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Alkalicky aktivované materiály - výzkum, výroba a využití.

UTILISATION OF METALLURGICAL SLAGS AS RAW
MATERIAL BASIS FOR PREPARATION
OF ALKALI ACTIVATED MATERIALS

Využití metalurgických strusek jako suroviny pro výrobu alkalicky aktivovaných materiálů

Zdeněk Adolf, Jiří Bažan VŠB-Technical University of Ostrava

Faculty of Metallurgy and Materials Engineerig,
Department of Metallurgy

Abstract. Authors characterise in submitted paper blast furnace slags, steelmaking furnace slags and steelmaking ladle slags. The slags are characterised from the viewpoint of mass and place of their occurrence, of chemical and phase composition. Potential use of these slags for preparation of alkali activated materials requires continuing theoretical and technological research (share of crystalline and amorphous phases in dependence on chemical composition and speed of slag chilling, mechanical treatment of slags, etc.).

Keywords. Steelmaking slags, furnace slags, ladle slags, chemical composition, phase composition

EVALUATING THE POTENTIAL APPLICATION OF FLY ASH/ BLAST FURNACE SLAG GEOPOLYMER MATERIAL FOR INHIBITING ACID CORROSION, A COMPARATIVE STUDY

Hodnocení využívání geopolymerních materiálů z úletových popílků/vysokopecních strusek pro blokaci koroze kyselinami, porovnávací studie

Ali Allahverdi¹, FrantiŠek Škvára^2
1College of Chemical Engineering
Iran University of Science and Technology
²Department of Glass, Ceramics, and Inorganic Binders Institute of Chemical Technology, Czech Republic

Abstract. The response of hardened paste of a geopolymer cement to acid attack has been investigated and compared to that of ordinary Protland cement. The geopolymer cement was produced by activating a mixture of fly ash and blast furnace slag using a proportioned solution of NaOH and Na2SiO3. At relatively lower pH values (pH≤2), sulfuric acid is less corrosive than nitric acid because of the inhibition caused by gypsum crystals depositing on the acid-exposed surface or inside the corroding layer. The corrosion process very soon becomes diffusion controlled owing to the formation of relatively thick corroded layers. At relatively higher pH values (pH≥3) and for relatively short exposure time periods (≤ 90 days), mechanism of attack by sulfuric acid approaches that of nitric acid attack. The total rate of deterioration is more effectively controlled by the porosity and the nature of corroding phases than the protective effect of a relatively very thin corroded layer.

Keywords. Geopolymer cement, Acid resistance, Nitric acid, Sulfuric acid

GYPSUM-FREE PORTLAND CEMENT,
AN ALKALI-ACTIVATED MATERIAL SUITABLE
FOR ACID CORROSION PROTECTION

Bezsádrový portlandský cement, alkalicky aktivovaný materiál vhodný pro blokaci koroze kyselinami

Abstract. Investigation by scanning electron microscopy and X-ray energy dispersion measurements (X-ray line analyses) were performed on a number of 90-day corroded gypsum-free Portland cement and ordinary Portland cement paste specimens placed in nitric acid solutions of respective pH of 1, 2, and 3. The results obtained show that the hardened paste specimens of gypsum-free and ordinary Portland cements are corroded by exactly the same mechanism. The only difference between the two types of cement is the corrosion rate. The absence of crystalline formations, typical of hardened OPC paste, together with the high density and degree of dispersion of hydration products are responsible for a relatively higher acid resistance in gypsum-free Portland cement.

Keywords. Gypsum-free Portland cement, Nitric acid, Corrosion

INVESTIGATING THE SET AND STRENGTH BEHAVIOURS
OF BLAST - FURNACE SLAG BLENDED GEOPOLYMER
CEMENT BASED ON NATURAL POZZOLAN

Výzkum vlastností a pevností geopolymeru ze směsi vysokopecní strusky a přírodních pucolánů.

Ali Allahverdi, Mahshad Yazdanipour, Mohammad Hashemi College of Chemical Engineering, Iran University of Science and Technology

Abstract. The effect of some parameters including sodium oxide, ground granulated blast-furnace slag, and W/C-ratio on the most important engineering properties of natural pozzolan-based geopolymer cement systems were investigated. The properties studied include 28-day compressive strength and final setting time. The results obtained reveal that the most effective parameter on strength behaviour is sodium oxide concentration. The geopolymer cement system comprising of 5 wt% blast-furnace slag and 8 wt% Na2O with a W/C-ratio of 0.30 exhibits the highest 28-day compressive strength, i.e. 36 MPa, along with almost acceptable final setting time. Systems exhibiting the highest 28-day compressive strengths were characterized using laboratory techniques of FTIR and SEM.

