scholarly journals RESIDUAL PROPERTIES OF FIBER-REINFORCED REFRACTORY COMPOSITES WITH A FIRECLAY FILLER

2016 ◽  
Vol 56 (1) ◽  
pp. 27 ◽  
Author(s):  
Marcel Jogl ◽  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Jaroslava Koťátková ◽  
Petr Konvalinka
Keyword(s):  
Bulk Density ◽  
Thermal Loading ◽  
Ceramic Powder ◽  
High Energy ◽  
Mechanical Parameters ◽  
Binder System ◽  
Basalt Fibers ◽  
Residual Properties ◽  
Aluminous Cement ◽  
Residual Values

The aim of our study was to develop a composite material for industrial use that is resistant to the effect of high temperatures. The binder system based on aluminous cement was modified by adding finely-ground ceramic powder and metakaolin to reduce costs and also to reduce adverse effects on the environment due to high energy consumption for cement production. Additives were applied as a partial aluminous cement replacement in doses of 10, 20 and 30% by weight. The composites were evaluated on the basis of their mechanical properties and their bulk density after gradual temperature loading. The influence of basalt fibers and modifications to the binder system were studied at the same time. Basalt fibers were applied in doses of 0.5% and 2.0% by volume. The results confirmed the potential of the mineral additives studied here for practical applications, taking into account the residual mechanical parameters after thermal loading. The addition of ceramic powder reduced the bulk density by 5% for each 10% of cement substitution, but the residual values were very similar. The bulk density and the compressive strength were reduced when basalt fibers were applied, and the flexural strength was significantly increased in proportion to the fiber dosages. Metakaolin seems to be a more suitable additive than the ceramic powder that was applied here, because there was a significant increase in the mechanical parameters and also in the residual values of all properties that were studied.

scholarly journals Physical and Mechanical Properties of Composites Made with Aluminous Cement and Basalt Fibers Developed for High Temperature Application

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Marcel Jogl ◽  
Petr Konvalinka
Keyword(s):  
Mechanical Properties ◽  
Flexural Strength ◽  
Fracture Energy ◽  
Bulk Density ◽  
Thermal Loading ◽  
Ceramic Powder ◽  
Physical And Mechanical Properties ◽  
Partial Replacement ◽  
Basalt Fibers ◽  
Aluminous Cement

Present paper deals with the experimental study of the composition of refractory fiber-reinforced aluminous cement based composites and its response to gradual thermal loading. Basalt fibers were applied in doses of 0.25, 0.5, 1.0, 2.0, and 4.0% in volume. Simultaneously, binder system based on the aluminous cement was modified by fine ground ceramic powder originated from the accurate ceramic blocks production. Ceramic powder was dosed as partial replacement of used cement of 5, 10, 15, 20, and 25%. Influence of composition changes was evaluated by the results of physical and mechanical testing; compressive strength, flexural strength, bulk density, and fracture energy were determined on the different levels of temperature loading. Increased dose of basalt fibers allows reaching expected higher values of fracture energy, but with respect to results of compressive and flexural strength determination as an optimal rate of basalt fibers dose was considered 0.25% in volume. Fine ground ceramic powder application led to extensive increase of residual mechanical parameters just up to replacement of 10%. Higher replacement of aluminous cement reduced final values of bulk density but kept mechanical properties on the level of mixtures without aluminous cement replacement.

Influence of High-Temperature on Polycarboxylate Superplasticizer in Aluminous Cement Based Fibre Composites

2014 ◽  
Vol 982 ◽  
pp. 125-129 ◽  
Author(s):  
Marcel Jogl ◽  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Jaroslava Koťátková
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Flexural Strength ◽  
High Temperatures ◽  
Thermal Loading ◽  
Experimental Program ◽  
Basalt Fibers ◽  
Fibre Composites ◽  
Aluminous Cement ◽  
Properties Of Composites

