Numerical Study of the Bond Strength Evolution of Corroded Reinforcement in Concrete in Pull-Out Tests

The corrosion of rebars in reinforced concrete structures impacts their geometry (diameter and ribs) and mass, damages the concrete at the interface between the two materials, deteriorates the bond strength, and causes the cracking of the concrete cover. In the following study, a 2D numerical model of the pull-out test is presented in order to study the impact of corrosion on the bond strength. Several parameters are investigated: the embedment depth, the rebar’s diameter, and the width of the concrete cover. The model reproduces the slip of the rebar and the failure through the splitting of concrete. It integrates an interface between the two materials and a concrete damage model that simulate the deterioration of concrete in compression and tension. The results obtained are validated with experimental data from the literature. Moreover, a parametric study is carried out to determine the impact of the embedment depth, the diameter of the rebar, and the concrete cover on the bond strength. The present study confirms that a greater embedment depth increases the pulling load. The study also confirms that the rebar’s diameter impacts highly the loss of bond between the rebar and the concrete cover. Lastly, the final main result of this paper is that the width of the concrete cover slows the loss of bond strength between the two materials.

Download Full-text

Influence of Test Configuration on Bond Strength of GFRP Bars

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.292.217 ◽

2019 ◽

Vol 292 ◽

pp. 217-223 ◽

Cited By ~ 1

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.

Download Full-text

A Numerical Study on the Pull-Out Strengths of Anchor Bolts Embedded in Concrete Using the Smoothed Particle Hydrodynamics Method

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.711.1111 ◽

2016 ◽

Vol 711 ◽

pp. 1111-1117 ◽

Cited By ~ 1

Author(s):

Yoshimi Sonoda

Keyword(s):

Smoothed Particle Hydrodynamics ◽

Failure Modes ◽

Numerical Study ◽

Failure Process ◽

Embedment Depth ◽

Anchor Bolt ◽

Pull Out ◽

Particle Hydrodynamics ◽

Smoothed Particle ◽

Anchor Bolts

The strength of an anchor bolt in concrete structure under pull-out load is usually designed by three possible failure modes such as fracture of anchor bolt, cone failure of concrete and bond failure between anchor bolt and concrete. In general, the design load is considered the smallest load corresponding to the aforementioned failure mechanisms. However, unexpected failure often occurs in the anchorage zone due to the complex failure or the change of failure condition. Therefore, it is important to develop the accurate analysis method of ultimate load bearing capacity of the anchor bolt. In this study, we conducted an analytical study using Adaptive Smoothed Particle Hydrodynamics (ASPH) in order to simulate the failure process of anchorage zone and discussed the effect of embedment depth of anchor bolts on their ultimate strength.

Download Full-text

The influence of total reinforcement anchorage length on misinterpretation of the impact of hot-dip galvanised steel corrosion on its bond strength with concrete

Koroze a ochrana materialu ◽

10.1515/kom-2016-0003 ◽

2016 ◽

Vol 60 (1) ◽

pp. 13-20 ◽

Cited By ~ 1

Author(s):

P. Pokorný ◽

J. Čech ◽

P. Tej ◽

M. Vokáč

Keyword(s):

Bond Strength ◽

Negative Impact ◽

Steel Corrosion ◽

Anchorage Length ◽

Pull Out ◽

Galvanised Steel ◽

Strength Tests ◽

Short Test ◽

The Impact ◽

Total Reinforcement

Abstract To begin with, the intorduction of this paper summarises literature sources that wrongly interpret results of the bond strength between hot-dip galvanised reinforcements and concrete. The influence of the total reinforcement anchorage length on the bond strength results assessment was studied in detail. The numeric analysis of beam models with various testing anchorage lengths (the analysis input data comprised the results of previous bond strength tests carried out in a laboratory) unambiguously confirmed that when the bond strength between concrete and hot-dip galvanised reinforcement with a sufficient test anchorage length is tested in a beam test, the negative impact of the coating corrosion on bond strength with concrete may be biased. It is more objective to test bond strength with concrete in a pull-out test where a very short test reinforcement anchorage length is set out as a standard.

Download Full-text

Bond Behaviour Between Reinforcing Bars and Geopolymer Concrete By Using Pull-out Test

MATEC Web of Conferences ◽

10.1051/matecconf/201928004008 ◽

2019 ◽

Vol 280 ◽

pp. 04008

Author(s):

Ratni Nurwidayati ◽

Januarti Ekaputri ◽

Triwulan ◽

Priyo Suprobo

Keyword(s):