Keywords. Geopolymer cement, Natural pozzolan

ALKALI-ACTIVATED SLAG CONCRETE FOR THE
PRODUCTION OF BUILDING ELEMENTS

Alkalicky aktivovaný struskový beton pro výrobu stavebních prvků

Vlastimil Bílek

ŽPSV A.S. Company, Brno, Czech Republic

Abstract. There are a number of scientific reports and laboratory experiments concerning slag alkaline concretes in the Czech Republic, but hardly any practical application. For practical application, various problems must be solved. They are, in particular, the optimum content and composition of the activator for an optimum setting and hardening time; the design of concrete for good workability; for the reaching of the smallest volume exchanges and the smallest efflorescence; for the maximum strength and a high durability. These problems are discussed in the present paper. Sodium water glass and/or NaOH and KOH were chosen as the optimum type of activator and the optimum ratio (Na2O+ K2O)/SiO2 were found. The testing of the setting time, XRD analyses and other methods were used for the characterisation of the mixes. The slag-alkaline concretes are designed as self compacting to achieve an easier introduction of these materials into practice. Some elements were produced from the AASC in 2006 (elements for cable pipe-lines, bases for transmission towers and lamp-posts, elements for shifts...). Also, some vibropressing elements were made. The paper contains also some experiences from pilot experiments with these elements.

Keywords. Slag alkaline concrete, limestone, setting, strengths, building elements

DEVELOPMENT, PROPERTIES AND PRODUCTION OF GEOPOLYMERS BASED ON SECONDARY RAW MATERIALS

Vývoj, vlastnosti a produkce geopolymerů na základě druhotných surovin

Oleg Bortnovsky¹, Karla Dvořáková¹, Pavel Roubíček²,
Jaroslav Boušek^2,Žaneta Průdková³, Pavel Baxa^4
1Research Institute of Inorganic Chemistry, Inc., Ústí nad Labem
²České lupkové závody, Inc., Nové Strašecí³Research Institute of Building Materials, JSC., Brno
⁴ Kerasil spol. Ltd., Praha

Abstract. Geopolymers are relatively new types of inorganic binders for production of building materials, which can partly substitute Portland cement used generally for these purposes. Application of geopolymer binders is also favorable from ecological point of view, because of considerably lower amount of carbon dioxide formed during production of geopolymer binders, in comparison with Portland cement, which enhances total amount of greenhouse gases in the atmosphere. One of main restrictive factors for spreading geopolymers is the cost of raw materials, including metakaolin, hydroxides and silicates of alkali metals. Possible way how to reduce the price of geopolymer binder is a utilization of secondary and waste raw materials, e.g. fly ash, slag or low-quality natural aluminosilicates. In the case of these raw materials, however, keeping chemical and mineralogical contents uniform is rather problematic. Within the scope of project FI-IM/079 “Application of residual and waste aluminosilicates for production of building materials on basis of inorganic polymers” utilization of aluminosilicate fly dusts from rotary kiln as a component for production of two-component geopolymer binder on their basis and sodium alkali activator was examined and verified in laboratory and pilot scale. This article is focused on introducing two-component geopolymer binders produced under the commercial name Baucis in České lupkové závody, Inc., on the methods of testing and the results of their mechanical properties, product manufacture qualities, temperature and chemical resistance and total costs of production. Applications of geopolymer binders are being developed in cooperation with Kerasil Comp., which manufactures objects of art and architectural details on the base of artificial stone, utilizing miscellaneous natural and artificial fillers, with various final product appearance and utility qualities.

Keywords. geopolymer, waste aluminosilicates, fly dust, sodium

alkali activator, two-component binder, durability

COMPOSITE MATERIALS WITH GEOPOLYMER MATRIX
PAST, PRESENT AND FUTURE

Kompozitní materiály s geopolymerní matricí – minulost, současnost a budoucnost.

Jiří Brandštetr, Jaromír Havlica, Tomáš Opravil Institute of Materials Cchemistry, Faculty of Chemistry, Brno University of Technology

Abstract. Recently, the utilization of different non-traditional cements and composites has been increasing. Geopolymers, analogous of natural minerals - zeolites, are produced by alkali activation of aluminosilicates. Preferably, industrial by-products (slags,fly ashes....) are used, which saves natural mineral resources, contributes to the increase of the productivity of materials using mineral "wastes" and decreasing of CO2 production, exhibiting thus ecological and economical effect. The alkali containing composites of similar type were produced as early as in ancient times and the still well-preserved buildings document very good long-term durability of this material.

Keywords. Alkali activation, aluminosilicates, zeolites, non-tradi-tional concrete, mineral composites.

