass additive reduced the alkali activated binder resistance to sulphate attack.</p>

scholarly journals STRUCTURE FORMATION IN ALKALI ACTIVATED ALUMINOSILICATE BINDING SYSTEMS USING NATURAL RAW MATERIALS WITH DIFFERENT CRYSTALLINITY DEGREE

2020 ◽  
pp. 38-43 ◽  
Author(s):  
N. Kozhuhova ◽  
V. Strokova ◽  
M. Kozhuhova ◽  
Igor' Zhernovskiy
Keyword(s):  
Structure Formation ◽  
Raw Materials ◽  
Construction Material ◽  
Construction Materials ◽  
Deep Understanding ◽  
Science Field ◽  
Crystallinity Degree ◽  
Classic Problem ◽  
Alkali Activated Binders ◽  
Alkali Activated

the efficiency of traditional raw materials using as well as expanding of potential uses for non-conventional and alternative raw materials with different origin is the tasks exiting interest among material scientists and manufacture stuff. Investigation of the above is oriented on solution of such scientific problem as more deep understanding of structure and features of material. The results obtained also allow solution of some technological, technical and economical tasks. Greatly, it is actual when using of new types of raw materials as well as when synthesis of new composites. Concerning the construction material science field, the classic problem is the looking for ways to study the reactivity of raw components under different conditions, its control and, generally, its increasing to produce higher performance materials. Among the popular and widely-used construction materials are alkali-activated binders and relevant composites. In this study the results of granulometric analysis of suspension based on alkali-activated aluminosilicate with different crystallinity degree are presented. It was found, when treatment of aluminosilicate grain by alkali activator leads to the grain solubilizing (but differently depending on crystallinity degree of aluminosilicate) and formation of alkali-aluminosilicate gel that reacts with unreacted part of the grain according to structure affinity principle. It was also determined the crystallinity degree of aluminosilicate component is inversely proportional to its solubility in highly-alkali environment. The model of structure formation for geopolymer system under alkali effect is offered.

Preparation and Properties of Pressed Metakaolin and Fly Ash Based Alkali-Activated Binders

2014 ◽  
Vol 897 ◽  
pp. 65-68 ◽  
Author(s):  
Jana Boháčová ◽  
Stanislav Staněk ◽  
Pavel Mec
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
High Temperatures ◽  
Frost Resistance ◽  
Raw Materials ◽  
Fly Ashes ◽  
Secondary Raw Materials ◽  
Alkali Activated Binders ◽  
Alkali Activated

Metakaolin, fly ashes and other secondary raw materials serves as suitable input in preparation of alkali-activated binders. This work deals with preparation of alkali-activated materials based on metakaoline and fly ash. Mixtures were prepared with a minimum of mixture water, ready for pressing. Prepared specimens were tested for tensile strength and pressure strength, resistance to high temperatures, frost resistance and resistance to water and salt.

Review of Geopolymer Materials for Thermal Insulating Applications

2015 ◽  
Vol 660 ◽  
pp. 17-22 ◽  
Author(s):  
Emy Aizat Azimi ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Liew Yun Ming ◽  
Cheng Yong Heah ◽  
Kamarudin Hussin ◽  
...  
Keyword(s):  
Chemical Resistance ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Good Resistance ◽  
Thermal Insulating ◽  
Cementitious Binder ◽  
Alkali Activated Binders ◽  
Alkali Activated ◽  
Geopolymer Composites ◽  
Geopolymer Material

Geopolymer is an environmentally cementitious binder that does not require the existence of ordinary Portland cement (OPC). Geopolymer has many excellent advantages, including high early strength, low shrinkage, good thermal resistance and good chemical resistance. Based on previous research, geopolymer offered good resistance to corrosion, abrasion and heat. Fly ash, metakaolin, kaolin, and slag are regularly used raw materials for the preparation of geopolymer composites. Geopolymer composites also offer a potential environmental friendly product by reduce the carbon dioxide (CO2) emissions. This geopolymer material also offers an innovative and sustainable solution for maintaining infrastructure and also provides superior thermal, chemical and mechanical performance. This paper summarizes some research outcomes on alkali-activated binders along with the potential of geopolymer composites for thermal insulating applications.

scholarly journals Interfacial Transition Zone Between Aggregate And Alkali-Activated Blast Furnace Slag – A Scanning Electron Microscopy

2018 ◽  
Vol 64 (4) ◽  
pp. 23-27
Author(s):  
Pavel Mec ◽  
Lucie Gembalová
Keyword(s):  
Electron Microscopy ◽  
Blast Furnace Slag ◽  
Raw Materials ◽  
Interfacial Transition Zone ◽  
Cement Concrete ◽  
Metallurgical Production ◽  
Bonding Phase ◽  
Alkali Activated Binders ◽  
Furnace Slag ◽  
Alkali Activated

Abstract Alkali-activated binders are currently a widely-researched material. Thanks to the use of secondary raw materials such as slag from metallurgical production and ash from combustion, it appears to be a more promising and more environmentally friendly material than conventional cement concrete. Considerable attention is paid to the bonding phase itself, but only a few works deal with the binder-aggregate interaction. With cement concrete, much more attention is paid to this issue. This paper deals with the possibility of observation using electron microscopy and the information that can be obtained by this method. The problems of sample preparation and difficulties in the course of our own observation are observed.

scholarly journals Interactions of Various types between Rock and Alkali-Activated Blast Furnace Slag

2017 ◽  
Vol 63 (1) ◽  
pp. 22-26
Author(s):  
Pavel Mec ◽  
Lucie Gembalová
Keyword(s):  
Mechanical Properties ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Ordinary Portland Cement ◽  
Raw Materials ◽  
Matrix Composition ◽  
Cement Binder ◽  
Alkali Activated Binders ◽  
Furnace Slag ◽  
Alkali Activated

