scholarly journals Experimental Study on the Strength Characteristics and Water Permeability of Hybrid Steel Fibre Reinforced Concrete

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
M. P. Singh ◽  
S. P. Singh ◽  
A. P. Singh

Results of an investigation conducted to study the effect of fibre hybridization on the strength characteristics such as compressive strength, split tensile strength, and water permeability of steel fibre reinforced concrete (SFRC) are presented. Steel fibres of different lengths, that is, 12.5 mm, 25 mm, and 50 mm, having constant diameter of 0.6 mm, were systematically combined in different mix proportions to obtain mono, binary, and ternary combinations at each of 0.5%, 1.0%, and 1.5% fibre volume fraction. A concrete mix containing no fibres was also cast for reference purpose. A total number of 1440 cube specimens of size 100*100*100 mm were tested, 480 each for compressive strength, split tensile strength, and water permeability at 7, 28, 90, and 120 days of curing. It has been observed from the results of this investigation that a fibre combination of 33% 12.5 mm + 33% 25 mm + 33% 50 mm long fibres can be adjudged as the most appropriate combination to be employed in hybrid steel fibre reinforced concrete (HySFRC) for optimum performance in terms of compressive strength, split tensile strength and water permeability requirements taken together.

2021 ◽  
Vol 15 (1) ◽  
pp. 81-92
Author(s):  
Constantinos B. Demakos ◽  
Constantinos C. Repapis ◽  
Dimitros P. Drivas

Aims: The aim of this paper is to investigate the influence of the volume fraction of fibres, the depth of the beam and the shear span-to-depth ratio on the shear strength of steel fibre reinforced concrete beams. Background: Concrete is a material widely used in structures, as it has high compressive strength and stiffness with low cost manufacturing. However, it presents low tensile strength and ductility. Therefore, through years various materials have been embedded inside it to improve its properties, one of which is steel fibres. Steel fibre reinforced concrete presents improved flexural, tensile, shear and torsional strength and post-cracking ductility. Objective: A better understanding of the shear performance of SFRC could lead to improved behaviour and higher safety of structures subject to high shear forces. Therefore, the influence of steel fibres on shear strength of reinforced concrete beams without transverse reinforcement is experimentally investigated. Methods: Eighteen concrete beams were constructed for this purpose and tested under monotonic four-point bending, six of which were made of plain concrete and twelve of SFRC. Two different aspect ratios of beams, steel fibres volume fractions and shear span-to-depth ratios were selected. Results: During the experimental tests, the ultimate loading, deformation at the mid-span, propagation of cracks and failure mode were detected. From the tests, it was shown that SFRC beams with high volume fractions of fibres exhibited an increased shear capacity. Conclusion: The addition of steel fibres resulted in a slight increase of the compressive strength and a significant increase in the tensile strength of concrete and shear resistance capacity of the beam. Moreover, these beams exhibit a more ductile behaviour. Empirical relations predicting the shear strength capacity of fibre reinforced concrete beams were revised and applied successfully to verify the experimental results obtained in this study.


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.


This study presents the experimental investigation carried out to study the mechanical properties of concrete with and without the addition of fibres to it.d Concrete is the most consumed material in the world which has the property of strong in compression and weak in tension. Also plain concrete possess very limited ductility and little resistance to cracking. Hence fibres are introduced in the concrete to improve the tensile strength & brittleness of the concrete. These fibres which are closely spaced and dispersed uniformly in the concrete arrest the micro and macro cracks and improve the tensile strength of concrete. Concrete admixed with such fibres are known as Fibre Reinforced Concrete. The combination of two (or) more fibres called as Hybridization is carried out in this work. M25 grade concrete is designed as per IS 10262:2009 with the volume fraction of 0-1.5%. The workability of the concrete is affected due to the addition of fibres and hence super plasticizers are added to the concrete. The fibres considered for the study are (i) Crimped Steel Fibre (0-1.5%) and (ii) Shortcut Glass Fibre (0.1-0.2%). The behaviour of the hybrid fibre reinforced concrete is investigated by conducting compressive strength test on cube specimen of size 150mmx150mmx150mm and split tensile strength test on cylinder specimen of size 150mm diameter and 300mm height. From the experimental results, the optimum fibre combinations for maximum compressive strength and spilt tensile strength of concrete are identified.


2018 ◽  
Vol 7 (3.12) ◽  
pp. 456 ◽  
Author(s):  
Ram Prasad. K ◽  
Murali. G ◽  
Parthiban Kathirve ◽  
Haridharan M K ◽  
Karthikeyan. K

This study examines compressive strength of this functionally graded steel fibre reinforced concrete (FGFRPAC). A five mixes were prepared and tested in the present study. The first series of FGFRPAC were prepared and reinforced in three layers of 3%, 1.5% and 3% with crimped, hooked end. The second series were reinforced with 2.5% steel fibre equally in all the three layers. The average amount of fibre used in FGFRPAC specimen was 2.5% which is similar to the fibre dosage used in the second series were the fibres are equally spread in all the three layers. The gathered results revealed that employing FGFRPAC leads to more enhancement in compressive strength than conventional steel fibre reinforced concrete.


2021 ◽  
Vol 350 ◽  
pp. 00008
Author(s):  
Alena Sadouskaya ◽  
Syarhei Leanovich ◽  
Neli Budrevich ◽  
Elena Polonina

There are two most popular approaches to determining the compressive strength of concrete: testing cubes, testing cylinders. The use of different samples gives different results, which are intended to characterize one parameter of the material compressive strength. The article discusses a general approach to determining the compressive strength of cylinders and cubes. The analysis of the factors influencing the transition coefficients when testing the cylinder samples with the ratio of height to diameter is less than 2. The results of testing cubes and cylinders for compression made of fiber-reinforced concrete are presented.


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