This paper summarizes the results of an experimental program aimed at investigating of the mechanical properties of composites based on aluminous cement for high-temperature applications and deal with the influence of high-thermal loading on polycarboxylate superplasticizing (PCSP) additive contained in the composite. The intent of this examination was caused by the suspicion that the action of high-temperatures can lead to burnout of the PCSP additive and thus subsequently affecting the mechanical properties of the final composite. Silica composites based on Portland cement and silica aggregates are not able to resist the effects of high-temperatures [1]. For high-temperature composites was therefore used aluminous cement Secar®71 (Lafarge S.A.) in combination with crushed basalt aggregates of fraction 0/4 and 2/5 mm. The flexural strength was greatly improved thanks combinations of basalt fibers with lengths of 6.35 mm and 12.7 mm. The values ​​of flexural strength and compression strength were investigated on samples dried at temperature 105 °C or loaded for 180 minutes with high-temperature of 600 °C or 1 000 °C.

Utility of Air-Entraining Additive in the Development of Lightweight Alumina-Based Refractories

2020 ◽  
Vol 975 ◽  
pp. 147-152
Author(s):  
Marcel Jogl ◽  
Pavel Reiterman
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
High Temperatures ◽  
Building Materials ◽  
Chemical Engineering ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Aluminous Cement ◽  
The Many ◽  
The Impact

The paper presents the impact of doses of an air-entraining additive on the mechanical properties of a composite based on aluminous cement. The presented data have been selected from the authors’ most recent research, which supports an economic development of a lightweight composite with the ability to withstand elevated temperatures of up to 1000 °C. The interest in the behaviour of concrete at high temperatures mainly results from the many cases of fires taking place in buildings, high-rises, tunnels, and drilling platform structures. Operation at high temperatures is also of fundamental importance to many major sectors of industry, including material production and processing, chemical engineering, power generation and more. Concrete has a great intrinsic behaviour when exposed to fire, especially when compared to other building materials. However, its fire resistance should not be taken for granted and proper structural fire protection is certainly necessary, e.g. in the form of high-temperature barriers. For the purposes of this experiment, the specimens were composed of cement paste and an air-entraining additive dosage between 2 – 10 % by weight of the cement dose. The properties of investigated specimens, dried at a temperature of 105 °C, were compared with each other. Values of compressive strength, flexural strength, and bulk density are measured in this work. The purpose was to evaluate the effects of the air-entraining agent on the workability of a fresh mixture, its bulk density, and mechanical properties after drying. In the case of a mixture with added short basalt fibres, the effects after high thermal loading were also evaluated. The proposed composites with air-entraining additive over 8 % shown the values of bulk density below 1800 kg/m3, along with the satisfactory strength results.

Refractory Composites with Mineral Additive

2015 ◽  
Vol 824 ◽  
pp. 49-53
Author(s):  
Marcel Jogl ◽  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Filip Vogel ◽  
Petr Konvalinka
Keyword(s):  
Thermal Loading ◽  
Binder System ◽  
Practical Utilization ◽  
Mineral Addition ◽  
Mineral Additive ◽  
Good Potential ◽  
New Type ◽  
Aluminous Cement ◽  
Supplementary Material ◽  
Refractory Composites

Present paper deals with experimental study of refractories manufactured with environmentally friendly materials. Performed research was focused on the development of new type of high temperature resistant composites with mineral addition applied as cement supplementary material. To reach suitable resistance to temperatures was chosen binder system based on aluminous cement which was modified by metashale. Developed composites went through the gradual thermal loading and residual mechanical and basic physical properties were investigated. Realized program confirmed good potential for practical utilization of metashale as an aluminous cement replacement. Present research offer an interesting way of reducing of costs and negative environmental impacts.

