scholarly journals TO TESTING OF STEEL FIBRE REINFORCED CONCRETE AT ELEVATED TEMPERATURE

Author(s):  
Vadims Goremikins ◽  
Lukas Blesak ◽  
Josef Novak ◽  
Frantisek Wald

Addition of steel fibres improves properties of concrete. The lack of information considering tensile and post cracking behaviour of SFRC at elevated temperatures is an obstacle on the wide use of this composite material. This work presents an experimental study of steel fibre reinforced concrete subjected to high temperature. Compressive strength, split tensile strength and ultimate bending strength were evaluated. The specimens were heated by ceramic heaters and then repacked for testing.

2016 ◽  
Vol 56 (4) ◽  
pp. 258-264 ◽  
Author(s):  
Vadims Goremikins ◽  
Lukas Blesak ◽  
Josef Novak ◽  
Frantisek Wald

<p>Generally speaking, adding a certain amount of steel fibres to a concrete mixture improves its mechanical properties. Currently, a lack of information considering tensile and post cracking behaviour of FRC at elevated temperatures is an issue to be faced. An experimental study of steel fibre reinforced concrete, also containing polymer fibres (FRC), subjected to high temperature is presented herein. Compressive strength, split tensile strength and ultimate bending strength were evaluated. Specimens were heated by the use of ceramic heaters and repacked for testing consequently. A finite-element based model was developed to predict the temperature distribution inside a specimen during both the heating and the cooling process.</p>


2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
AMIR SYAFIQ SAMSUDIN ◽  
MOHD HISBANY MOHD HASHIM ◽  
SITI HAWA HAMZAH ◽  
AFIDAH ABU BAKAR

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.


2017 ◽  
Vol 8 (3) ◽  
pp. 287-299 ◽  
Author(s):  
Vadims Goremikins ◽  
Lukas Blesak ◽  
Josef Novak ◽  
Frantisek Wald

Purpose This work aims to present an experimental study of steel fibre-reinforced concrete (SFRC) subjected to high temperature, especially focusing on residual behaviour. Design/methodology/approach Compressive strength and split tensile strength of SFRC cubes and ultimate bending strength of prisms were evaluated under ambient and elevated temperatures. The specimens were heated by ceramic heaters and then repacked for testing. Findings The results showed that a compressive strength of SFRC is reduced by 38 and 66 per cent, tensile strength is reduced by 25 and 59 per cent and ultimate bending force is reduced by 33 and 56 per cent in case of 400°C and 600°C, respectively, comparing with ambient temperature. Originality value The developed testing procedure could be used for determination of material properties of SFRC under elevated temperatures.


1996 ◽  
Vol 23 (2) ◽  
pp. 511-517 ◽  
Author(s):  
T. T. Lie ◽  
V. K. R. Kodur

For use in fire resistance calculations, the relevant thermal and mechanical properties of steel-fibre-reinforced concrete at elevated temperatures were determined. These properties included the thermal conductivity, specific heat, thermal expansion, and mass loss, as well as the strength and deformation properties of steel-fibre-reinforced siliceous and carbonate aggregate concretes. The thermal properties are presented in equations that express the values of these properties as a function of temperature in the temperature range between 0 °C and 1000 °C. The mechanical properties are given in the form of stress–strain relationships for the concretes at elevated temperatures. The results indicate that the steel fibres have little influence on the thermal properties of the concretes. The influence on the mechanical properties, however, is relatively greater than the influence on the thermal properties and is expected to be beneficial to the fire resistance of structural elements constructed of fibre-reinforced concrete. Key words: steel fibre, reinforced concrete, thermal properties, mechanical properties, fire resistance.


