Sustainable Construction Materials and Technologies (SCMT), 2016
This paper deals with the experimental study of aluminous cement-based composites with applicatio... more This paper deals with the experimental study of aluminous cement-based composites with applications of granulated ceramic fibers and different types of aggregates. The studied composites were developed for high temperature applications, thus the response to gradual temperature loading was carried out in the experimental program (up to 600 °C and 1000 °C). An evaluation was performed in order to determine the final and residual values of the bulk density and mechanical propertiesflexural and compressive strength. Used granulated ceramic fibers were applied in doses of 0.5 %, 1.0 %, 2.0 %, 4.0 % and 8.0 % by volume. The influence of aggregate types was investigated for each dosage of fibers. Natural basalt, crushed fireclay, and expanded glass were selected as a fillers of constant volume for the mixtures. The results obtained confirmed the essential impact of fiber application, predominantly on the increase of flexural strength. However, flexural strength was not increased linearly with fiber dosage. An application dose of 8.0 % of fibers by volume was not an efficient solution, because of only minimal improvement. Additionally, an extreme dosage of ceramic fibers reduced the values of bulk density and the proportional values of compressive strength for all studied combinations of aggregates. The optimal dosage seems to be 4.0 % by volume. Bulk density was reduced after the temperature loading by 5 %, resp. 10 % due to microstructural changes, but mixtures with ceramic fibers exhibited slightly better stability. Generally, the best resistance to high temperature was reached with mixtures with fireclay aggregate, as was expected. The application of expanded glass as a filler significantly contributed to the reduction of the bulk density on the level of lightweight composites, which is often required. It can be concluded that the application of granulated ceramic fibers essentially increased the subject properties, as well as the resistance to high temperature of developed composites.
This paper describes the results and an example of the use of secondary materials in concrete for... more This paper describes the results and an example of the use of secondary materials in concrete for application to practice, which were obtained from a project in cooperation with the University CTU in Prague and company Hochtief CZ a.s. Extensive experiments were carried out in the project, where the ideal concrete with admixtures was sought. Prefabricated part made of concrete composite with minimized cement content was realized, which replaced binder based on the use of secondary materials that apply modified energy by-products. It is a hydraulic ternary binder, which replaces cement in the amount of 50% compared to the original production formulation of concrete. The prefabricated part uses recycled materials or secondary raw materials of the by-product type in combination with the reduction of energy intensity, which is primarily associated with the production of cement. The implementation of the operational test of the production of the basic slab element for the prefabricated part was carried out at the concrete plant of the company Chynovska 714, 391 11 Plana nad Luznici of the company Hochtief CZ a.s., on 2 October 2019 with the possibility of further use for soundproof walls waste rubber in a thickness of 20 mm, with resistance to aggressive environments and service life of 30 years. The new implementation has a positive impact on the environment while achieving a lower carbon footprint and at the same time the use of part of materials that otherwise end up as waste, the implementation leads to CO2 reduction and actively supports the Waste Management Plan of the Czech Republic (WMP) for the period 2015-2024.
Paper deals with the assessment of practical utilization of granulated cable plastic waste (GCPW)... more Paper deals with the assessment of practical utilization of granulated cable plastic waste (GCPW) for the production of stabilized soil layers in transport engineering. The main goal of the experimental work was the evaluation of the influence of GCPW on mechanical properties of soil stabilization based on the fluidized fly ash. Mechanical properties were investigated using standard procedures in soil mechanics. GCPW was dosed as a partial replacement of fluidized fly ash up to 30 %. It was concluded, that the studied level of replacement performs critical level, additional increasing of GCPW would lead to a decline of required mechanical properties. Besides, replacement by studied waste material caused lower values of the bulk density.