Abstract Alkali-activated binders (AAB) are very intensively studied materials nowadays. Because of possible usage as secondary raw materials, they can be environmentally efficient. Intensive research is focused especially on binder matrix, composition and its structure. For industrial usage, it is necessary to work with some aggregate for the preparation of mortars and concretes. Due to different structures of alkali-activated binders, the interaction with the aggregate will be different in comparison to an ordinary Portland cement binder. This paper deals with the study of interactions between several types of rocks used as aggregate and alkali-activated blast furnace slag. The research was focused especially on mechanical properties of prepared mortars.

scholarly journals Alkali-Activated Binders Using Bottom Ash from Waste-to-Energy Plants and Aluminium Recycling Waste

2021 ◽  
Vol 11 (9) ◽  
pp. 3840 ◽  
Author(s):  
Alex Maldonado-Alameda ◽  
Jofre Mañosa ◽  
Jessica Giro-Paloma ◽  
Joan Formosa ◽  
Josep Maria Chimenos
Keyword(s):  
Bottom Ash ◽  
Physicochemical Characterization ◽  
Waste To Energy ◽  
Promising Alternative ◽  
Leaching Potential ◽  
Aluminium Recycling ◽  
Alkaline Activator ◽  
Alkali Activated Binders ◽  
Energy Plants ◽  
Alkali Activated

Alkali-activated binders (AABs) stand out as a promising alternative to replace ordinary Portland cement (OPC) due to the possibility of using by-products and wastes in their manufacturing. This paper assessed the potential of weathered bottom ash (WBA) from waste-to-energy plants and PAVAL® (PV), a secondary aluminium recycling process by-product, as precursors of AABs. WBA and PV were mixed at weight ratios of 98/2, 95/5, and 90/10. A mixture of waterglass (WG) and NaOH at different concentrations (4 and 6 M) was used as the alkaline activator solution. The effects of increasing NaOH concentration and PV content were evaluated. Alkali-activated WBA/PV (AA-WBA/PV) binders were obtained. Selective chemical extractions and physicochemical characterization revealed the formation of C-S-H, C-A-S-H, and (N,C)-A-S-H gels. Increasing the NaOH concentration and PV content increased porosity and reduced compressive strength (25.63 to 12.07 MPa). The leaching potential of As and Sb from AA-WBA/PV exceeded the threshold for acceptance in landfills for non-hazardous waste.

scholarly journals Alkali-Activated Zeolite 4A Granules—Characterization and Suitability Assessment for the Application of Adsorption

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 360
Author(s):  
Pauls P. Argalis ◽  
Laura Vitola ◽  
Diana Bajare ◽  
Kristine Vegere
Keyword(s):  
Compressive Strength ◽  
Raw Materials ◽  
Physical And Mechanical Properties ◽  
Morphological Properties ◽  
Solid Ratio ◽  
Suitability Assessment ◽  
Bet Analysis ◽  
Zeolite 4A ◽  
Compressive Strength Test ◽  
Alkali Activated

A major problem in the field of adsorbents is that binders (kaolin clay, bentonite) introduced to bind zeolites and ensure the needed mechanical strength, are not able to sorb gases like CO2 and N2, and decrease the overall adsorption capacity. To solve this problem, one of the pathways is to introduce a binder able to sorb such gases. Thus, in this study, the physical and mechanical properties of a novel binder based on metakaolin and its composite with zeolite 4A in the granular form were studied. Metakaolin was used as a precursor for alkali-activated binder, which was synthesized using an 8M NaOH activation solution. Raw materials were characterized using granulometry, X-ray diffraction (XRD), and differential thermal analysis (DTA); and final products were characterized using density measurements, a compressive strength test, XRD, Brunauer–Emmett–Teller (BET) analysis, and scanning electron microscopy (SEM). Alkali-activated metakaolin was found to be efficient as a binding material when data for morphological properties were analyzed. A relationship was observed—by increasing the liquid-to-solid ratio (L/S), compressive strength decreased. Zeolite granule attrition was higher than expected: 2.42% and 4.55% for ZG-0.8, 3.64% and 5.76% for ZG-1.0, and 2.73% and 4.85% for ZG-1.2, measured at 4 and 5 atmospheres, respectively.

scholarly journals Effect of CaSO4 Incorporation on Pore Structure and Drying Shrinkage of Alkali-Activated Binders

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1673 ◽  
Author(s):  
Hyeongmin Son ◽  
Sol Moi Park ◽  
Joon Ho Seo ◽  
Haeng Ki Lee
Keyword(s):  
Fly Ash ◽  
Pore Structure ◽  
Drying Shrinkage ◽  
Phase Changes ◽  
X Ray Diffraction ◽  
Activated Slag ◽  
Capillary Tension ◽  
Alkali Activated Binders ◽  
Internal Pore Structure ◽  
Alkali Activated

This present study investigates the effects of CaSO4 incorporation on the pore structure and drying shrinkage of alkali-activated slag and fly ash. The slag and fly ash were activated at a 5:5 ratio by weighing with a sodium silicate. Thereafter, 0%, 5%, 10%, and 15% of CaSO4 were incorporated to investigate the changes in phase formation and internal pore structure. X-Ray Diffraction (XRD), thermogravimetry (TG)/derivative thermogravimetry (DTG), mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and drying shrinkage tests were carried out to find the correlation between the pore structure and drying shrinkage of the specimens. The results showed that CaSO4 incorporation increased the formation of thenardite, and these phase changes affected the pore structure of the activated fly ash and slag. The increase in the CaSO4 content increased the pore distribution in the mesopore. As a result, the capillary tension and drying shrinkage decreased.

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