Mechanical and Fracture Characteristics of Refractory Concrete after the Action of Various Temperature Loading

2018 ◽  
Vol 760 ◽  
pp. 102-107
Author(s):  
Ondřej Holčapek
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Compressive Strength ◽  
Dynamic Modulus ◽  
Thermal Loading ◽  
Refractory Concrete ◽  
Fracture Characteristics ◽  
Residual Properties ◽  
Aluminous Cement ◽  
Refractory Composite

This article deals with the experimental investigation of residual mechanical properties of refractory composite after the action of various thermal loading. Specimens with dimension 40 × 40 × 160 mm were produced from composite containing basalt fibres and aggregate, aluminous cement and metakaolin. Different group of specimens were exposed to various temperatures 105 °C, 200 °C, 300 °C, 400 °C, 500 °C and 600 °C for three hours. Different temperature caused various changes in chemical composition of concrete that can result into decrease of mechanical properties. Bulk density, flexural strength, compressive strength, fracture energy and dynamic modulus of elasticity were investigated after each type of thermal loading. After the action of 600 °C all investigated residual properties achieved lowest values. Based on performed experiments we can conclude that the main decrease of mechanical properties take place after the action of 400 °C.

scholarly journals Development of Composite for Thermal Barriers Reinforced by Ceramic Fibers

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Ondřej Holčapek ◽  
Jaroslava Kot'átková ◽  
Pavel Reiterman
Keyword(s):  
Flexural Strength ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Ceramic Powder ◽  
Hydrothermal Condition ◽  
Optimal Dosage ◽  
Ceramic Fibers ◽  
Cement Replacement ◽  
Hydrothermal Curing ◽  
Aluminous Cement

The paper introduces the development process of fiber-reinforced composite with increased resistance to elevated temperatures, which could be additionally increased by the hydrothermal curing. However, production of these composites is extremely energy intensive, and that is why the process of the design reflects environmental aspects by incorporation of waste material—fine ceramic powder applied as cement replacement. Studied composite materials consisted of the basalt aggregate, ceramic fibers applied up to 8% by volume, calcium-aluminous cement (CAC), ceramic powder up to 25% by mass (by 5%) as cement replacement, plasticizer, and water. All studied mixtures were subjected to thermal loading on three thermal levels: 105°C, 600°C, and 1000°C. Experimental assessment was performed in terms of both initial and residual material properties; flow test of fresh mixtures, bulk density, compressive strength, flexural strength, fracture energy, and dynamic modulus of elasticity were investigated to find out an optimal dosage of ceramic fibers. Resulting set of composites containing 4% of ceramic fibers with various modifications by ceramic powder was cured under specific hydrothermal condition and again subjected to elevated temperatures. One of the most valuable benefits of additional hydrothermal curing of the composites lies in the higher residual mechanical properties, what allows successful utilization of cured composite as a thermal barrier in civil engineering. Mixtures containing ceramic powder as cement substitute exhibited after hydrothermal curing increase of residual flexural strength about 35%; on the other hand, pure mixture exhibited increase up to 10% even higher absolute values.

scholarly journals Influence of mechanical activation of AL2O3 on synthesis of magnesium aluminate spinel

2004 ◽  
Vol 36 (2) ◽  
pp. 73-79 ◽  
Author(s):  
Zhang Zhihui ◽  
LI. Nan
Keyword(s):  
Grain Size ◽  
Mechanical Activation ◽  
Bulk Density ◽  
Milling Time ◽  
High Energy ◽  
Magnesium Aluminate ◽  
Reaction Sintering ◽  
Air Atmosphere ◽  
Energy Ball ◽  
Analytical Reagent

Magnesium aluminate (MA) spinel is synthesized by reaction sintering from alumina and magnesia. The effects of mechanical activation of Al2O3 on reaction sintering were investigated. Non-milled a - Al2O3 and a - Al2O3 high-energy ball milled for 12h, 24h and 36h were mixed with a MgO analytical reagent according to the stoichiometric MA ratio, respectively and pressed into billets with diameters of 20mm and height of 15mm. The green-body billets were then sintered at high temperature in an air atmosphere. The results show that bulk density, relative content of MA and grain size of MA increase with increasing high-energy ball milling time of Al2O3. However prolonged milling time over 24h has a small beneficial effect on the densification of MA. Bulk density and grain size of a sample of a- Al2O3 milled for 24h are 3.30g/cm3 and 4-5 mm, respectively.