SPECIAL CONCRETE AND COMPOSITES 2020: 17th International Conference, 2021
The objective of the research is to investigate the mechanical properties of the newly designed l... more The objective of the research is to investigate the mechanical properties of the newly designed lightweight cement-based refractory composite before and after high-thermal loading. To produce convenient refractory material was chosen binder system based on aluminous cement. Lightweight composite/concrete (LWC) is an effective and easy way to deduce a dead load of the structure. Besides, LWC is mainly formed by porous materials and high content of air bubbles. That's the reason why its coefficients of heat conduction and linear expansion is smaller than that of ordinary concrete. Therefore, LWC provides better thermal conservation, high-temperature resistance, and fire endurance. The designed composite in this paper content a lightweight aggregate Liaver in combination with chopped basalt fibers and air-entraining additive to secure the necessary values of bulk density, and was therefore classified as a lightweight composite. The short fibers are also applied for the purpose to support the composite resistance to inner tension caused by high thermal loading and achieve better residual properties.
The article is aimed at the description of design, 3D modelling and simulation of technology for ... more The article is aimed at the description of design, 3D modelling and simulation of technology for processing and fabrication of the formwork for complex concrete structures. The process of fabrication of complex-shaped elements from the special composite concrete mixture with application of several sophisticated software, technologies and industrial robot KUKA Agilus is also described in this work. The RHWC (Robotic Hot Wire Cutter) technology fully matches the prior aspects of the Industry 4.0 concept. The study consists of four parts. The first part simplified describes the mathematical apparatus of parametric modelling for complex concrete surfaces in Rhino 6.0 software. During the research two figures was precisely designed and modelled. The second part is aimed at the description of contemporary architectural trends in complex concrete structures manufacturing, modelling and analysis of ability to implement the complex-shaped surfaces with the RHWC technology. The third part des...
Proceedings of the 4th Brazilian Conference on Composite Materials, 2018
This article is focusing on comparison of plasticizing and air-entraining additives and their eff... more This article is focusing on comparison of plasticizing and air-entraining additives and their effect on mechanical properties of composite based on aluminous cement. Achieved results supposed to help during the development of lightweight composite able to withstand temperatures over 1000 °C and reduce heat transfer from a high temperature source, either by direct contact (conduction/convection) or via radiation. Operation at high temperature is of fundamental importance to many major sectors of industry, including material production and processing, chemical engineering, power generation and more. Objective is to achieve competitive performance with competitive life cycle costs. Maximum material efficiency and minimum manufacturing and operating costs are key factors in meeting this objective. Selection of a materials with sufficient economic conditions for a particular application must take account of many factors. For the purpose of this experiment, specimens were created from cement paste and different dosage of chopped carbon fibres. Experimental investigation underwent two series of samples different in the type of used additives. First series contains plasticizing additive, second series contains air-entraining additive. The purpose was to determine the different effect on the workability of fresh mixture, bulk density and mechanical properties. The strength of samples was measured after exposure to high temperatures of 600 °C and 1000 °C. The residual properties were compared between each other and also to samples dried at the temperature of 105 °C. Obtained results revealed the level of influence of mentioned additives on the composition of studied refractory composite.
The paper presents the impact of doses of an air-entraining additive on the mechanical properties... more 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...
The results of an experimental investigation of the influence of chopped alumina-silica bulk fibe... more The results of an experimental investigation of the influence of chopped alumina-silica bulk fibers on residual mechanical properties of lightweight cement-based composites for high temperature application are obtained. The matrix of studied specimens is based on aluminous cement, because of its sufficient temperature resistance over 1000 °C. Thermal ceramic bulk fiber offer a maximum temperature range of between 1200° to 1500 °C. They also provide excellent chemical stability and resistance to chemical attack. If wet by oil or water, thermal and physical properties will be fully restored after drying. The benefits of using ceramic bulk fibers were evaluated by the results of physical and mechanical testing; compressive strength, flexural strength and bulk density were determined on the different levels of temperature loading. The prismatic specimens, having dimensions of 40×40×160 mm3, are cured 28 days in humid environment and after that time dried and subjected to temperatures of...
The aim of our study was to develop a composite material for industrial use that is resistant to ... more 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 dens...
