scholarly journals Strain rate effects on ultra high performance fiber reinforced concrete (UHP-FRC) with various fiber contents

Author(s):  
Sayed-Mohammad Banitabaei-Koupaei

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) was introduced in the mid-1990s and has made striking advances in recent years. Ductal® is a UHP-FRC technology that offers a unique combination of characteristics including but, not limited to ductility, strength and durability, while providing highly moldable products with quality surfaces. Compressive strengths, and equivalent flexural strengths reach up to 200 and 40 MPa, respectively. UHP-FRC also shows an outstanding performance under dynamic loading in structures subjected to extreme loading conditions such as impact, earthquake and blast. Moreover, UHP-FRC indicates an optimized combination of properties for a specific application. Three series of tests including compression, indirect tension, and flexure were conducted under various strain rates from quasi-static to dynamic loading with low strain rates. The objective of this project is to enhance knowledge of strain rate effects on UHP-FRC with various fiber contents and to report Dynamic Increase Factor (DIF).

2021 ◽  
Author(s):  
Sayed-Mohammad Banitabaei-Koupaei

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) was introduced in the mid-1990s and has made striking advances in recent years. Ductal® is a UHP-FRC technology that offers a unique combination of characteristics including but, not limited to ductility, strength and durability, while providing highly moldable products with quality surfaces. Compressive strengths, and equivalent flexural strengths reach up to 200 and 40 MPa, respectively. UHP-FRC also shows an outstanding performance under dynamic loading in structures subjected to extreme loading conditions such as impact, earthquake and blast. Moreover, UHP-FRC indicates an optimized combination of properties for a specific application. Three series of tests including compression, indirect tension, and flexure were conducted under various strain rates from quasi-static to dynamic loading with low strain rates. The objective of this project is to enhance knowledge of strain rate effects on UHP-FRC with various fiber contents and to report Dynamic Increase Factor (DIF).


2021 ◽  
Author(s):  
Aria Aghajani-Namin

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) is relatively new cementitious material, which has been developed to enhance material performance such as, durability, workability and strength. UHP-FRC has an outstanding dynamic performance with high capacity to absorb damage. Because of its superior performance under dynamic loading, UHP-FRC has been induced in structures where dynamic resistance is required. It is proven that like other concrete materials, UHP-FRC strength increases significantly when subjected to high strain rates. The objective of this study is to develop understanding of strain rate sensitivity of UHP-FRC with 2% steel fiber by volume fraction and plain High Strength Concrete (HSC). Compressive and flexural tensile strength of each concrete composite were investigated to evaluate and compare their strain rate sensitivity through dynamic increase factor (DIF). The specimens were tested under six different strain rates; three in quasi-static and three in dynamic domain. Strain rates in quasi-static domain conducted by MTS test machine and strain rates in dynamic domain conducted using the drop hammer technique. The test results revealed that UHP-FRC exhibits less strain rate sensitivity while HSC show much higher rate sensitivity in comparison to other materials.


2021 ◽  
Author(s):  
Aria Aghajani-Namin

Ultra High Performance Fiber Reinforced Concrete (UHP-FRC) is relatively new cementitious material, which has been developed to enhance material performance such as, durability, workability and strength. UHP-FRC has an outstanding dynamic performance with high capacity to absorb damage. Because of its superior performance under dynamic loading, UHP-FRC has been induced in structures where dynamic resistance is required. It is proven that like other concrete materials, UHP-FRC strength increases significantly when subjected to high strain rates. The objective of this study is to develop understanding of strain rate sensitivity of UHP-FRC with 2% steel fiber by volume fraction and plain High Strength Concrete (HSC). Compressive and flexural tensile strength of each concrete composite were investigated to evaluate and compare their strain rate sensitivity through dynamic increase factor (DIF). The specimens were tested under six different strain rates; three in quasi-static and three in dynamic domain. Strain rates in quasi-static domain conducted by MTS test machine and strain rates in dynamic domain conducted using the drop hammer technique. The test results revealed that UHP-FRC exhibits less strain rate sensitivity while HSC show much higher rate sensitivity in comparison to other materials.


1985 ◽  
Vol 64 ◽  
Author(s):  
George G. Nammur ◽  
Antoine E. Naaman

ABSTRACTHigh strain rates lead to substantial modifications in the stress-strain (or stress-displacement) response of fiber reinforced concrete in tension. These modifications include higher strength and corresponding strain, as well as smaller displacement at failure.The purpose of this paper is to investigate the behavior of fiber reinforced concrete under impact tensile loading, and to study the effect of strain rate on the post-cracking strength of the composite. The variation of the tensile strength of the matrix with the reinforcement parameters such as volume fraction Vf and aspect ratio |/φ of the fibers is also studied ip this paper. A special emphasis is placed on the stress-displacement relationship of steel fiber reinforced concrete in its post-cracking range. An empirical model of the stress- displacement relationship as a function of the strain rate is developed from experimental data from tensile tests on dogbone shape notched tensile prisms. The model highlights the effects of strain rate and fiber properties on the post-cracking strength of the composite, as well as the displacement at failure. The effect of strain rate on the post-cracking toughness of fiber reinforced concrete is also addressed. The literature on impact effects on concrete in tension (plain and fiber reinforced) is briefly reviewed in this paper, and so is the state of the art of testing techniques for strain rate effects.


2016 ◽  
Vol 79 ◽  
pp. 169-184 ◽  
Author(s):  
Ngoc Thanh Tran ◽  
Tuan Kiet Tran ◽  
Joong Kyu Jeon ◽  
Jun Kil Park ◽  
Dong Joo Kim

2021 ◽  
Vol 63 (3) ◽  
pp. 40-45
Author(s):  
Tri Thuong Ngo ◽  
◽  
Van Hai Hoang ◽  

In this study, the flexural resistance of ultra-high-performance fiber-reinforced concrete (UHPFRCs) containing different fiber volume content, under static and dynamic flexural loading was investigated. Thirty-six specimens of UHPFRCs, size 0.5x0.5x210 (mm), reinforced with 0.5%, and 1.5% volume of smooth steel fiber (d=0.2 mm, l=19 mm) were cast and tested by three-point bending test, under the static load (strain rate 1.67x10-5 s-1) and high acceleration load (strain rate up to 210 s-1). Experimental results show that the flexural strength of UHPFRCs increases significantly when the fiber reinforcement content increases. In addition, as the loading speed increases, the flexural resistance of the material also increases. The flexural strength of UHPFRC material reinforced with 0.5 and 1.5% of fiber volume content was 17.7 and 30.0 MPa at static loads, increased to 23.6 and 51.92 MPa at a loading rates of 110 s-1 and 28.86 and 61.04 MPa at loading rate of 210 s-1.


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