Bond Strength ◽

Sodium Hydroxide ◽

Concrete Cover ◽

Raw Material ◽

Maximum Diameter ◽

Geopolymer Concrete ◽

Bond Behaviour ◽

Reinforcing Bar ◽

Pull Out ◽

Bar Diameter

This paper presents the effect of the reinforcing bar diameter (db) and concrete cover thickness to reinforcing bar diameter ratio (c/db) to the bond strength between reinforcing bar and geopolymer concrete by using the experimental pull-out test. The mass ratio of sodium hydroxide (NaOH) to sodium silicate (Na2SiO3) was 2.5 with an 8 M concentration of sodium hydroxide were used in this research. Class F fly ash from Suralaya Power Station, Banten, Indonesia was used as raw material to produce geopolymer concrete. The maximum diameter of coarse aggregate was 10 mm. The result indicated that the maximum pull-out load on reinforcing bar diameter of 16 mm was higher than the diameter of 13 mm. The pull-out failure occurred on the ratio of c/db more than equal of 4.3. The bond strength increased as the ratio of c/db increased, up to 4.3. However, more than 4.3 was the insignificant effect.

Download Full-text

An Experimental and Numerical Study of the Dynamic Fracture of Glass

Volume 1: Advanced Packaging; Emerging Technologies; Modeling and Simulation; Multi-Physics Based Reliability; MEMS and NEMS; Materials and Processes ◽

10.1115/ipack2013-73292 ◽

2013 ◽

Cited By ~ 2

Author(s):

Liang Xue ◽

Yuling Niu ◽

Hohyung Lee ◽

Da Yu ◽

Satish Chaparala ◽

...

Keyword(s):

Dynamic Fracture ◽

Numerical Study ◽

Damage Model ◽

Experimental Studies ◽

Image Correlation ◽

Fea Model ◽

Glass Fracture ◽

Impact Area ◽

The Impact ◽

Dynamic Impact Loading

The needs of glass to resist the scratches, drops impact, and bump from everyday use lead to the importance of investigation of the glass fracture under dynamic impact loading. The strength of the glass under dynamic fracture conditions is significantly larger than that under quasi-static loading. There are several theoretic models. In this study, an accumulated damage model is implemented. The relation among the stress, loading rate, contact time and the fracture is investigated. The effect of impact area, impact energy and impact momentum on the glass fracture has been proved to further improve the dynamic fracture criterion of glass. For the experimental studies, the Digital Image Correlation (DIC) method enables one to obtain the first principal strain of the glass during the impact process. Moreover, the FEA model is developed in ANSYS/LS-DYNA™.

Download Full-text

Effect of Stirrup on Bond Strength Degradation in Concrete Cracked by Expansion Agent Filled Pipes

Applied Sciences ◽

10.3390/app11198874 ◽

2021 ◽

Vol 11 (19) ◽

pp. 8874

Author(s):

Amadou Sakhir Syll ◽

Hiroki Shimokobe ◽

Toshiyuki Kanakubo

Keyword(s):

Bond Strength ◽

Crack Width ◽

Strength Degradation ◽

Structural Safety ◽

Volumetric Expansion ◽

Pull Out ◽

Proposed Model ◽

Coefficients Of Variation ◽

Bond Degradation ◽

The Impact

The corrosion of rebars in reinforced concrete structures cracks the concrete, which leads to the degradation of the bond strength between the rebar and concrete. Since bond deterioration can menace structural safety, bond strength evaluation is essential for proper maintenance. In this study, the authors investigated bond strength degradation by conducting pull-out tests on concrete specimens, with induced crack width and stirrups ratio being the principal parameters. An expansion agent-filled pipe (EAFP) simulates cracks due to the volumetric expansion of the corroded rebar. One advantage of this method is that it allows one to focus on the single effect of an induced crack. The pull-out tests on 36 specimens show that stirrups’ confinement significantly influences the bond degradation due to induced cracks. The authors proposed an empirical model for the degradation of bond strength, considering the impact of induced crack width. The result shows that the induced crack by EAFP can quantify the exclusive consequence of corrosion on bonds. Furthermore, the coefficient of variation is 12% for specimens without stirrup from Law et al. For specimen without and with stirrup from Lin et al., the coefficients of variation are 14% and 17%. The proposed model can predict the corroded specimen from the literature with reasonable accuracy.

Download Full-text

Bond Strengths of Geopolymer and Cement Concretes

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.69.143 ◽

2010 ◽

Vol 69 ◽

pp. 143-151 ◽

Cited By ~ 8

Author(s):

Prabir Sarker

Keyword(s):