Cement is an extremely energy consuming material and its production leads to the emission of a va... more Cement is an extremely energy consuming material and its production leads to the emission of a vast amount of greenhouse gases. Cementitious concrete is a universal building material, which is used for the production of various structural elements. The paper describes the problem of cement production and its impact on the environment. This research deals with application of aluminous cement as binder component for the manufacture of refractory composites and with possibilities of further utilization of environmentally friendly materials with pozzolanic properties as a partial replacement of used aluminous cement. These materials are originating as waste in the building industry or by the recycling of cast-off materials. To reduce the costs and adverse effects on the environment was the binder system modified by finely ground ceramic powder and metakaolin. The experimental results present the values of flexural and compressive strength investigated on a series of composite specimens with dimensions of 40×40×160 mm3 and 10, 20 and 30 % of cement replacement. The aim of the present work is to apply the mentioned pozzolanic materials and reach the suitable composite with the sufficient heat resistance and residual mechanical parameters after gradual temperature loading.
Development of new composite materials is the worldwide extremely progressive branch of engineeri... more Development of new composite materials is the worldwide extremely progressive branch of engineering activity. Composite materials are applied in many industries. The principle of composite materials is a combination of different materials providing an entirely new material with specific properties. Fiber-reinforced composites rank to the most frequently used composites because of their suitable mechanical properties. There were studied mechanical properties of fibre reinforced cementitious composites (FRCC) exposed to high temperatures of 600 °C and 1000 °C in the paper. For the production of refractory FRCC were used aluminous cement Secar®71 with 70 % of Al2O3. Various composites differed in the used type of fibers - basalt, carbon and ceramic fibres were applied in doses of 2 % by volume. For the experimental program were prepared prismatic specimens with the total dimensions of 40 × 40 × 160 mm3 and cured for 28 days in humid environment. Residual bulk density, flexural and comp...
The main aim of this contribution lies in the description of mechanical properties fiber cement c... more The main aim of this contribution lies in the description of mechanical properties fiber cement composites after exposure to high temperatures. Destructive and non-destructive methods were used to investigate the influence of heat loading. The effect of refractory binder compared to common Portland cement binder was observed. Widespread non-destructive testing method can describe the changes of mechanical properties due to influence of external load e.g. high temperature at the level of 1000 °C. The tensile strength and compressive strength were investigated on specimens 40 x 40 x 160 mm. Before these destructive tests dynamic modulus of elasticity and tentative compressive strength were provided.
This paper summarizes the results of an experimental program aimed at investigating of the mechan... more 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...
This paper describes the application of lightweight aggregate (LWA) in the creation of fire resis... more This paper describes the application of lightweight aggregate (LWA) in the creation of fire resistant composite. The effort of the project is the preparation of a light refractory material with good mechanical properties, which would reach technically economical solutions. We initially chose as lightweight aggregate Liaver, which in combination with chamotte aggregate represent the filler of composite. The following observations were focused on partial replacement of binding components with brick dust and its influence on the mechanical properties of the composite. After design process, test composite specimens were produced to determine hardened properties at standard age. On the 28 day were all the mixtures exposed to 105, 600 and 1000 °C. Lastly, the flexural and compressive strength tests were performed on the composite specimens to identify high temperature effect comparing to strength test results obtained from standard laboratory conditions.
Following article deals with experimental investigation of elevated temperatures influence on mec... more Following article deals with experimental investigation of elevated temperatures influence on mechanical properties of refractory cement composite, which seems to be very progressive and interesting field of material science. Specimens 40 x 40 x 160 mm3 were exposed to 600 °C and 1000 °C for three hours. Using of aluminous cement, in this case Secar®71 with70 % of Al2O3, means the basic premise for refractory composites. Natural crushed basalt aggregate of two fractions 0-4 mm and 2-5 mm works as filler. Metakaolin MefistoL05 in amount 225 kg/m3 represents the fine filler, commonly used in refractory concrete production. Ceramic fibers or combination of two lengths of basalt fibers significantly improve the flexural characteristics. The goal of this research is to quantified influence of basalt fibers and ceramic fibers on flexural strength, compressive strength and bulk density of cement composite in high temperature conditions.
Present paper deals with experimental study of refractories manufactured with environmentally fri... more 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.
