Bond Behavior of FRP Bars in Concrete

2018 ◽  
Vol 272 ◽  
pp. 3-8 ◽  
Author(s):  
Ondřej Janus ◽  
Frantisek Girgle ◽  
Vojtech Kostiha ◽  
Petr Štěpánek
Keyword(s):  
Surface Treatment ◽  
Concrete Cover ◽  
Experimental Program ◽  
Direct Influence ◽  
Test Configuration ◽  
Bond Behavior ◽  
Pull Out ◽  
Frp Reinforcement ◽  
Cover Thickness ◽  
Frp Bars

This article deals with the bond of internal composite (FRP) reinforcement with different surface treatments. Bars with additional sand-coating exhibit different behavior due to different transmission of forces in relation to bars with ribbed surface. To compare the bond behavior of these types of reinforcement, an experimental program consisting of several sets of pull-out tests was designed. This test configuration was chosen primarily for simplicity, comparability with previously published results, and especially easy modification for assessment the effect of concrete cover thickness. The paper presents the results confirming the direct influence of the surface treatment and also the position of the reinforcement on the resulting bond behavior.

Influence of Test Configuration on Bond Strength of GFRP Bars

2019 ◽  
Vol 292 ◽  
pp. 217-223 ◽  
Author(s):  
Ondřej Janus ◽  
Frantisek Girgle ◽  
Vojtech Kostiha ◽  
Petr Štěpánek ◽  
Pavel Sulak
Keyword(s):  
Bond Strength ◽  
Concrete Cover ◽  
Silica Sand ◽  
Beam Test ◽  
Bond Behaviour ◽  
Test Configuration ◽  
Gfrp Bars ◽  
Pull Out ◽  
Frp Reinforcement ◽  
Gfrp Reinforcement

It is well-known that test configuration affects bond behaviour of steel reinforcement, but this effect has not yet been sufficiently quantified when using FRP reinforcement. This paper presents partial results from an ongoing experimental programme that deals with the bond strength of GFRP bars with concrete, with regards to the effect of the surface treatment of the rebars and test configuration. A modified beam test is presented in this study along with a pull-out test with an eccentric bar placement. The bond strength of GFRP reinforcement with sand-coated treatment using silica sand and ribbed type with milled ribs was tested. The sand-coated bars exhibit different bond behaviour compared to the ribbed ones due to different forces transfer from the reinforcement to the concrete. Thickness of the concrete cover layer also has a significant effect on the bond behaviour of the reinforcement.

scholarly journals Surface treatment systems for concrete in marine environment: Effect of concrete cover thickness

2016 ◽  
Vol 69 (3) ◽  
pp. 287-292 ◽  
Author(s):  
Marcelo Henrique Farias de Medeiros ◽  
Eduardo Pereira ◽  
Valdecir Angelo Quarcioni ◽  
Paulo Roberto do Lago Helene
Keyword(s):  
Surface Treatment ◽  
Marine Environment ◽  
Concrete Cover ◽  
Environment Effect ◽  
Cover Thickness

Experimental Study on Bond-Slip between Steel Bar and Recycled Aggregate Concrete

2011 ◽  
Vol 250-253 ◽  
pp. 1651-1656 ◽  
Author(s):  
Qing Feng Huang ◽  
Da Fu Wang
Keyword(s):  
Concrete Strength ◽  
Concrete Cover ◽  
Recycled Concrete ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Aggregate Concrete ◽  
Bond Slip ◽  
Pull Out ◽  
Steel Bar ◽  
Cover Thickness

By a static and repeated pull-out experiment between steel bar and recycled aggregate concrete, and bond-slip curves between recycled concrete with different recycled coarse aggregate(RCA) replacement percentages were recorded. Based on the analysis of the experimental results, replacement percentages of recycled concrete, cover thickness, anchorage length, concrete strength and loading method was investigated. At last, the bond-slip constitutive relation was also discussed.

Acoustic emission monitoring for bond integrity evaluation of reinforced concrete under pull-out tests

2016 ◽  
Vol 20 (9) ◽  
pp. 1390-1405 ◽  
Author(s):  
Ahmed A Abouhussien ◽  
Assem AA Hassan
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Acoustic Emission Signal ◽  
Concrete Structures ◽  
Signal Strength ◽  
Concrete Cover ◽  
Reinforced Concrete Structures ◽  
Bond Behavior ◽  
Emission Signal ◽  
Pull Out

