Investigation of bond between lap-spliced steel bar and self-compacting concrete: The role of silica fume

2010 ◽  
Vol 37 (3) ◽  
pp. 420-428 ◽  
Author(s):  
Mehmet Karatas ◽  
Kazim Turk ◽  
Zulfu C. Ulucan
Keyword(s):  
Bond Strength ◽  
Silica Fume ◽  
Full Scale ◽  
Reinforcing Bars ◽  
Self Compacting Concrete ◽  
Normal Concrete ◽  
Steel Bar ◽  
Normalized Bond Strength ◽  
Constant Moment

In this study, normal concrete (NC) and four types of self-compacting concrete (SCC), in which cement was partially replaced by 5%, 10%, 15%, and 20% of silica fume (SF), were used to evaluate the effect of SF content on the bond strength of tension lap-spliced bars embedded in NC and SCC specimens. Therefore, 15 full-scale beam specimens (2000 × 300 × 200 mm3) were tested and 20 mm reinforcing bars were used with a 300-mm splice length as tension reinforcement. Each beam was designed with bars spliced in a constant moment region at midspan. It was found that the bond strength of the reinforcement embedded in SCC beams was higher than that of the reinforcement in NC beams, whilst the bond strength increased with increase in the replacement of cement by SF from 5% to 10%. Moreover, the beam specimens produced from SCC containing 5% SF had the highest normalized bond strength of 1.07 followed by SCC beams with 10% SF, 15% SF, NC beams, and 20% SF.

Jak zwiększyć przyczepność stal zbrojeniowa-beton?

BUILDER ◽  
2019 ◽  
Vol 258 (1) ◽  
pp. 65-67 ◽  
Author(s):  
Milena Kucharska
Keyword(s):  
Bond Strength ◽  
Silica Fume ◽  
High Performance ◽  
Reinforcing Bars ◽  
Bond Quality ◽  
Self Compacting Concrete ◽  
The Impact

The paper analyses the impact of casting direction of self-compacting concrete (SCC) on its bond quality to steel reinforcing bars. Tests were performed on high performance self-compacting concretes with different amount of silica fume to cement mass. Experiment was carried out on 480 mm height specimens, which allowed determining changes of bond condition along its height. The ribbed reinforcing bars have been placed perpendicularly to the direction of casting. Casting was performed from two points – from the bottom and the top of the form. Research has shown that casting from the bottom of the form improves bond strength and quality.

scholarly journals The Comparison of Bond Strength between Geopolymer Concrete and OPC Concrete for Plain Reinforcing Bars

2018 ◽  
Vol 159 ◽  
pp. 01017 ◽  
Author(s):  
Nuroji ◽  
Daniel Herdian Primadyas ◽  
Ilham Nurhuda ◽  
Muslikh
Keyword(s):  
Bond Strength ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Reinforcing Bars ◽  
Normal Concrete ◽  
Steam Power ◽  
Bond Behavior ◽  
Pull Out ◽  
Concrete Blocks ◽  
Class F Fly Ash

This paper describes the research on bond behavior of plain reinforcing bars in geopolymer and normal concrete. The geopolymer concrete in this research was made of class F fly ash taken from Tanjung Jati Electric Steam Power Plant (PLTU) with Sodium Hydroxide (NaOH) and Sodium Silicate (Na2SiO3) as alkaline activator, added in the mixture. The effect of bar size was studied by varying the bar diameter in range 10 mm to 19 mm. Each bar was casted in the center of concrete blocks made of geopolymer as well as normal concrete. Pull-out tests were carried out to the specimens that have reached 28 days of age. The test results show that the bond behavior of geopolymer concrete differs substantially from normal concrete, where geopolymer concrete has a higher bond strength when compared to normal concrete with identical concrete strengths.

scholarly journals Bond strength of epoxy coated bar splices confined with nominal lateral reinforcement

2013 ◽  
Vol 3 (1) ◽  
Author(s):  
Krishnamurthy Pandurangan ◽  
Gangolu Rao
Keyword(s):  
Bond Strength ◽  
Primary Objective ◽  
Reduction Factor ◽  
Full Scale ◽  
Epoxy Coating ◽  
Transverse Reinforcement ◽  
Test Results ◽  
Bar Test ◽  
Lateral Reinforcement ◽  
Constant Moment

