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.

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.

Reinforced Cement Composites – Effect of Hybrid Fibres on Selected Properties

2015 ◽  
Vol 824 ◽  
pp. 179-183
Author(s):  
Dana Koňáková ◽  
Eva Vejmelková
Keyword(s):  
Mechanical Properties ◽  
Thermal Loading ◽  
Bending Strength ◽  
Linear Thermal Expansion Coefficient ◽  
Linear Thermal Expansion ◽  
Cement Composite ◽  
Polypropylene Fibre ◽  
Cement Composites ◽  
Matrix Density ◽  
Reinforced Cement

In this article selected properties of a glass and polypropylene fibre reinforced cement composite materials are studied. They are determined either after preceding thermal treatment or during thermal loading. Basic physical properties (in concrete terms bulk density, matrix density and open porosity), mechanical properties (in concrete terms tensile strength and bending strength) are determined after subjecting the specimens to the pre-heating temperatures of 600°C, 800°C and 1000°C. The linear thermal expansion coefficient is measured directly as functions of temperature up to 1000°C. The critical temperature for the glass and polypropylene fibre reinforced cement composite when most properties are worsening in a significant way is found apparently 500°C.

Characteristics of Fiber Reinforced Cementitious Composites in Dependence on Casting Direction

2015 ◽  
Vol 732 ◽  
pp. 377-380 ◽  
Author(s):  
Jindřich Fornůsek ◽  
Michal Tvarog
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Cement Composite ◽  
Fiber Reinforced Concrete ◽  
The Other ◽  
Fiber Reinforced ◽  
Peak Loads ◽  
High Performance Fiber ◽  
Reinforced Cement ◽  
Specific Fracture

This paper deals about behavior of fiber reinforced cement composite in dependence on the casting direction. Almost fifty concrete prisms of size 400 x 100 x 100 mm were cast; half of these were fiber reinforced concrete (FRC) and the other half was ultra-high performance fiber reinforced concrete (UHPFRC). Approximately one half of both mixtures was cast in horizontal direction and the other half vertically. It was found that the specific fracture energy of horizontally cast prisms was approximately 4,5 times larger for both materials than the vertically cast ones. Ultimate loads of FRC were very similar for both casting directions. Peak loads of the horizontally cast UHPFRC prisms were approximately 3 times larger than the vertically cast ones. This research confirmed that there is significant influence of the casting direction on the fiber reinforced concrete characteristics.

scholarly journals Performance of ultra-high performance fibre reinforced concrete plates under impact loads

2021 ◽  
Author(s):  
Hesham Othman
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Fracture Energy ◽  
High Performance ◽  
Steel Reinforcement ◽  
Fibre Content ◽  
Fibre Reinforced Concrete ◽  
Concrete Plates ◽  
High Performance Fibre

The next generation of concrete, Ultra-High Performance Fibre Reinforced Concrete (UHP-FRC), exhibits exceptional mechanical characteristics. UHP-FRC has a compressive strength exceeding 150 MPa, tensile strength in the range of 8-12 MPa, and fracture energy of several orders of magnitudes of traditional concrete. The focus of this research is to investigate and analyze the advantage of using UHP - FRC in impact resistance structures. To achieve these goals, two experimental testing programs and major numerical investigations have been conducted. The material experimental investigation has been conducted to determine the effects of strain rate on UHP - FRC. Two parameters are investigated, namely: compressive strength (80, 110, 130, and 150 MPa); and steel fibre content (0, 1, 2, and 3%). Experimental results showed that the rate sensitivity decreases with the increase in the compressive strength ; and the dynamic enhancement of tensile strength is inversely proportional to the fibre content. The structural impact testing program focuses on the dynamic response of full - scale reinforced concrete plates as well as generating precise impact measurements. Twelve reinforced plates with identical dimensions are tested under high-mass low-velocity multi-impacts. The investigated parameters include: concrete type (NSC, HSC, and UHP - FRC), fibre volume content, and steel reinforcement ratio. The results showed that the use of UHP -FRC instead of NSC or HSC is able to change the failure mode from punching to pure flexural; and UHP -FRC containing 3% fibre has superior dynamic properties. For plates with identical steel reinforcement, the total impact energy of UHP-FRC plate containing 3% fibres is double the capacity of UHP - FRC plate containing 2% fibres , and 18 times the capacity of NSC plate. A three-dimensional finite element analysis has been performed using ABAQUS/Explicit to model multi-impacts on RC plates and the applicability is verified using existing experimental data. Concrete damage plasticity (CDP) model is adapted to define UHP - FRC. The CDP constitutive model parameters for the new material are calibrated through a series of parametric studies. Computed responses are sensitive to CDP parameters related to the tension, fracture energy, and expansion properties. The analytical results showed that the existing CDP model can predict the response and crack pattern of UHP - FRC reasonably well.

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.

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