Effects of Inclination Angle on Pullout Performance of Hooked End Fiber Embedded in UHPC

2019 ◽  
Vol 812 ◽  
pp. 60-65
Author(s):  
Y.Y.Y. Cao ◽  
Q.L. Yu ◽  
H.J.H. Brouwers
Keyword(s):  
Mechanical Strength ◽  
Inclination Angle ◽  
High Performance ◽  
High Performance Concrete ◽  
Absorption Capacity ◽  
Fiber Reinforced Concrete ◽  
Ultra High Performance Concrete ◽  
Energy Absorption Capacity ◽  
High Performance Fiber ◽  
Inclination Angles

Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) is a material with superior mechanical strength and energy absorption capacity. The orientation of the fiber and the fiber-matrix bond relationship are important factors that affect the performance of UHPFRC. In this study, the pullout performances of hooked end fibers embedded in ultra-high performance concrete (UHPC) matrix under various inclination angles are investigated. It is shown that for the tested fiber and UHPC matrix, the optimum angle for reaching the maximum pullout energy is around 10 degrees; when the inclination angle further increases fiber rupture and matrix spalling occur more frequently. Results from this study can contribute to a better understanding and utilization of fibers effects in UHPFRC.

Influence of Hybrid Steel Fiber Addition on Direct Tensile Behavior of UHPC

2016 ◽  
Vol 713 ◽  
pp. 270-272
Author(s):  
Seung Hun Park ◽  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Gi Hong An ◽  
Nam Kon Lee
Keyword(s):  
High Performance ◽  
Steel Fiber ◽  
Absorption Capacity ◽  
Tensile Behavior ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Energy Absorption Capacity ◽  
High Performance Fiber ◽  
Direct Tensile ◽  
Direct Tensile Test

This paper examines the direct tensile behavior of ultra high performance fiber reinforced concrete (UHPFRC) according to the addition of hybrid-type steel fibers with different lengths and diameters but identical aspect ratio. Two types of steel fibers that are MS fiber with length of 20 mm and diameter of 0.2 mm and LS fiber with length of 22 mm and diameter of 0.22 mm are adopted and admixed together with different proportions to give three series of mixes (MS10LS05, MS075LS075, MS05LS10). Direct tensile test is conducted on specimens using each of the considered mixes and notched on both sides. The results show that the tensile strength and the energy absorption capacity of UHPFRC tend to increase with larger proportions of relatively long steel fibers.

Effect of Density on Compressive Strength of Ultra High Performance Fiber Reinforced Concrete (UHPFRC) Using Design of Experiment

2016 ◽  
Vol 249 ◽  
pp. 119-124 ◽  
Author(s):  
Mohammad Ali Mosaberpanah ◽  
Ozgur Eren
Keyword(s):  
Compressive Strength ◽  
Silica Fume ◽  
Design Of Experiment ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Ultra High Performance Concrete ◽  
Curing Conditions ◽  
High Performance Fiber

This paper aims to model the effect of density in 7, 14, 28 days on compressive strength of Ultra High Performance Concrete (UHPC) in same compaction and curing conditions by Design of Experiments (DOE) methodology using vary range of 5 variables: Silica fume (SF), Steel Fiber, Cement 42.5, Superplasticizer (SP), and water cemetiotious ratio (w/c).The results shows the significance effect of density on compressive strength of UHPC in different days, The models are valid for the mixes made with 1.0 sand, 0.15-0.30 silica fume amount, 0.70-1.30 cement amount, 0.10- 0.20 steel fiber, 0.04- 0.08 superplasticizer (all values are by sand by weight mass) and 0.18- 0.32 water cementitious ratio.

Contact Modeling of the Duct-Concrete Interface in the Evaluation of Multistrand Effect in High Curvature Post-Tensioned Tanks

2016 ◽  
Vol 681 ◽  
pp. 197-213
Author(s):  
Fernando Medina-Reguera ◽  
Héctor Cifuentes-Bulté ◽  
Fernando Medina-Encina
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Small Radius ◽  
Ultra High Performance Concrete ◽  
Inner Pressure ◽  
Pile Up ◽  
High Performance Fiber ◽  
Post Tensioning ◽  
Post Tensioned

Post-tensioned tanks for nuclear and energy storage applications are small radius cylindrical concrete structures in most cases. A large pre-compression force must be applied to withstand the high levels of tension produced by both the inner pressure and the temperature gradient between the inner and outer faces of the wall (regardless of the inhomogeneous material alteration due to the latter). Hence, high curvature horizontal (circumferential) tendons with a large number of strands, heavily post-tensioned, must be placed with the smallest possible vertical separation. The resultant radial post-tensioning force is transmitted to the net concrete section through its interface with the duct. The strands however pile up pushing inside the duct producing vertical pressure components along an arc, as well as the flattening out of the duct. The duct detaches then of the concrete leading to a crack initiation. This study presents a strongly non-linear model that attempts to account for all these factors. The results show that the concrete-duct contact must be modeled in order to prevent a crack sewing effect that may greatly overestimate the section capacity to withstand the post-tensioning, not to say the service mechanical and thermal loads. It also shows that these structures require higher tensile concrete strengths, and Ultra High Performance Concrete and Ultra High Performance Fiber Reinforced Concrete must be considered in order to make these tanks viable.

scholarly journals Resistance of an Optimized Ultra-High Performance Fiber Reinforced Concrete to Projectile Impact