INFLUENCE OF ALKALI ACTIVATION OF MARTIN SLAG
ON THE DURABILITY OF CONSTRUCTION BUILDING
PRODUCTS

Vliv alkalické aktivace strusky martinské na odolnost stavebních konstrukcí

V.I. Bratchun, A.N. Bachurin, N.P. Nagornaya

Donbass National Academy of Civil Engineering and Architecture, Makeyevka, Ukraine

Abstract. Experimental and theoretical studies are applied in determining the influence of alkali activation of Martin slag by addition small dosage of lime (Portland cement) on the durability of construction building products – waterproof slag brick and flags of road sidewalks. It has been determined that fine-grained particles of Martin slag with basicity modulus Мb = 1,9 possess binding properties which slowly showing up in the process of hydration during two years that is conditioned by low content of Portland clinker minerals in the composition of Martin slag and their crystalline structure. Inputting into the water-slag mixture of lime (Portland cement) is the effective method of alkali activation of Martin slag binding properties. Water solution of calcium hydrate Ca(OH)2 which isolate at the hydrolysis of С3S creates in concrete mixture high alkalinity with index of pH>12. The cathions Са²⁺ destroy a shell of Аl(OH)3 and Si(OH)3 on the hydrated areas of slag. As a result, calcium silicate hydrate (C-S-H) gel with low Ca/Si ratio as well as hexagon double-calcium hydroaluminate and hydrogelenyt are generated in pore space of concrete mixture. The crystallization microstructure of slag concrete is formed.

Keywords. Martin slag, binding properties, compressive strength, syneresis, microsrtucture

THE INFUENCE OF CLINOPTILOLITE ZEOLITES ON THE PROPERTIES OF ALKALI ACTIVATED SLAG PASTES

Vliv klinoptiolitových zeolitů na vlastnosti alkalicky aktivovaných struskových směsí

Witold Brylicki¹, Jan Małolepszy¹, Stanisław Stryczek², Łukasz Kotwica¹

¹Department of Building Materials Technology, Faculty of Materials Sciences and Ceramics, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland ²Department of Drilling and Geoengineering, Faculty of Drilling, Oil and Gas, AGH University of Science and Technology, Al. Mickiewicza 30, 30-059 Kraków, Poland

Abstract. Alkali activated slag slurries for boreholes cementing were modified with natural zeolite – clinoptilolite. Three different activators: ordinary portland cement, soda and blended activator (cement + soda) were used. In present paper results of investigations on the influence of clinoptilolite modification of alkali activated slag slurries are described. Natural clinoptilolite was introduced to alkali activated slag pastes in quantities between 1 and 5 % in respect to dry ingredients mass. Properties of pastes both in fresh and hardened state were examined. Microstructure studies were also conducted. Addition of natural clinoptilolite slightly changed the workability of slurries. It seriously influenced setting behaviour of the slurries. Details are presented in the article. Casson model was found as the best model to describe the rheological properties of fresh slurries. Clinoptilolite causes reduction in 7 days strength (except compressive strength of soda activated slurries).

Keywords. Cclinoptilolite, alkali–activated slag, drilling operations,

durability, zeolites

THE SUITABILITY OF DIFFERENT CLAY RESOURCES
IN RESPECT TO FORM GEOPOLYMERIC BINDERS

Vhodnost různých jílových zdrojů ve smyslu utváření geopolymerních pojiv

A. Buchwald, M. Hohmann, Ch. Kaps
Bauhaus-University Weimar, Germany

Abstract. So called geopolymers or geopolymeric binders and cements are made by means of an alkaline activation of materials reactive in this respect. Such material has to consist of a certain amount of silicate and aluminate phases which can be dissolved by the alkaline medium. In the consequence stable polymeric networks of alumosilicates will be formed. Metakaolins and alumo-siliceous fly ashes, in particular, have by now achieved noteworthy significance. The search for alternative low cost or high available materials may lead among other things to “normal clays”. This material is widely available all over the world and may show certain reactivity after a thermal activation process. This investigation focuses the influence of the clay composition on the geopolymer performance. Clays with different kind and amount of the clay mineral (illite, montmorillonite, and kaolinite) as well as side minerals (calcite and dolomite) were investigated.

Keywords. Thermally activated clays, geopolymers, calcite, dolo-mite

LIFE CYCLE ANALYSIS INCORPORATED DEVELOPMENT OF GEOPOLYMER BINDER - EXPLAINED IN THE SPECIAL

Analýza životního cyklu geopolymerního pojiva – ukázka na speciálním příkladu: kyselinám odolný nátěr

EXAMPLE: ACID RESISTANT COATING

A. Buchwald¹, M. Weil², K. Dombrowski^3
1Bauhaus-University Weimar, Germany;
²Forschungszentrum Karlsruhe, Germany;
³Technical University Bergakademie Freiberg, Germany

Abstract. In the field of building materials development environmental aspects become more and more important. Besides reducing energy consumption and CO2 emission in the cement production process efforts are being made to employ more secondary and waste materials. Another option is the development of alternative binders, such as alkali-activated materials or geopolymers, respectively, and which are labelled as environmentally friendly in literature. The results presented arise from a project that attempts to establish a connection between the raw material screening and the mixture design, as well as the binder optimization of geopolymers in terms of a defined application. The selection and the evaluation of the raw materials are carried out with the consideration of all three aspects: technical, ecological, and economical. This step of material selection is followed by the material development phase incorporating e.g. LCA and LCC and leading to the generation of a performance profile of every single optimised mixture in accordance with the special application field. The data of the application field “acid resistant coating” are presented.

Keywords. Acid resistant coating, geopolymer, alkali activation, cost analysis, Life Cycle Assessment, Multi Criteria Decision Analyses

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