Tension softening diagram of steel fiber reinforced concrete and size effect on the flexural strength

2011 ◽  
Vol 71-78 ◽  
pp. 1083-1089
Author(s):  
Zhang Luo

Extensive experimental research has been done on rate-dependent properties normal concrete, but very little on the tensile properties of steel fiber reinforced concrete (SFRC). In this article, based on a high-speed Instron servo-controlled hydraulic materials test machine is adopted to investigate the strain rate-dependent properties of bending tensile properties for SFRC. The scheme of experiment, the works of specimens fabricating and the processes of both loading and measuring were introduced. A total of 30 beam specimens are tested. The steel fiber content is varied: 0%, 1.0%, 2.0%, 3.0% and 4.0% by volume. The experimental results were analyzed. The emphasis is put on the study of the flexural strength changes of SFRC under different strain rates. It is discovered that, with the improvement of the strain rate, increasing strength of SFRC is very obvious. While the strain rate increases from 1.4×10-4s-1 to 0.53×10-4s-1, the flexural strength increasing around 30%.


Materials ◽  
2020 ◽  
Vol 13 (22) ◽  
pp. 5202
Author(s):  
Mohammad Iqbal Khan ◽  
Wasim Abbass ◽  
Mohammad Alrubaidi ◽  
Fahad K. Alqahtani

High-strength concrete is used to provide quality control for concrete structures, yet it has the drawback of brittleness. The inclusion of fibers improves the ductility of concrete but negatively affects the fresh properties of fiber-reinforced concrete. The effects of different fine to coarse aggregate ratios on the fresh and hardened properties of steel fiber reinforced concrete were investigated in this study. Mixtures were prepared with various fine to coarse aggregate (FA/CA) ratios incorporating 1% steel fiber content (by volume) at constant water to cement ratio. The workability, unit weight, and temperature of the concrete in the fresh state, and the mechanical properties of steel-fiber-reinforced concrete (SFRC) were investigated. The inclusion of fiber in concrete influenced the mobility of concrete in the fresh state by acting as a barrier to the movement of coarse aggregate. It was observed that the concrete with an FA/CA ratio above 0.8 showed better flowability in the fresh state, whilst an above 0.9 FA/CA ratio requires excessive superplasticizer to maintain the flowability of the mixtures. The compressive and flexural strength of SFRC increased with an increase in the FA/CA ratio by around 10% and 28%, respectively. Experimental values of compressive strength and flexural strength showed good agreement, however, modulus of elasticity demonstrated slightly higher values. The experimentally obtained measurements of the mechanical properties of SFRC conformed reasonably well with the available existing prediction equations, and further enabled establishing predictive isoresponse interactive equations within the scope of the investigation domain.


2018 ◽  
Vol 9 (2) ◽  
pp. 1
Author(s):  
Mustaqqim Abdul Rahim ◽  
Omi Yanti Pohan ◽  
Mohd Badrul Hisyam Ab Manaf ◽  
Ahmad Nur Aizat Ahmad ◽  
Shahiron Shahidan ◽  
...  

Steel is one of the fibers used in fiber reinforced concrete technology. Steel fibers in concrete help to improve flexural  strength and  crack  resistance. Today,  there  are  critical  shortages of  natural  resources. In  this  research,  waste concrete is being used to produce recycled aggregate. The Recycled Coarse Aggregate (RCA) is partially replaced with the natural coarse aggregate (NCA) in concrete to analyze the mechanical properties of steel fiber reinforced concrete (SFRC). Several tests were conducted, such as compression and flexural tests. Five batches (A, B, C, D and E) of concrete cube and prism samples with different proportions of RCA (0%, 25%, 50%, 75% & 100%) and 1.5% volume fraction of steel fiber were tested, together with one control sample which used 100% NCA and 0% volume fraction of steel fiber. As a result, the control sample achieved 27.32 MPa in compression strength and 0.90 MPa for flexural strength while batch A managed to achieve 48.60 MPa and 1.10  MPa respectively. The cube and prism samples of all batches (A, B, C, D, E) showed decreasing compressive and flexural strength with increasing proportion of RCA in the concrete. Four samples fully achieved more than 20 MPa of compression strength and optimum flexural strength.


2016 ◽  
Vol 857 ◽  
pp. 363-366 ◽  
Author(s):  
Mustaqqim Abdul Rahim ◽  
Zuhayr Md Ghazaly ◽  
Raja Nurazira Raja Mamat ◽  
Muhammad Azizi Azizan ◽  
Nur Fitriah Isa ◽  
...  

Slurry Infiltrated Fiber Reinforced Concrete (SIFCON) is a relatively new high performance and advanced material and can be considered as a special type of Steel Fiber Reinforced Concrete (SFRC). The hooked-end shape steel fiber assist in controlling the propagation of cracking in the matrix by improving the overall cracking resistance and by bridging across even smaller cracks. In this paper, the comparison between the steel fiber reinforcement and BRC wire mesh will obtain and also between the different thickness size. The steel fiber will use from different percentage based on volume frictions which are 0.5%, 1% and 2% with aspect ratio 67. The beam is tested for flexural strength. The relationship between loads versus deflection represented graphically. The highest flexural strength obtained in this research is 19.34 MPa with 2% volume friction of steel fiber.


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