Steel fibre content and interconnection induced electrochemical corrosion of Ultra-High Performance Fibre Reinforced Concrete (UHPFRC)

2018 ◽  
Vol 94 ◽  
pp. 191-200 ◽  
Author(s):  
Qiulei Song ◽  
Rui Yu ◽  
Zhonghe Shui ◽  
Suduan Rao ◽  
Xinpeng Wang ◽  
...  
2021 ◽  
Author(s):  
Hesham Othman

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.


2016 ◽  
Vol 7 (4) ◽  
pp. 328-348 ◽  
Author(s):  
C. Kahanji ◽  
F. Ali ◽  
A. Nadjai

Purpose The purpose of the study was to investigate the spalling phenomenon in ultra-high performance fibre reinforced concrete (UHPFRC) beams on exposure to a standard fire curve (ISO 834) under a sustained load. Design/methodology/approach The variables in this study were steel fibre dosage, polypropylene (PP) fibres and loading levels. The research investigated seven beams – three of which contained steel fibres with 2 vol.%, another three had steel fibres with 4 vol.% dosage and the seventh beam had a combination of steel fibres (2 vol.%) and PP fibres (4 kg/m3). The beams were tested for 1 h under three loading levels (20, 40 and 60 per cent) based on the ambient temperature ultimate flexural strength of the beam. Findings Spalling was affected by the loading levels; it exacerbated under the load level of 40 per cent, whereas under the 60 per cent load level, significantly less spalling was recorded. Under similar loading conditions, the beams containing steel fibres with a dosage of 4 vol.% spalled less than the beams with fibre contents of 2 vol.%. This was attributed to the additional tensile strength provided by the excess steel fibres. The presence of PP fibres eliminated spalling completely. Originality/value There is insufficient research into the performance of UHPFRC beams at elevated temperature, as most studies have largely focussed on columns, slabs and smaller elements such as cubes and cylinders. This study provides invaluable information and insights of the influence of parameters such as steel fibre dosage, PP fibres, loading levels on the spalling behaviour and fire endurance of UHPFRC beams.


Author(s):  
A.A Ibrahim ◽  
D.O Oyejobi ◽  
A.A Adedeji

It is important to advance the technology of concrete due to incidences of structural failure, terrorist attack and natural disaster which has led to the evolution of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) as a means to develop novel materials to build structures with superb strength, high ductility and repairing structures that have experienced structural failure. Development of agro-industrial waste materials for production of UHPFRC will significantly reduce the energy consumed and the environmental impacts during concrete production. In this study, a literature review of the production, properties and usage of UHPFRC was conducted. Following the review, locally available materials that could be used to replace the important constituent materials of UHPFRC were appraised. It was gathered that UHPFRC is an excellent strengthening material with ultra-high mechanical properties for structural applications. The major components of UHPFRC are cement, silica fume, steel fibre, water, superplasticizer, and sand. Recycled steel fibre and rice husk ash (RHA) are locally available materials and have similar properties to industrial steel fibre and silica fume respectively. These local materials can be incorporated into concrete to further improve the properties of concrete, promote sustainability and discourage importation of silica fume and different types of fibres.


2021 ◽  
Author(s):  
Hesham Othman

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.


2018 ◽  
Vol 183 ◽  
pp. 02005
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni

The paper presents the results obtained on cylindrical Ultra High Performance Fibre Reinforced Concrete specimens with diameter of 30mm and a height of 60mm under compression at high stress rate (1.7–2.3 TPa/s). Four different percentages of fibre reinforcement are considered (1, 2, 3, and 4% fibre content) and compared with the results of the matrix (UHPC). A slight reduction of the strength and fracture time with the introduction of fibres is observed. The experimental results are analysed and discussed with the intent to better understand the mechanical behaviour of UHPFRC materials in case of dynamic event under service loading conditions.


2008 ◽  
Vol 17 (11) ◽  
pp. 316-317
Author(s):  
Daniel de MATTEIS ◽  
Pierre MARCHAND ◽  
Aude PETEL ◽  
Thierry THIBAUX ◽  
Nicolas FABRY ◽  
...  

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