Buildings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 63
Author(s):  
Anna L. Mina ◽  
Michael F. Petrou ◽  
Konstantinos G. Trezos
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Fiber Reinforced ◽  
Depth Of Penetration ◽  
Projectile Impact ◽  
High Performance Fiber

The scope of this paper is to investigate the performance of ultra-high performance fiber reinforced concrete (UHPFRC) concrete slabs, under projectile impact. Mixture performance under impact loading was examined using bullets with 7.62 mm diameter and initial velocity 800 m/s. The UHPFRC, used in this study, consists of a combination of steel fibers of two lengths: 6 mm and 13 mm with the same diameter of 0.16 mm. Six composition mixtures were tested, four UHPFRC, one ultra-high performance concrete (UHPC), without steel fibers, and high strength concrete (HSC). Slabs with thicknesses of 15, 30, 50, and 70 mm were produced and subjected to real shotgun fire in the field. Penetration depth, material volume loss, and crater diameter were measured and analyzed. The test results show that the mixture with a combination of 3% 6 mm and 3% of 13 mm length of steel fibers exhibited the best resistance to projectile impact and only the slabs with 15 mm thickness had perforation. Empirical models that predict the depth of penetration were compared with the experimental results. This material can be used as an overlay to buildings or to construct small precast structures.

scholarly journals Influence of Cracking on Oxygen Transport in UHPFRC Using Stainless Steel Sensors

2019 ◽  
Vol 10 (1) ◽  
pp. 239
Author(s):  
Ana Martínez-Ibernón ◽  
Marta Roig-Flores ◽  
Josep Lliso-Ferrando ◽  
Eduardo J. Mezquida-Alcaraz ◽  
Manuel Valcuende ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Oxygen Availability ◽  
Fiber Reinforced Concrete ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced ◽  
Ultra High Performance Concrete ◽  
Cracking Behavior

Reinforced concrete elements frequently suffer small cracks that are not relevant from the mechanical point of view, but they can be an entrance point for aggressive agents, such as oxygen, which could initiate the degradation processes. Fiber-Reinforced Concrete and especially Ultra High Performance Concrete increase the multi-cracking behavior, reducing the crack width and spacing. In this work, the oxygen availability of three types of concrete was compared at similar strain levels to evaluate the benefit of multi-cracking in the transport of oxygen. The types of concrete studied include traditional, High-Performance, and Ultra-High-Performance Fiber-Reinforced Concrete with and without nanofibers. To this purpose, reinforced concrete beams sized 150 × 100 × 750 mm3 were prepared with embedded stainless steel sensors that were located at three heights, which have also been validated through this work. These beams were pre-cracked in bending up to fixed strain levels. The results indicate that the sensors used were able to detect oxygen availability due to the presence of cracks and the detected differences between the studied concretes. Ultra High Performance Concrete in the cracked state displayed lower oxygen availability than the uncracked High Performance Concrete, demonstrating its potential higher durability, even when working in cracked state, thanks to the increased multi-cracking response.

Development and Mix Design of HPC and UHPFRC

2014 ◽  
Vol 982 ◽  
pp. 130-135 ◽  
Author(s):  
Pavel Reiterman ◽  
Marcel Jogl ◽  
Vit Baumelt ◽  
Jaroslav Seifrt
Keyword(s):  
Cross Sections ◽  
High Performance ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Mix Design ◽  
Internal Space ◽  
Concrete Mix Design ◽  
High Performance Fiber ◽  
Modern Solution

Application of HPC (High performance concrete) is very popular and modern solution in current architecture. Higher mechanical and durability properties allow using of thin-walled cross-sections bringing savings of materials and internal space of buildings. This paper deals with development of HPC and UHPFRC (Ultra high performance fiber reinforced concrete) mix design and impact of composition to final mechanical properties. Mix design is focused first on the influence of various additives such as fly ash, silica fume and quartz flour and then to different dosage of steel fibers.

scholarly journals Ultra high Performance Concrete - Materials Formulations and Serviceability based Design

2018 ◽  
Author(s):  
Barzin Mobasher ◽  
Yiming Yao ◽  
Aashay Arora ◽  
Narayanan Neithalath
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Analytical Models ◽  
Tension Stress ◽  
Optimization Approach ◽  
Cement Composites ◽  
Ultra High Performance Concrete

Materials and mechanical design procedures for ultra-high performance cement composites (UHPC) members based on analytical models are addressed. A procedure for the design of blended components of UHPC is proposed using quaternary cementitious materials. The blending procedures are used using a packing and rheology optimization approach to blend high performance mixtures using non-proprietary formulations. Closed-form solutions of moment-curvature responses of UHPC are derived based on elastic-plastic compressive model and trilinear strain hardening tension stress strain responses. Tension stiffening behavior of UHPC due to fiber toughening and distributed cracking is then incorporated in the cross-sectional analysis. Load-deflection responses for beam members are obtained using moment-area, and direct integration approach. The proposed models provide insights in the design of SHCC to utilize the hardening properties after cracking. Using proper parameters, generalized materials model developed are applicable to both SHCC and strain softening cement composites such as steel fiber reinforced concrete (SFRC), textile reinforced concrete (TRC) and ultra-high performance concrete (UHPC).DOI: http://dx.doi.org/10.4995/HAC2018.2018.8263

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