Experimental Analysis of Hydrothermal Curing Influence on Properties of Fiber-Cement Composite

2015 ◽  
Vol 732 ◽  
pp. 55-58 ◽  
Author(s):  
Ondřej Holčapek ◽  
Pavel Reiterman ◽  
Petr Konvalinka
Keyword(s):  
Tensile Strength ◽  
High Temperature ◽  
Cement Composite ◽  
Cement Composites ◽  
Research Activity ◽  
Temperature Resistance ◽  
Hydrothermal Curing ◽  
Aluminous Cement ◽  
Curing Condition ◽  
Strength In Bending

Special industrial application of fiber-cement composites is currently one important issue of concrete industry and research activity. The field of refractory and high-temperature resistance materials is very large and contains the cement composites too. Hydrothermal curing together with using aluminous cement with refractory basalt aggregates and fibers shows high potential for its applications in high temperature. These composite is characterized by compressive strength over 140 MPa and tensile strength in bending 12 MPa (investigated on specimens 40 x 40 x 160 mm). After exposure to temperature 1000 °C these parameters are 60 MPa in compression respective 6 MPa in bending. Achieved values are significantly higher than in the case of laboratory curing condition and there are suitable especially for prefabricated fire resistance cladding or other special application in the industry.

Influence of Ceramic Fibers on Mechanical Characteristics of Refractory Composites

2014 ◽  
Vol 1054 ◽  
pp. 22-26
Author(s):  
Ondřej Holčapek ◽  
Pavel Reiterman ◽  
Petr Konvalinka
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Cement Composite ◽  
Ceramic Fibers ◽  
Explosive Spalling ◽  
Industrial Sectors ◽  
Temperature Load ◽  
Before And After ◽  
Strength In Bending

New and unexpected way of using cement composite in industrial sectors represents a current challenge for many research teams all over the world. Following contribution deals with the study of fiber-cement composite ́s mechanical properties after exposure to high temperature. This composite could be used for industry applications or for fire-resistance cladding production. Tensile strength in bending, compressive strength, bulk density and dynamic modulus of elasticity were examined on samples 40 x 40 x 160 mm. All parameters were measured before and after exposure to high temperature in electric furnace. One group contained three specimens was reference, without temperature load, the second group was exposure to 600 °C and the last one to 1000 °C. High aluminous cement Secar®71 works as refractory binder and nature crushed basalt aggregates two fractions works as filler. The composite ́s matrix was supplemented by various amounts of ceramic fibers. Especially the influence of amount of fibers on final properties was the main goal of this research. Measured mechanical parameters provide deep knowledge of their behavior after temperature on 1000 °C level. The compressive strength and tensile strength in bending achieved values 1.5 MPa. Behavior of the composite during and after temperature load was without any negative phenomena such as explosive spalling, cracks in aggregates or cement paste and macro disintegration of the composite ́s structure.

scholarly journals CYCLIC TEMPERATURE LOADING RESIDUAL FLEXURAL STRENGHT OF REFRACTORY SLABS

2017 ◽  
Vol 57 (2) ◽  
pp. 97 ◽  
Author(s):  
Ondřej Holčapek ◽  
Pavel Reiterman ◽  
Petr Konvalinka
Keyword(s):  
Tensile Strength ◽  
High Performance ◽  
Thermal Loading ◽  
Cement Composite ◽  
Composite Slabs ◽  
Cyclic Temperature ◽  
Reinforced Cement ◽  
Aluminous Cement ◽  
Strength In Bending ◽  
High Performance Fibre

This paper describes the effect of cyclic elevated temperature loading on refractory slabs made from high performance, fibre reinforced cement composite. Slabs were produced from aluminous cement-based composites, reinforced by different dosages of basalt fibres. The composite investigated in this study had self-compacting characteristics. The slabs used were exposed to different thermal loading – 600 °C, 1000 °C, six times applied 600 °C and 1000 °C. Then, flexural strength was investigated in all groups of slabs, including group reference slabs with no thermal loading. The results show that the appropriate combination of aluminous cement, natural basalt aggregate, fine filler and basalt fibres in dosage 1.00% of volume is able to successfully resist to cyclic temperature loading. Tensile strength in bending of these slabs (after cyclic temperature loading at 600 °C) achieved 6.0 MPa. It was demonstrated that it is possible to use this composite for high extensive conditions in real industrial conditions.