The present investigation is carried out to study the strength and durability characteristics of steel fibre reinforced concrete, by replacing Ordinary Portland cement with Fly Ash, Ground Granulated Blast Furnace Slag (GGBS) and Metakaolin. In this study, cement is replaced by 30% and 40% with Fly Ash, GGBS and Metakaolin for M30 and M35 grades of concrete. Steel fibres @ 1% by weight of binder is used in all the mixes. Strength characteristics like compressive strength and split tensile strength are tested at 7 days and 28 days age. Additionally, durability tests such as water absorption and Sorptivity tests are conducted after 28days curing. The test results have shown that 30% replacement is optimum for strength criteria. And when metakaolin is used with fly ash, durability properties were improved and workability reduced.


Author(s):  
Fangyuan Li ◽  
Yunxuan Cui ◽  
Chengyuan Cao ◽  
Peifeng Wu

Directionally distributed steel fibre-reinforced concrete has been proposed as a novel concrete because of its high tensile strength and crack resistance in specific directions. Based on the existing studies of the effect of the fibre direction on the mechanical properties of fibre-reinforced concrete, the authors in this paper performed further studies of the mechanical properties of directionally distributed steel fibre-reinforced concrete by conducting split tensile and bending tests. The split tensile strength of the directionally distributed fibre-reinforced concrete clearly exhibited anisotropy. The split tensile strength perpendicular to the fibre direction was much higher than that parallel to the fibre direction. The split tensile strength perpendicular to the fibre direction was almost twice the tensile strength of plain concrete. The flexural performance of directionally distributed fibre-reinforced concrete in the fibre direction significantly improved compared to that of randomly distributed fibre-reinforced concrete. Specifically, the flexural strength increased by as much as 97%. Gravity resulted in a deviation in the tensile properties of concrete prepared by manually and directionally placing fibres in a layered casting process. The test results can be utilised in subsequent concrete designs. The conclusions reached in this paper provide comprehensive mechanical design parameters for the application of directionally distributed fibre-reinforced concrete.


2018 ◽  
Vol 15 (1) ◽  
pp. 15
Author(s):  
Amir Syafiq Samsudin ◽  
Mohd Hisbany Mohd Hashim ◽  
Siti Hawa Hamzah ◽  
Afidah Abu Bakar

Nowadays, demands in the application of fibre in concrete increase gradually as an engineering material. Rapid cost increment of material causes the increase in demand of new technology that provides safe, efficient and economical design for the present and future application. The introduction of ribbed slab reduces concrete materials and thus the cost, but the strength of the structure also reduces due to the reducing of material. Steel fibre reinforced concrete (SFRC) has the ability to maintain a part of its tensile strength prior to crack in order to resist more loading compared to conventional concrete. Meanwhile, the ribbed slab can help in material reduction. This research investigated on the bending strength of 2-ribbed and 3-ribbed concrete slab with steel fibre reinforcement under static loading with a span of 1500 mm and 1000 mm x 75 mm in cross section. An amount of 40 kg/m  steel fibre of all total concrete volume was used as reinforcement instead of conventional bars with concrete grade 30 N/mm2. The slab was tested under three-point bending. Load versus deflection curve was plotted to illustrate the result and to compare the deflection between control and ribbed slab. This research shows that SFRC Ribbed Slab capable to withstand the same amount of load as normal slab structure, although the concrete volume reduces up to 20%.


Author(s):  
M. F. Novikov ◽  
Yu. I. Kozyreva

One of the ways to increase the strength and reliability of building structures is the use of steel – fibre reinforced concrete. Steel – fibre reinforced concrete has significant advantages over conventional concrete. A high degree of resistance to cracking contributes to an increase in such physical and mechanical parameters as compressive, tensile and bending strength, water resistance, frost resistance, resistance to water and chemical penetration. In steel – fibre reinforced concrete, steel – fibre is used as a reinforcing material, evenly distributed over the volume of concrete.In the process of steel – fibre production, the fiber is cut with carbide knives. The article deals with the issues of increasing the wear resistance of carbide knives used for cutting steel – fibre, and suggests ways to increase the durability of cutting tools. The influence of the quality of tungsten-cobalt hard alloy on the wear resistance of knives is analyzed, and a knife attachment device is developed.


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