scholarly journals Pullout Response of Ultra-High-Performance Concrete with Twisted Steel Fibers

2019 ◽  
Vol 9 (4) ◽  
pp. 658 ◽  
Author(s):  
Judong Ye ◽  
Guohua Liu
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Surface ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Theoretical Formula ◽  
Element Analysis ◽  
Pullout Force ◽  
Pull Out ◽  
Before And After

This paper aims to develop a pullout force formula and increase the understanding of the damage mechanisms of ultra-high-performance fiber reinforced concrete (UHPFRC) with twisted steel fibers (TSFs) through a pull-out test and finite element analysis (FEA). The formula was first obtained through a theoretical force analysis with model assumptions that are based on the experimental data in the literature. A microscale in-situ X-ray computed tomography (µXCT) was used to prepare 3D images of the cross-section of concrete before and after TSFs with three embedment lengths were pulled out. The tested pullout force values were used for comparison with the developed formula values. The µXCT images show the concrete matrix was preserved after the TSF was pulled out, indicating the stable pullout force values at the strain hardening stage was mainly caused by the fiber untwisting. FEA results show this untwisting behavior occurs on the effective untwisting length of TSF close to the exterior concrete surface. The theoretical formula values were found match well with the testing data. The developed formula is potentially used to analyze the pullout behavior of TSF with different geometries; thus, the design of the UHPFRC with TSFs can be optimized in the field.

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.

Repair of Severely Damaged Reinforced Concrete Beams with High-Strength Cementitious Grout

2020 ◽  
Vol 2674 (6) ◽  
pp. 372-384
Author(s):  
Antoine N. Gergess ◽  
Mahfoud Shaikh Al Shabab ◽  
Razane Massouh
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
High Performance Concrete ◽  
High Strength ◽  
Cementitious Materials ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Reinforced Concrete Beams ◽  
Rc Beams ◽  
Rc Structures

High-strength cementitious materials such as high-performance concrete are extensively used for retrofit of reinforced concrete (RC) structures. The effectiveness of these materials is increased when mixed with steel fibers. A commonly used technique for strengthening and repair of RC beams consists of applying high-performance fiber-reinforced concrete jackets around the beam perimeter. This paper investigates the jacketing method for repairing severely damaged RC beams. Four 2 m (6 ft 63/4 in.) long rectangular RC beams, 200 × 300 mm (8 ×12 in.) were initially cast and loaded until failure based on three-point bending tests. The four beams were then repaired by thickening the sides of the damaged RC beams using a commercially available high-strength shrinkage grout with and without steel fibers. Strain and deformation were recorded in the damaged and repaired beams to compare structural performance. It is shown that the flexural strength of the repaired beams is increased and the crack pattern under loading is improved, proving that the proposed repair method can restore the resistance capacity of RC beams despite the degree of damage. A method for repair is proposed and an analytical investigation is also performed to understand the structural behavior of the repaired beams based on different thickening configurations.

scholarly journals On enhancing the mechanical behavior of ultra-high performance concrete through multi-scale fiber reinforcement

2021 ◽  
Author(s):  
Ketan Ragalwar ◽  
William Heard ◽  
Brett Williams ◽  
Dhanendra Kumar ◽  
Ravi Ranade
Keyword(s):  
Mechanical Properties ◽  
High Performance ◽  
High Performance Concrete ◽  
Underlying Mechanism ◽  
Steel Fibers ◽  
Flexural Behavior ◽  
Steel Wool ◽  
Multi Scale ◽  
Pull Out ◽  
Fiber Matrix

Steel fibers are typically used in ultra-high performance concretes (UHPC) to impart flexural ductility and increase fracture toughness. However, the mechanical properties of the steel fibers are underutilized in UHPC, as evidenced by the fact that most of the steel fibers pull out of a UHPC matrix largely undamaged during tensile or flexural tests. This research aims to improve the bond between steel fibers and a UHPC matrix by using steel wool. The underlying mechanism for fiber-matrix bond improvement is the reinforcement of the matrix tunnel, surrounding the steel fibers, by steel wool. Single fiber pullout tests were performed to quantify the effect of steel wool content in UHPC on the fiber-matrix bond. Microscopic observations of pulled-out fibers were used to investigate the fiber-matrix interface. Compared to the control UHPC mixture with no steel wool, significant improvement in the flexural behavior was observed in the UHPC mixtures with steel wool. Thus, the addition of steel wool in steel fiber-reinforced UHPC provides multi-scale reinforcement that leads to significant improvement in fiber-matrix bond and mechanical properties of UHPC.

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 Reinforced with Short Steel and Carbon Fibers

2015 ◽  
Vol 1 ◽  
pp. 193 ◽  
Author(s):  
Genadijs Šahmenko ◽  
Andrejs Krasnikovs ◽  
Artūrs Lukašenoks ◽  
Māris Eiduks
Keyword(s):  
Carbon Fibers ◽  
High Performance ◽  
Bending Strength ◽  
High Performance Concrete ◽  
Steel Fibers ◽  
Cement Matrix ◽  
Cracking Behavior ◽  
Combined Application ◽  
Pull Out ◽  
Bearing Stress