Computational Methods and Experimental Measurements XVII, 2015
This paper deals with the experimental study of the composition of special highperformance Portla... more This paper deals with the experimental study of the composition of special highperformance Portland cement based composites and their resistance to de-icing salt scaling. The aim of this was to evaluate the impact of pozzolanic additiveburnt clay, the application of which is documented by several research works. Studied composites are formulated as fine-grain high performance concrete with high dose of Portland cement and silica fume and very low rate of water-cement ratio to ensure reduced permeability. Burnt clay was applied as cementitious supplementary material to reduce the environmental impact of concrete mixtures and to obtain suitable microstructure. Portland cement replacement by the above mentioned additive was gradually elevated just up to the rate of 60% of Portland cement weight. Investigation of scaling resistance was complemented by measuring surface water absorption and determination of flexural and compressive strength which exceeded the level of 100 MPa for studied mixtures. Mechanical properties were not extensively affected by burnt clay additive, but the essential impact of studied pozzolanic material was noticeable in the case of scaling and absorption tests, which means processes regulated by permeability. In this point of view, optimum rate of replacement by burnt clay seems to be about 30% of Portland cement weight. A mixture with optimal composition exhibited increased durability by more than 50% to reference mixture. Application of burnt clay contributed to good potential for practical use for all tested properties with significant production energy savings.
Significant advances in the field of building materials leads to increasingly frequent enforcemen... more 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.
Fundamental tasks of material engineers are the application of materials, which can be manufactur... more Fundamental tasks of material engineers are the application of materials, which can be manufactured from the less valuable materials with conservation or increasing of final properties, predominantly higher strength and durability. Present paper contributes to the category of experimental research of special composites development. Article describes the application of secondary raw materials for the production of special fibre-reinforced composite for high temperature application. These secondary raw materials are arising by the recycling of waste produced in the building industry or by the recycling of cast-off materials. Aim of performed experimental program was to prepare lightweight refractory materials based on aluminous cement with sufficient mechanical properties. Application of secondary raw materials could be interesting solution with environmental benefits. Investigation of new type of fire resistant composites were realized on the base mechanical properties determination ...
Sustainable Construction Materials and Technologies (SCMT), 2016
This paper deals with the experimental study of aluminous cement-based composites with applicatio... more This paper deals with the experimental study of aluminous cement-based composites with applications of granulated ceramic fibers and different types of aggregates. The studied composites were developed for high temperature applications, thus the response to gradual temperature loading was carried out in the experimental program (up to 600 °C and 1000 °C). An evaluation was performed in order to determine the final and residual values of the bulk density and mechanical propertiesflexural and compressive strength. Used granulated ceramic fibers were applied in doses of 0.5 %, 1.0 %, 2.0 %, 4.0 % and 8.0 % by volume. The influence of aggregate types was investigated for each dosage of fibers. Natural basalt, crushed fireclay, and expanded glass were selected as a fillers of constant volume for the mixtures. The results obtained confirmed the essential impact of fiber application, predominantly on the increase of flexural strength. However, flexural strength was not increased linearly with fiber dosage. An application dose of 8.0 % of fibers by volume was not an efficient solution, because of only minimal improvement. Additionally, an extreme dosage of ceramic fibers reduced the values of bulk density and the proportional values of compressive strength for all studied combinations of aggregates. The optimal dosage seems to be 4.0 % by volume. Bulk density was reduced after the temperature loading by 5 %, resp. 10 % due to microstructural changes, but mixtures with ceramic fibers exhibited slightly better stability. Generally, the best resistance to high temperature was reached with mixtures with fireclay aggregate, as was expected. The application of expanded glass as a filler significantly contributed to the reduction of the bulk density on the level of lightweight composites, which is often required. It can be concluded that the application of granulated ceramic fibers essentially increased the subject properties, as well as the resistance to high temperature of developed composites.