Reinforced Concrete ◽

Bond Strength ◽

Concrete Cover ◽

Reinforced Concrete Structures ◽

Geopolymer Concrete ◽

Reinforcing Steel ◽

Test Results ◽

Reinforcing Bars ◽

Pull Out ◽

Bar Diameter

Geopolymer is an inorganic alumino-silicate product that shows good bonding properties. Geopolymer binders are used together with aggregates to produce geopolymer concrete which is an ideal building material for infrastructures. A by-product material such as fly ash is mixed together with an alkali to produce geopolymer. Current research on geopolymer concrete has shown potential of the material for construction of reinforced concrete structures. Structural performance of reinforced concrete depends on the bond between concrete and the reinforcing steel. Design provisions of reinforced concrete as a composite material are based on the bond strength between concrete and steel. Since geopolymer binder is chemically different from Ordinary Portland Cement (OPC) binder, it is necessary to understand the bond strength between geopolymer concrete and steel reinforcement for its application to reinforced concrete structures. Pull out test is commonly used to evaluate the bond strength between concrete and reinforcing steel. This paper describes the results of the pull out tests carried out to investigate the bond strength between fly ash based geopolymer concrete and steel reinforcing bars. Beam end specimens in accordance with the ASTM Standard A944 were used for the tests. In the experimental program, 24 geopolymer concrete and 24 OPC concrete specimens were tested for pull out. The concrete compressive strength varied from 25 to 55 MPa. The other test parameters were concrete cover and bar diameter. The reinforcing steel was 500 MPa steel deformed bars of 20 mm and 24 mm diameter. The concrete cover to bar diameter ratio varied from 1.71 to 3.62. It was found from the test results that the failure occurred by splitting of concrete in the region bonded with the steel bar, in both geopolymer and OPC concrete specimens. Comparison of the test results shows that geopolymer concrete has higher bond strength than OPC concrete. This suggests that the existing design equations for bond strength of OPC concrete with steel reinforcing bars can be conservatively used for calculation of bond strength of geopolymer concrete.

Download Full-text

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

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.711.673 ◽

2016 ◽

Vol 711 ◽

pp. 673-680 ◽

Cited By ~ 2

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.

Download Full-text

Pullout simulation of post installed chemically bonded anchors in UHPFRC

MATEC Web of Conferences ◽

10.1051/matecconf/201819911007 ◽

2018 ◽

Vol 199 ◽

pp. 11007

Author(s):

Fabien Delhomme ◽

Michael Brun

Keyword(s):

Numerical Model ◽

High Performance ◽

Failure Modes ◽

Numerical Study ◽

Design Stage ◽

Embedment Depth ◽

Concrete Damage ◽

Pullout Failure ◽

Set Up ◽

Good Agreement

An experimental and numerical study was completed in order to examine the mechanical behaviour of post-installed bonded anchors in ultra-high performance fibre reinforced concrete with a compressive strength higher than 130 MPa. The aim was to analyse the failure mechanisms in static pullout tests and to suggest a simple numerical model, which can be employed in a design stage, to reproduce the global behaviour of the anchor. The experimental observations show that a combined pullout and concrete cone failure occurred for an embedment depth of 40 mm and a steel rod failure for an embedment depth of 100 mm. The numerical model was set up using Abaqus software, by adopting the concrete damage plastic model and a surface-based cohesive behaviour for the interface concrete-anchor. The obtained failure modes and ultimate loads are in good agreement with experimental results. A minimum embedment depth of 50 mm was assessed to prevent a pullout failure of the anchor.

Download Full-text

Behavior of bladder-type inflatable anchors in sand: Physical modeling

Science Progress ◽

10.1177/00368504211015106 ◽

2021 ◽

Vol 104 (2) ◽

pp. 003685042110151

Author(s):

Wang Lichang ◽

Xu Meng ◽

Peng Wenxiang ◽

Long Wei ◽

Shou Keh-Jian ◽

...

Keyword(s):

Film Thickness ◽

Test Chamber ◽

Primary Objective ◽

Embedment Depth ◽

Inflation Pressure ◽

Foundation Pit ◽

Pull Out ◽

The Impact ◽

Rubber Film ◽

Ultimate Displacement

This paper describes an investigation into the performance and pull-out capacity of a bladder-type inflatable anchor. The inflatable anchor is a type of support member used in foundation pit support engineering. Based on improvements and innovations, the multi-bladder-type inflatable anchor consists of two or more hydraulically inflated rubber membranes that are embedded in unconsolidated earth and then inflated to provide pull-out capacity. The primary objective of this study was to investigate the impact of inflation pressure, embedment depth, number of bladders, bladder length, and rubber film thickness on the pull-out capacity and displacement of the inflatable anchor. The tests were carried out in a cylindrical steel test chamber filled with medium coarse sand. The pull-out behavior of the bladder-type inflatable anchor and the five variables was investigated, and the benchmark values for all tests are determined by similarity ratio. Compared with the single bladder inflatable anchor, under the same conditions, the ultimate pull-out capacity of the two bladder-type inflatable anchor is 1.2 times higher, with ultimate displacement only 37.5% of the former, the ultimate pull-out capacity of the three bladder-type inflatable anchor is 1.7 times higher, with ultimate displacement only 32.3% of the former. The two bladder-type inflatable anchor is superior to the single bladder inflatable anchor and the multi-bladder-type has higher ultimate pull-out capacity and greater stiffness. The inflation pressure and the rubber film thickness have a significant influence on the bearing capacity. The number of bladders effectively controls the ultimate displacement.

Download Full-text