<p class="R-AbstractKeywords"><span lang="EN-US">Fibers are usually used in High Performance Concrete with a purpose to increase bending strength and ductility. Important properties are the peak value of bearing stress (strength) and post-cracking behavior of bended element. In the framework of an experimental part, Ultra High Performance mix compositions were prepared using intensive mixer. Short steel fibers and carbon micro fibers in amount of 1% by volume, as well as its combination were used for cement matrix reinforcing. Results of compressive and bending tests proved an increase of strength value in the case of use both steel and carbon fibers. Carbon fibers were decreased the effect of explosive collapse of the UHPC cement matrix, at the same time still brittle bending behavior was take place. Steel fibers considerably improved bending ductility thanks to a pull-out mechanism of steel fibers. The best results were achieved in the case of combined application of both carbon and steel fibers.</span></p>

scholarly journals A Review on the Study of Strength Properties of High Performance Concrete Using Various Fibers

2019 ◽  
pp. 411-415
Author(s):  
Venkateshwaran S ◽  
Alex Rajesh A
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
High Performance ◽  
High Performance Concrete ◽  
Strength Properties ◽  
Strength Test ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Compressive Strength Test ◽  
Pet Fibers

This is review report on High performance Concrete and is done by studying various journal papers on High performance concrete and this paper mainly concentrated on how to improve the Strength of concrete by using various fibers. Fibers are generally used in concrete to improve the tensile strength of the concrete. In fiber Reinforced Concrete (FRC) various types of fibers can be used such as polypropylene, cellulose, carbon, jute, PET fibers and Steel fibers. Among the above all steel fibers shows best performance comparing to other fibers. The flexural strength and compressive strength test are commonly done for every fiber and their values and comparisons are discussed in this report.

scholarly journals Analysis of Abrasion Depth and Rates in Concrete

2021 ◽  
Vol 15 (6) ◽  
pp. 1
Author(s):  
Mohammed Saleh AlAnsari
Keyword(s):  
Comparative Analysis ◽  
High Performance ◽  
High Performance Concrete ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Hydraulic Structures ◽  
Polypropylene Fibers ◽  
New Techniques ◽  
Different Types ◽  
High Performance Fiber

Abrasion is a major problem in hydraulic structures as they are continuously exposed to various types of water. Henceforth, these structures are susceptible to damage and require heavy maintenance. There is a significant demand in finding new techniques for improving the resistance towards the erosion of the concrete used in the construction of hydraulic structures. This work put forth a comparative analysis of the performance of two different types of concretes towards resistance namely, high-performance fiber reinforced concrete (HPFRC) [steel fibers (30 mm and 50 mm) and polypropylene fibers (19 mm)] and high-performance concrete (HPC). A comparative study was carried out based on their resistance towards wearing and hydro-abrasion erosion. The analyses were conducted using the WMP ECLIPSE method and ASTM C 1138 method. The results indicated that the rate of abrasion could be diminished by 18% based on the types of cement, fibers, concrete and modifications like the addition of silica fume.&nbsp;

Investigation on Toughness of Fibre Cocktail Reinforced Self Consolidating Concrete after High Temperature

2010 ◽  
Vol 650 ◽  
pp. 67-77
Author(s):  
Yi Ning Ding ◽  
Yue Hua Wang ◽  
Yu Lin Zhang
Keyword(s):  
High Temperature ◽  
High Performance ◽  
Steel Fibers ◽  
Failure Pattern ◽  
Self Consolidating Concrete ◽  
Pull Out ◽  
Hybrid Fibre ◽  
Before And After ◽  
Higher Temperature ◽  
Lower Temperature

The effect of different fibres on the residual load-bearing capacity and the failure pattern of high-performance self consolidating concrete (HPSCC) after exposure to high temperature hass been studied in this work. The polypropylene fibers mitigate the spalling of HPSCC element clearly, but did not show clear effect on the mechanic properties of concrete. The macro steel fiber reinforced HPSCC showed higher flexural toughness and ultimate load before and after high temperatures. The mechanical properties of hybrid fibre reinforced HPSCC (HFHPSCC) after heating were better than that of mono-fibre reinforced HPSCC. The failure mode changed from pull-out of steel fibers at lower temperature to broken down of steel fibers at higher temperature. The use of hybrid fibre can be effective in providing the residual strength and failure pattern, and improving the toughness of HPSCC after high temperature.

scholarly journals Steel Fiber Use as Shear Reinforcement on I-Shaped UHP-FRC Beams

2019 ◽  
Vol 9 (24) ◽  
pp. 5526 ◽  
Author(s):  
Umut Hasgul ◽  
Altug Yavas ◽  
Tamer Birol ◽  
Kaan Turker
Keyword(s):  
Failure Mode ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Reference Beam ◽  
Fiber Reinforced Concrete ◽  
Steel Fibers ◽  
Shear Reinforcement ◽  
Steel Fiber Reinforced Concrete ◽  
Loading Test

In the presented paper, the effectiveness of steel fiber use on the shear and flexure behaviors of ultra-high performance concrete (UHPC) beams and the feasibility of steel fibers in place of shear reinforcement were investigated experimentally. In this framework, a total of four I-shaped UHPC beams were produced for a high tensile reinforcement ratio of 2.2%. While two of them were non-fiber UHPC beams with and without the shear reinforcement to show the contribution of steel fibers, the remaining beams were made from the ultra-high performance steel fiber-reinforced concrete (UHP-FRC) having the short straight fibers with 1.5% and 2.5% by volume. The shear and flexural parameters, such as the load–deflection response, cracking pattern, failure mode, deflection, and curvature ductilities were discussed based on the four-point loading test results. While the reference beam without fiber and shear reinforcement failed by the shear with a sudden load drop before the yielding of reinforcement and produced no deflection capability, the inclusion of steel fibers to the UHPC matrix transformed the failure mode from shear to flexure through the fibers’ crack-bridging ability. It might be deduced that the moderate level of steel fiber use in the UHP-FRC beams may take the place of shear reinforcement in practical applications.

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