This paper describes the results and an example of the use of secondary materials in concrete for... more This paper describes the results and an example of the use of secondary materials in concrete for application to practice, which were obtained from a project in cooperation with the University CTU in Prague and company Hochtief CZ a.s. Extensive experiments were carried out in the project, where the ideal concrete with admixtures was sought. Prefabricated part made of concrete composite with minimized cement content was realized, which replaced binder based on the use of secondary materials that apply modified energy by-products. It is a hydraulic ternary binder, which replaces cement in the amount of 50% compared to the original production formulation of concrete. The prefabricated part uses recycled materials or secondary raw materials of the by-product type in combination with the reduction of energy intensity, which is primarily associated with the production of cement. The implementation of the operational test of the production of the basic slab element for the prefabricated part was carried out at the concrete plant of the company Chynovska 714, 391 11 Plana nad Luznici of the company Hochtief CZ a.s., on 2 October 2019 with the possibility of further use for soundproof walls waste rubber in a thickness of 20 mm, with resistance to aggressive environments and service life of 30 years. The new implementation has a positive impact on the environment while achieving a lower carbon footprint and at the same time the use of part of materials that otherwise end up as waste, the implementation leads to CO2 reduction and actively supports the Waste Management Plan of the Czech Republic (WMP) for the period 2015-2024.
Paper deals with the assessment of practical utilization of granulated cable plastic waste (GCPW)... more Paper deals with the assessment of practical utilization of granulated cable plastic waste (GCPW) for the production of stabilized soil layers in transport engineering. The main goal of the experimental work was the evaluation of the influence of GCPW on mechanical properties of soil stabilization based on the fluidized fly ash. Mechanical properties were investigated using standard procedures in soil mechanics. GCPW was dosed as a partial replacement of fluidized fly ash up to 30 %. It was concluded, that the studied level of replacement performs critical level, additional increasing of GCPW would lead to a decline of required mechanical properties. Besides, replacement by studied waste material caused lower values of the bulk density.
SPECIAL CONCRETE AND COMPOSITES 2020: 17th International Conference, 2021
The objective of the research is to investigate the mechanical properties of the newly designed l... more The objective of the research is to investigate the mechanical properties of the newly designed lightweight cement-based refractory composite before and after high-thermal loading. To produce convenient refractory material was chosen binder system based on aluminous cement. Lightweight composite/concrete (LWC) is an effective and easy way to deduce a dead load of the structure. Besides, LWC is mainly formed by porous materials and high content of air bubbles. That's the reason why its coefficients of heat conduction and linear expansion is smaller than that of ordinary concrete. Therefore, LWC provides better thermal conservation, high-temperature resistance, and fire endurance. The designed composite in this paper content a lightweight aggregate Liaver in combination with chopped basalt fibers and air-entraining additive to secure the necessary values of bulk density, and was therefore classified as a lightweight composite. The short fibers are also applied for the purpose to support the composite resistance to inner tension caused by high thermal loading and achieve better residual properties.
The article is aimed at the description of design, 3D modelling and simulation of technology for ... more The article is aimed at the description of design, 3D modelling and simulation of technology for processing and fabrication of the formwork for complex concrete structures. The process of fabrication of complex-shaped elements from the special composite concrete mixture with application of several sophisticated software, technologies and industrial robot KUKA Agilus is also described in this work. The RHWC (Robotic Hot Wire Cutter) technology fully matches the prior aspects of the Industry 4.0 concept. The study consists of four parts. The first part simplified describes the mathematical apparatus of parametric modelling for complex concrete surfaces in Rhino 6.0 software. During the research two figures was precisely designed and modelled. The second part is aimed at the description of contemporary architectural trends in complex concrete structures manufacturing, modelling and analysis of ability to implement the complex-shaped surfaces with the RHWC technology. The third part des...