AbstractFusion bonded epoxy coating is one of the methods used to protect steel against corrosion. The primary objective of this research reported in this paper is to evaluate the bond strength of epoxy coated bar splices confined with lateral reinforcement. Six full scale beams specimens, designed to fail in bond- splitting mode, were tested in positive bending. Each beam was reinforced with bars spliced in the constant moment region at mid span. The main variables were the amount of transverse reinforcement in the splice region and the coating to the bar. Test results indicate that transverse reinforcement improves the bond strength of coated bars and the ductility of the beams. The bond strength of coated bars is 93%, 72% and 59% of uncoated bars for confinement indices of 1.8, 1.4 and 1.26 respectively. Moreover, a bond reduction factor of 1.35 is suggested for use in code in place of 1.5,when the confinement index is greater than 1.4.

scholarly journals An Experimental Study of Bond Behavior of Micro Steel Fibers Added Self-compacting Concrete with Steel Reinforcement

2020 ◽  
Author(s):  
Abdul Salam ◽  
Shah Room ◽  
Shahid Iqbal ◽  
Khalid Mahmood ◽  
Qaiser Iqbal
Keyword(s):  
Bond Strength ◽  
Steel Fibers ◽  
Self Compacting Concrete ◽  
Bond Failure ◽  
Maximum Increase ◽  
Bond Behavior ◽  
Micro Cracks ◽  
Steel Bar ◽  
Experimental Values ◽  
Major Emphasis

The obstruction offered by the surrounding concrete to the pulling out of embedded steel bar is known as bond strength. Steel fibers addition to concrete improves its bond strength by arresting the cracks due to their bridging effect. Bond failure occurs when cracks in the surrounding concrete initiates, providing enough space for bar to be pulled-out. Micro steel fibers efficiently control the formation of micro cracks and may improve bond strength to a greater extent compared to the longer steel fibers. However, it reduces the workability of concrete which is of greater importance in case of self-compacting concrete (SCC). Reduction of workability is less pronounced when straight micro steel fibers are used due to their shorter lengths and straight geometry. Thus, different amount of straight micro steel fibers (0.25 %, 0.5 %, 0.75 %) were incorporated in to SCC to investigate their fresh and mechanical properties with major emphasis on the bond strength. Results indicate that steel fibers addition to SCC improve the splitting tensile strength and bond strength significantly with a maximum increase of 33.5 % and 54.9 % respectively with 0.75 % fibers addition. An equation is proposed for the calculation of bond strength with micro steel fibers addition to SCC with a maximum variation of 4 % to those of experimental values.

scholarly journals A study of the bond behavior of FRP bars in MPC seawater concrete

2020 ◽  
pp. 136943322095681
Author(s):  
Wen Sun ◽  
Yu Zheng ◽  
Linzhu Zhou ◽  
Jiapeng Song ◽  
Yun Bai
Keyword(s):  
Bond Strength ◽  
Potassium Phosphate ◽  
Fiber Reinforced Polymer ◽  
Reinforcing Bars ◽  
Bond Behavior ◽  
Reinforced Polymer ◽  
Steel Bar ◽  
Gfrp Bar ◽  
Frp Bar ◽  
Frp Bars

Using magnesium potassium phosphate cement (MPC) and fiber-reinforced polymer (FRP) bar to produce reinforced concrete can overcome the durability problems facing conventional steel reinforced PC concrete. In addition, FRP bar reinforced MPC concrete can also mitigate the CO2 emission issues caused by Portland cement (PC) production and the shortage of natural resources such as virgin aggregates and freshwater. This paper, therefore, is aimed at investigating the bond behavior of the FRP bars in MPC seawater concrete. The direct pullout tests were conducted with a steel bar, BFRP bar, and GFRP bar embedded into different concretes. The effects of reinforcing bars, type of concrete and mixing water on the bond behavior of FRP and steel bars were investigated and discussed. The results showed that the MPC concrete increases the bond strength of BFRP and GFRP bars by 51.06% and 24.42%, respectively, compared with that in PC concrete. Using seawater in MPC concrete can enhance the bond strength of GFRP bar by 13.75%. The damage interface of the FRP bar -MPC is more severe than that of PC with a complete rupture of the FRP ribs and peeling-off of the resin compared to that in steel reinforced MPC specimens. Moreover, the bond stress-slip models were developed to describe the bond behavior of MPC-FRP specimen, and the analytical results match well with the experimental data. In conclusion, the FRP bars showed better bond behavior in the MPC seawater concrete than that in the PC counterparts.

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