Fracture and Mechanical Properties of Fire Resistant Fibre Composites Containing Fine Ground Ceramic Powder

2014 ◽  
Vol 897 ◽  
pp. 192-195 ◽  
Author(s):  
Pavel Reiterman ◽  
Ondřej Holčapek ◽  
Filip Vogel ◽  
Marcel Jogl ◽  
Jaroslava Koťátková
Keyword(s):  
Renewable Resources ◽  
Thermal Load ◽  
High Performance ◽  
Building Materials ◽  
Bending Strength ◽  
Ceramic Powder ◽  
Experimental Program ◽  
Maximum Efficiency ◽  
Fibre Composites ◽  
Aluminous Cement

Significant advances in the field of building materials leads to increasingly frequent enforcement of these high performance materials in real constructions. Efforts to maximize the efficient use of non-renewable resources and especially energy-intensive materials lead to efforts to achieve maximum efficiency and usability [. Paper presents results of an experimental program focused on development of fire-resistance composites based on aluminous cement with fine ground ceramic powder (FGCP). Studied fibre composites were loaded by temperature 600 °C and 1000 °C. The influence of applied thermal load on composites was evaluated by means of fracture energy, compressive strength, bending strength and modulus of elasticity in bending.

Creep Relaxation Behavior of High-Energy Piping

2000 ◽  
Vol 122 (4) ◽  
pp. 488-493 ◽  
Author(s):  
Raymond K. Yee ◽  
Marvin J. Cohn
Keyword(s):  
Stress Relaxation ◽  
Thermal Loading ◽  
Elevated Temperatures ◽  
Three Dimensional ◽  
Creep Damage ◽  
High Energy ◽  
External Loading ◽  
Piping System ◽  
Dead Weight ◽  
Piping Systems

The analysis of the elastic stresses in high-energy piping systems is a routine calculation in the power and petrochemical industries. The American Society of Mechanical Engineers (ASME) B31.1 Power Piping Code was developed for safe design and construction of pressure piping. Postconstruction issues, such as stress relaxation effects and selection of maximum expected creep damage locations, are not addressed in the Code. It has been expensive and time consuming to evaluate creep relaxation stresses in high energy piping systems, such as main steam and hot reheat piping. After prolonged operation of high-energy piping systems at elevated temperatures, it is very difficult to evaluate the redistribution of stresses due to dead weight, pressure, external loading, and thermal loading. The evaluation of stress relaxation and redistribution is especially important when nonideal conditions, such as bottomed-out or topped-out hangers, exist in piping systems. This paper uses three-dimensional four-node quadrilateral shell elements in the ABAQUS finite element code to evaluate the time for relaxation and the nominal relaxation stress values for a portion of a typical high-energy piping system subject to an ideally loaded hanger or to an overloaded hanger. The stress relaxation results are evaluated to suggest an approximation using elastic stress analysis results. [S0094-9930(00)01304-4]

High Temperature Composite of Aluminous Cement with Addition of Metakaolin and Ground Bricks Dust

2013 ◽  
Vol 486 ◽  
pp. 406-411 ◽  
Author(s):  
Ondřej Holčapek ◽  
Pavel Reiterman ◽  
Petr Konvalinka
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Temperatures ◽  
Raw Materials ◽  
Cement Composites ◽  
Basalt Fibers ◽  
Aluminous Cement ◽  
The Common ◽  
Temperature Exposure ◽  
Sufficient Strength

The following article deals with the study of mechanical properties of aluminous cement composites exposure to high temperatures. The newly designed mixtures that resist the action of high temperatures 1000 °C find their application in various fields of industrial production or in the form of fire wall for protection bearing structures. All the mechanical properties such as compressive strength and tensile strength in bending were measured on samples 160x40x40 mm. These samples were exposed to temperatures 600 °C and 1000 °C and one group of samples was reference and stayed in laboratory condition. Aluminous cement unlike the common Portland cement keeps sufficient strength even after high temperature exposure. For ensuring required ductility the basalt fibers were added to the mixture. In an effort to use of secondary raw materials as a replacement for cement as well as a suitable binder was used metakaolin and ground brick dust. Very convenient characteristics of these components are their latent hydraulic potential that makes interesting hydration products.

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