This article presents the results of an experimental investigation on the application of acoustic emission technique for monitoring the steel-to-concrete bond integrity of reinforced concrete structures. A series of direct pull-out tests were performed on 54 reinforced concrete unconfined prism samples with variable rebar diameter (10, 20, and 35 mm), embedded length (50, 100, and 200 mm), and concrete cover (20, 30, and 40 mm). The samples were tested under incrementally increasing monotonic loading while being continuously monitored via attached acoustic emission sensors. These sensors were utilized to acquire different acoustic emission signal parameters emitted throughout the tests until failure. Also, an acoustic emission intensity analysis was implemented on acoustic emission signal strength data to quantify the damage resulting from loss of bond in all tested specimens. This analysis employed the signal strength of all recorded acoustic emission hits to develop two additional parameters: historic index ( H ( t)) and severity ( Sr). The results of bond behavior, mode of failure, and free end slip were compared with the recorded acoustic emission data. The results showed that the cumulative number of hits, cumulative signal strength, H ( t), and Sr had a good correlation with different stages of bond damage from de-bonding/micro-cracking until bond splitting failure and bar slippage, which caused cover cracking or delamination. The analysis of cumulative signal strength and H ( t) curves enabled early identification of two progressive stages of bond degradation (micro-cracking and macro-cracking) and recognized the various modes of failure of the tested specimens. The variations of bar diameter, concrete cover, and embedded length yielded significant impacts on both the bond behavior and acoustic emission activities. The results also presented developed intensity classification charts, based on H ( t) and Sr, to assess the bond integrity and to quantify the bond deterioration (micro-cracking, macro-cracking, and rebar slip) in reinforced concrete structures.

The Analysis of the Reliability and Design for Mechanical Anchorage of HRB500 Steel Bars

2011 ◽  
Vol 94-96 ◽  
pp. 970-974
Author(s):  
Xian Rong ◽  
Peng Cheng Liu ◽  
Xue Li
Keyword(s):  
Concrete Strength ◽  
Concrete Cover ◽  
Statistical Regression ◽  
Analysis Method ◽  
Anchorage Length ◽  
Pull Out ◽  
Steel Bar ◽  
Steel Bars ◽  
Mechanical Anchoring ◽  
Cover Thickness

The factors on mechanical anchoring performance of HRB500 steel bars, such as concrete strength, concrete cover thickness, diameter of steel bar, anchorage length of steel bar and transverse reinforcement ratio, were studied based on pull-out tests of 45 specimens. And the formula of mechanical anchoring bond strength for HRB500 steel bars was concluded by statistical regression analysis method. Through the reliability analysis, the mechanical anchoring length of design value and the table of conversion ratio between mechanical and direct anchoring length of HRB500 steel bars have been proposed. So it could be used as a basis for practical projects. The results indicate that the mechanical anchorage length of HRB500 steel bars can be still designed with the formula proposed in GB 50010-2002 “Code for design of concrete structures”.

scholarly journals Finite element analysis on the bond behavior of steel bar in salt–frost-damaged recycled coarse aggregate concrete

2021 ◽  
Vol 60 (1) ◽  
pp. 853-861
Author(s):  
Tian Su ◽  
Ting Wang ◽  
Haihe Yi ◽  
Rui Zheng ◽  
Yizhe Liu ◽  
...  
Keyword(s):  
Bond Strength ◽  
Concrete Cover ◽  
Bond Slip ◽  
Bond Behavior ◽  
Steel Bar ◽  
Calculation Results ◽  
Cover Thickness ◽  
Bar Diameter ◽  
Good Agreement ◽  
Ultimate Bond Strength

Abstract In this article, the ABAQUS finite element software is used to simulate the bond behavior of the steel bar in salt–frost-damaged recycled coarse aggregate concrete, and the influence of the steel bar diameter and the concrete cover thickness on the bond strength is investigated. The result shows that the calculated bond–slip curve is in good agreement with the experimental bond–slip curve; the mean value of the ratio of the calculation results of ultimate bond strength to the experiment results of ultimate bond strength is 1.035, the standard deviation is 0.0165, and the coefficient of variation is 0.0159, which proves that the calculation results of the ultimate bond strength are in good agreement with the experimental results; with the increase of steel bar diameter and the concrete cover thickness, the ultimate bonding strength of RAC and steel increases; the calculation formulas for the ultimate bond strength of specimens with different steel bar diameters (concrete cover thickness) after different salt–frost cycles are obtained.

scholarly journals Performance of Tension Lap-Splice in Lightweight Concrete

2020 ◽  
Vol 9 (3) ◽  
pp. 181-186
Keyword(s):  
Failure Modes ◽  
Lightweight Concrete ◽  
Cost Savings ◽  
Concrete Cover ◽  
Steel Reinforcement ◽  
Moment Capacity ◽  
Bond Behavior ◽  
Lap Splice ◽  
Cover Thickness ◽  
Bar Diameter

The use of Light-Weight Concrete (LWC) in modern construction has resulted in efficient designs and considerable cost savings by reducing structural own weight and supporting footings sections. The purpose of this paper is to investigate the Lap-Splice behavior between LWC and steel reinforcement (RFT). The tested specimens were divided into four groups to study the effect of main variables: steel reinforcement bar size, internal confinement (stirrups), splice length and concrete cover thickness. Four-point bending tests were carried out on test specimens to evaluate the performance of lap splices under pure bending. Bond behavior and failure modes were noted to be similar in the normal concrete and in the LWC. In tested beams, it was observed that the bar size has a significant influence on the mean bond stress in the splice. Improving radial tensile strength by using increasing stirrups number improves the bond behavior. The splice length up to 35 times bar diameter decreased the moment capacity of beam. The splice length of 55 times bar diameter results in the same capacity of the beam without any splice.