Proceedings of the 4th Brazilian Conference on Composite Materials, 2018
This article is focusing on comparison of plasticizing and air-entraining additives and their eff... more This article is focusing on comparison of plasticizing and air-entraining additives and their effect on mechanical properties of composite based on aluminous cement. Achieved results supposed to help during the development of lightweight composite able to withstand temperatures over 1000 °C and reduce heat transfer from a high temperature source, either by direct contact (conduction/convection) or via radiation. Operation at high temperature is of fundamental importance to many major sectors of industry, including material production and processing, chemical engineering, power generation and more. Objective is to achieve competitive performance with competitive life cycle costs. Maximum material efficiency and minimum manufacturing and operating costs are key factors in meeting this objective. Selection of a materials with sufficient economic conditions for a particular application must take account of many factors. For the purpose of this experiment, specimens were created from cement paste and different dosage of chopped carbon fibres. Experimental investigation underwent two series of samples different in the type of used additives. First series contains plasticizing additive, second series contains air-entraining additive. The purpose was to determine the different effect on the workability of fresh mixture, bulk density and mechanical properties. The strength of samples was measured after exposure to high temperatures of 600 °C and 1000 °C. The residual properties were compared between each other and also to samples dried at the temperature of 105 °C. Obtained results revealed the level of influence of mentioned additives on the composition of studied refractory composite.
The paper presents the impact of doses of an air-entraining additive on the mechanical properties... more 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...
The results of an experimental investigation of the influence of chopped alumina-silica bulk fibe... more The results of an experimental investigation of the influence of chopped alumina-silica bulk fibers on residual mechanical properties of lightweight cement-based composites for high temperature application are obtained. The matrix of studied specimens is based on aluminous cement, because of its sufficient temperature resistance over 1000 °C. Thermal ceramic bulk fiber offer a maximum temperature range of between 1200° to 1500 °C. They also provide excellent chemical stability and resistance to chemical attack. If wet by oil or water, thermal and physical properties will be fully restored after drying. The benefits of using ceramic bulk fibers were evaluated by the results of physical and mechanical testing; compressive strength, flexural strength and bulk density were determined on the different levels of temperature loading. The prismatic specimens, having dimensions of 40×40×160 mm3, are cured 28 days in humid environment and after that time dried and subjected to temperatures of...
The aim of our study was to develop a composite material for industrial use that is resistant to ... more 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 dens...
Cement is an extremely energy consuming material and its production leads to the emission of a va... more Cement is an extremely energy consuming material and its production leads to the emission of a vast amount of greenhouse gases. Cementitious concrete is a universal building material, which is used for the production of various structural elements. The paper describes the problem of cement production and its impact on the environment. This research deals with application of aluminous cement as binder component for the manufacture of refractory composites and with possibilities of further utilization of environmentally friendly materials with pozzolanic properties as a partial replacement of used aluminous cement. These materials are originating as waste in the building industry or by the recycling of cast-off materials. To reduce the costs and adverse effects on the environment was the binder system modified by finely ground ceramic powder and metakaolin. The experimental results present the values of flexural and compressive strength investigated on a series of composite specimens with dimensions of 40×40×160 mm3 and 10, 20 and 30 % of cement replacement. The aim of the present work is to apply the mentioned pozzolanic materials and reach the suitable composite with the sufficient heat resistance and residual mechanical parameters after gradual temperature loading.
Development of new composite materials is the worldwide extremely progressive branch of engineeri... more Development of new composite materials is the worldwide extremely progressive branch of engineering activity. Composite materials are applied in many industries. The principle of composite materials is a combination of different materials providing an entirely new material with specific properties. Fiber-reinforced composites rank to the most frequently used composites because of their suitable mechanical properties. There were studied mechanical properties of fibre reinforced cementitious composites (FRCC) exposed to high temperatures of 600 °C and 1000 °C in the paper. For the production of refractory FRCC were used aluminous cement Secar®71 with 70 % of Al2O3. Various composites differed in the used type of fibers - basalt, carbon and ceramic fibres were applied in doses of 2 % by volume. For the experimental program were prepared prismatic specimens with the total dimensions of 40 × 40 × 160 mm3 and cured for 28 days in humid environment. Residual bulk density, flexural and comp...
The main aim of this contribution lies in the description of mechanical properties fiber cement c... more The main aim of this contribution lies in the description of mechanical properties fiber cement composites after exposure to high temperatures. Destructive and non-destructive methods were used to investigate the influence of heat loading. The effect of refractory binder compared to common Portland cement binder was observed. Widespread non-destructive testing method can describe the changes of mechanical properties due to influence of external load e.g. high temperature at the level of 1000 °C. The tensile strength and compressive strength were investigated on specimens 40 x 40 x 160 mm. Before these destructive tests dynamic modulus of elasticity and tentative compressive strength were provided.