Mechanical and Rheological Properties of Aluminous Cement under High Temperatures

2014 ◽  
Vol 982 ◽  
pp. 141-144 ◽  
Author(s):  
Ondřej Holčapek ◽  
Pavel Reiterman ◽  
Petr Konvalinka
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Temperature ◽  
Rheological Properties ◽  
Cement Paste ◽  
Rheological Behavior ◽  
Experimental Program ◽  
Before And After ◽  
Aluminous Cement ◽  
Strength In Bending

The following article deals with the relations between rheological behavior and strength characteristics of high aluminous cement paste. There were investigated the values of flow of fresh mixture (tested with Högermann ́s table), tensile strength in bending and compressive strength at the age of 28 days on specimens 40 x 40 x 160 mm. The influence of high temperature was examined by exposure to 600 °C and 1000 °C. The results of provided experimental program confirm the fact that with increasing water-cement ration decreases compressive and tensile strength before and after temperature loading. Also was shown the effect of high temperature on refractory aluminous cement paste properites.

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.

Influence of Basalt Fibres and Aggregates on the Thermal Expansion of Cement-Based Composites

2014 ◽  
Vol 1054 ◽  
pp. 17-21 ◽  
Author(s):  
Dana Koňáková ◽  
Veronika Špedlová ◽  
Monika Čáchová ◽  
Eva Vejmelková ◽  
Robert Černý
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Open Porosity ◽  
Thermal Strain ◽  
Experimental Results ◽  
Silica Sand ◽  
Cement Composites ◽  
The Matrix ◽  
Aluminous Cement

The influence of basalt fibres and aggregates on the thermal expansion of cement composites is analyzed. Four different composite mixes based on aluminous cement are designed and tested. Experimental results show that the application of basalt components leads to the reduction of the increase of open porosity after high temperature loading from 47% to 36%, as compared with the reference mix. The matrix densities exhibit almost similar values for all studied composites; the differences are only up to 16%. The thermal strain is more than 50% lower when basalt aggregates are used instead of silica sand.

Synergistic Effect of High Temperature Fly Ash with Fluidized Bed Combustion Fly Ash in Cement Composites

2016 ◽  
Vol 722 ◽  
pp. 113-118
Author(s):  
Martin Ťažký ◽  
Rudolf Hela
Keyword(s):  
High Temperature ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Fossil Fuels ◽  
Cement Composite ◽  
Pozzolanic Reaction ◽  
Cement Composites ◽  
Fluidized Bed Combustion ◽  
Cement Pastes ◽  
Free Cao

Using high temperature fly ash for his pozzolan properties to cement composite production is known a few years ago. New ways combustion of fossil fuels also creates a new type of fly ash, named fluidized bed combustion fly ash. However, this fly ash has same pozzolan properties as has high temperature fly ash, this type is not using for production of cement composites. Fluidized bed combustion fly ash has highly variable chemical composition but usually it has a higher amount of free CaO together with sulphates. This higher amounts of free CaO after mixing of fluidized bed combustion fly ash with water to some extent becomes an activator for the beginning of the pozzolanic reaction, during which is consumed the extinguished CaO. If there is also present high temperature fly ash in cement composite, it could be accelerated his pozzolanic reaction in the same manner using a fluidized bed combustion fly ash. In this experiment was tested a synergy effect in the use of fluidized bed combustion fly ash with high temperature fly ash as an additive. The experiment was carried out on cement pastes that have been studied in particular the progress of hydration processes, pointing to a possible acceleration of pozzolanic reactions of both types of fly ash.