Experimental Study on Effects of Fatigue Loading History on Bond Behavior between Steel Bars and Concrete

2016 ◽  
Vol 711 ◽  
pp. 673-680 ◽  
Author(s):  
Zhiwen Ye ◽  
Wei Ping Zhang ◽  
You Hu ◽  
Xiang Lin Gu
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Fatigue Loading ◽  
Critical Value ◽  
Concrete Cover ◽  
Repeated Loading ◽  
Loading History ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bars

This paper presents an experimental investigation on the influence of fatigue loading history on bond behavior between steel bars and concrete. Reinforced concrete specimens were subjected to fatigue loadings with different amplitudes and cycles before undergoing eccentric pull-out tests. Tests revealed that all specimens failed with the splitting of the concrete cover. With increased loading cycles, the concrete in front of transverse ribs usually becomes denser at the beginning. Meanwhile, the initial bond stiffness and the bond strength increased, while the slip corresponding to the peak bond stress decreases. With the further increase of loading cycles, the bond strength begins to decrease after it reaches a critical value. This study determined that for specimens subjected to repeated loading with a larger amplitude, fewer cycles are needed for the bond strength to go up to the critical bond strength.

BOND BEHAVIOR OF LIGHTWEIGHT FIBER REINFORCED CONCRETE

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Klaus Holschemacher ◽  
Ahsan Ali ◽  
Shahid Iqbal
Keyword(s):  
Reinforced Concrete ◽  
Lightweight Concrete ◽  
Normal Weight ◽  
Fiber Reinforced Concrete ◽  
Experimental Program ◽  
Fiber Reinforced ◽  
Bond Behavior ◽  
Normal Weight Concrete ◽  
Air Content ◽  
Pull Out

In construction industry lightweight concrete and fiber reinforced concrete are being used for many years. The former is known for brittle nature, light in weight and low thermal conductivity properties. It also offers better workability when compared to the normal weight concrete for the same slump value. These properties are however affected by addition of discrete fibers. Among the affected properties is also the bond between steel and concrete surrounding it. The integrity of a reinforced concrete member is not ensured in the absence of adequate bond. Due to limited literature on the subject matter, an experimental program was carried out to understand the bond behavior in lightweight concrete after fiber inclusion. For the purpose modified pull-out specimens made of Lightweight Fiber Reinforced Concrete (LWFC) were tested. Hooked end steel fibers having length 35 mm and diameter 0.5 mm (l/d = 0.7) were incorporated in dosages of 0, 20, and 40 kg/m3. Besides pull-out specimens, testes were also carried out for fresh and hardened properties of LWFC. Tests results indicate higher pull-out loads for higher fiber contents. The average increase in ultimate bond strength was observed at 28% and 2% for 40 kg/m3 and 20 kg/m3 fiber contents respectively. The fresh concrete density, compressive strength of mixes reduced and air-content values increased with increase in fiber content.

BOND AND FLEXURAL BEHAVIOR OF SELF-CONSOLIDATING CONCRETE BEAMS REINFORCED WITH GFRP BARS

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Slamah Krem ◽  
Khaled Soudki
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Cover ◽  
Flexural Behavior ◽  
Self Consolidating Concrete ◽  
Gfrp Bars ◽  
Cover Concrete ◽  
Concrete Type ◽  
Cover Thickness ◽  
Frp Bars

Self-consolidating concrete (SCC) is widely used in the construction industry. SCC is a high-performance concrete with high workability and consistency allowing it to flow under its own weight without vibration. Despite the wide spread of SCC applications, bond behavior of FRP bars embedded in SCC beams has not been fully studied. This paper presents an experimental and analytical analysis of fifteen beams reinforced with glass fiber reinforced polymer (GFRP) bars. The test parameters were the concrete type, bar diameter, concrete cover thickness and embedment length. All beams were tested in four-point bending to failure. The average bond stresses of GFRP bars in SCC were found comparable to those in NVC. However, FRP bars embedded in SCC beams had higher bond stresses within uncracked region of the beams than those embedded in NVC beams. In contrast, GFRP bars in SCC had lower bond stresses than FRP bars in NVC within the cracked region. Results indicated that when cover concrete thickness dropped less than 2 db, the splitting bond failure is predominant.

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