This paper summarizes the results of an experimental program aimed at investigating of the mechan... more 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...
This paper describes the application of lightweight aggregate (LWA) in the creation of fire resis... more This paper describes the application of lightweight aggregate (LWA) in the creation of fire resistant composite. The effort of the project is the preparation of a light refractory material with good mechanical properties, which would reach technically economical solutions. We initially chose as lightweight aggregate Liaver, which in combination with chamotte aggregate represent the filler of composite. The following observations were focused on partial replacement of binding components with brick dust and its influence on the mechanical properties of the composite. After design process, test composite specimens were produced to determine hardened properties at standard age. On the 28 day were all the mixtures exposed to 105, 600 and 1000 °C. Lastly, the flexural and compressive strength tests were performed on the composite specimens to identify high temperature effect comparing to strength test results obtained from standard laboratory conditions.
Following article deals with experimental investigation of elevated temperatures influence on mec... more Following article deals with experimental investigation of elevated temperatures influence on mechanical properties of refractory cement composite, which seems to be very progressive and interesting field of material science. Specimens 40 x 40 x 160 mm3 were exposed to 600 °C and 1000 °C for three hours. Using of aluminous cement, in this case Secar®71 with70 % of Al2O3, means the basic premise for refractory composites. Natural crushed basalt aggregate of two fractions 0-4 mm and 2-5 mm works as filler. Metakaolin MefistoL05 in amount 225 kg/m3 represents the fine filler, commonly used in refractory concrete production. Ceramic fibers or combination of two lengths of basalt fibers significantly improve the flexural characteristics. The goal of this research is to quantified influence of basalt fibers and ceramic fibers on flexural strength, compressive strength and bulk density of cement composite in high temperature conditions.
Present paper deals with experimental study of refractories manufactured with environmentally fri... more 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.
Computational Methods and Experimental Measurements XVII, 2015
This paper deals with the experimental study of the composition of special highperformance Portla... more This paper deals with the experimental study of the composition of special highperformance Portland cement based composites and their resistance to de-icing salt scaling. The aim of this was to evaluate the impact of pozzolanic additiveburnt clay, the application of which is documented by several research works. Studied composites are formulated as fine-grain high performance concrete with high dose of Portland cement and silica fume and very low rate of water-cement ratio to ensure reduced permeability. Burnt clay was applied as cementitious supplementary material to reduce the environmental impact of concrete mixtures and to obtain suitable microstructure. Portland cement replacement by the above mentioned additive was gradually elevated just up to the rate of 60% of Portland cement weight. Investigation of scaling resistance was complemented by measuring surface water absorption and determination of flexural and compressive strength which exceeded the level of 100 MPa for studied mixtures. Mechanical properties were not extensively affected by burnt clay additive, but the essential impact of studied pozzolanic material was noticeable in the case of scaling and absorption tests, which means processes regulated by permeability. In this point of view, optimum rate of replacement by burnt clay seems to be about 30% of Portland cement weight. A mixture with optimal composition exhibited increased durability by more than 50% to reference mixture. Application of burnt clay contributed to good potential for practical use for all tested properties with significant production energy savings.
Significant advances in the field of building materials leads to increasingly frequent enforcemen... more 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.
Fundamental tasks of material engineers are the application of materials, which can be manufactur... more Fundamental tasks of material engineers are the application of materials, which can be manufactured from the less valuable materials with conservation or increasing of final properties, predominantly higher strength and durability. Present paper contributes to the category of experimental research of special composites development. Article describes the application of secondary raw materials for the production of special fibre-reinforced composite for high temperature application. These secondary raw materials are arising by the recycling of waste produced in the building industry or by the recycling of cast-off materials. Aim of performed experimental program was to prepare lightweight refractory materials based on aluminous cement with sufficient mechanical properties. Application of secondary raw materials could be interesting solution with environmental benefits. Investigation of new type of fire resistant composites were realized on the base mechanical properties determination ...
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