Behavior of Cement Composites Loaded by High Temperature

2015 ◽  
Vol 824 ◽  
pp. 121-125
Author(s):  
Veronika Špedlová ◽  
Dana Koňáková
Keyword(s):  
High Temperature ◽  
Portland Cement ◽  
High Temperatures ◽  
Experimental Program ◽  
Mechanical And Thermal Properties ◽  
Cement Composites ◽  
Basalt Fibers ◽  
Coefficient Of Thermal Conductivity ◽  
Aluminous Cement ◽  
Better Than

In this paper, there are summarized the results of an experimental program focused on basic, mechanical and thermal properties of cement composites according to the high – temperature loading. Four different materials were studied, which differed in used kind of cement and amount of fibers. As a matrix for studied composites the aluminous cement was chosen because of its resistance in high temperature. For a comparison the Portland cement was also tested. The second main ingredient used to provide better resistance in high temperatures - the basalt aggregate, was mixed in every specimen. The basalt fibers were chosen for two of the measured samples, remaining two ones were tested without fibers. The obtained data in this presented analyses show that the application of the aluminous cement leads to increase (depending on temperature) of porosity, which is the cause of decreasing of the coefficient of thermal conductivity. It can seems, that these cement composites will have low mechanical strength in high temperatures, but because of better sintering, the aluminous cement keeps its strength in high temperatures better than Portland cement.

EFFECT OF RECYCLED MATERIALS ON THE TENSILE BEHAVIOR OF STEEL FIBER-REINFORCED CEMENT COMPOSITE

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Sun-Woo Kim ◽  
Wan-Shin Park ◽  
Young-Il Jang ◽  
Yi-Hyun Nam ◽  
Sun-Woong Kim ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fly Ash ◽  
Steel Fiber ◽  
Cement Composite ◽  
Fine Aggregate ◽  
Cement Composites ◽  
Fiber Reinforced ◽  
Direct Tension ◽  
Recycled Materials ◽  
Reinforced Cement

Conventional cement composite is generally produced with ordinary Portland cement (OPC) as a binder. However, during manufacturing the cement composite, large amount of carbon dioxide (CO2) are emitted. Therefore, fly ash is proposed to be replaced to OPC in order to reduce CO2 emission of cement composites. For reinforcing fibers, micro steel fibers were used. For investigating mechanical properties of steel fiber-reinforced cement composites (SFRCCs), direct tension tests were conducted. The test results showed that fly ash improves tensile strength and ductility of SFRCCs. However, tensile strength of the SFRCC decreased as replacement ratio of recycled fine aggregate increased. The use of recycled materials in FRCC helps to save natural resources and promote sustainability in civil engineering materials.

Thermo-Mechanical Properties of Geopolymer/Carbon Fiber/TiO2 Nanoparticles (NPs) Composite

2019 ◽  
Vol 967 ◽  
pp. 267-273
Author(s):  
Subaer ◽  
Abdul Haris ◽  
Noor Afifah Kharisma ◽  
Nur Akifah ◽  
Risna Zulwiyati
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Thermal Properties ◽  
High Temperature ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Experimental Results ◽  
Temperature Resistance ◽  
Cleaning Agent ◽  
High Temperature Resistance

The main objective of this study is to investigate the thermo-mechanical properties of composite made from geopolymer/carbon fiber/TiO2 NPs. The composite was fabricated from geopolymer based on metakaolin added with carbon fibers as reinforcement and TiO2 NPs as self-cleaning agent. The thermal properties of the composite was examined by subjecting the samples to temperature up to 750OC for 4 hours. The mechanical properties of the resulting materials were measured by using flexural and tensile strength measurements. The experimental results showed that the compsite exhibited high temperature resistance and the addition of carbon fiber were increase the flexural as well as the tensile strength of the composite.

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