Effect of Electrochemical Chloride Extraction on the Bond Performance between Steel Bar and Concrete

2011 ◽  
Vol 243-249 ◽  
pp. 5536-5540 ◽  
Author(s):  
Yu Xia Guo ◽  
Jing Xing Gong
Keyword(s):  
Bond Strength ◽  
Current Density ◽  
Bond Performance ◽  
Steel Bar ◽  
Initial Content ◽  
Electrochemical Chloride Extraction ◽  
Electric Quantity

Based on beam specimens of 100mm×100mm×400mm, the effect of electrochemical chloride extraction (ECE) on bond performance between steel bar and concrete contaminated by chloride was studied by determining the bond strength of them. During the test, 1%, 2% and 3% NaCl by weight of cement were mixed into concrete to simulate chloride contamination. In the process of ECE, four kinds of current density (1, 2, 3, 5 A/m2of steel bar area) and electric quantity (500, 1000, 1500 and 3000 A.h/m2of steel bar area) were taken into account, respectively. It is indicated that the bond strength between steel bar and concrete was degraded after ECE treatment, the more the current and the electric quantity of ECE are, the more the loss of bond strength is, and the initial content of chloride in concrete has a little influence on the bond strength.

Experimental Research on Interfacial Bond Performance in Rock Anchor with High-Performance Grouting Medium

2012 ◽  
Vol 517 ◽  
pp. 932-938 ◽  
Author(s):  
Zhi Fang ◽  
Hong Qiao Zhang
Keyword(s):  
Rock Mass ◽  
Bond Strength ◽  
High Performance ◽  
Interfacial Bond ◽  
Interfacial Bond Strength ◽  
Bond Performance ◽  
Pull Out ◽  
Steel Bar ◽  
Reactive Powder ◽  
Ground Anchor

There exist the problems such as low bond strength and bad durability in the ordinary grouting slurry of the ground anchor system at present. The high-performance grouting mediums RPC (Reactive Powder Concrete) and DSP (Densified Systems containing homogeneously arranged ultrafine Particles) would become the potential replacement of grouting medium in ground anchor resulting from their high compressive strength, durability and toughness. Based on a series of pull-out tests on ground anchors with different high-performance grouting medium of RPC and DSP , different bond length in the construction field, the bond performance on the interfaces between anchor bolt (deformed steel bar) and grouted medium as well as between grouted medium and rock mass was studied. The results indicate that the interfacial bond strength between RPC or DSP and deformed steel bolt ranges within 23-31Mpa, far greater than that (about 2-3MPa) between the ordinary cementitious grout and deformed steel bar. Even though the interfacial bond strength between the grouted medium and rock mass of limestone was not obtained in the test since the failure mode was pull-out of those steel bar rather than the interface shear failure between grouted medium and rock mass, the bond stress on the interface reached 6.2-8.38 MPa, also far greater than the bond strength (about 0.1-3MPa) between the ordinary cementitious slurry and rocks.

Effects of Hydrogen Evolution During ECE on the Bond Strength between Steel and Concrete

2012 ◽  
Vol 602-604 ◽  
pp. 952-956
Author(s):  
Chun Lin Deng ◽  
Yun Xu ◽  
Jian Bo Xiong ◽  
Sheng Nian Wang
Keyword(s):  
Adverse Effects ◽  
Bond Strength ◽  
Hydrogen Evolution ◽  
Current Density ◽  
Concrete Surface ◽  
Total Charge ◽  
Steel Reinforced Concrete ◽  
Pull Out ◽  
Electrochemical Chloride Extraction ◽  
Corrosion Of Steel

Electrochemical Chloride Extraction (ECE) is a new method to halt the corrosion of steel in concrete contaminated by chloride. The bond strength between steel and concrete with and without ECE were tested through steel pull-out test, and the effects of current density and total charge passed during ECE on it were analyzed. A demo device was designed to analyze the hydrogen evolution during ECE by dividing the cathode reactions and anode reactions into two sealed bottles. The relation between hydrogen content and electrons passed in the circuit and the adverse effects of the hydrogen on steel reinforced concrete was conducted. Through drilling appropriate number of holes from concrete surface into the steel, some hydrogen can be released and its adverse effects can be mitigated in a certain degree.

scholarly journals Study on the potential change of corroded reinforced concrete in ECE with MPC-CFRP as anode

2020 ◽  
Vol 319 ◽  
pp. 06005
Author(s):  
Yue Li ◽  
Xiuhu Zhang ◽  
S.M.Ali S. Hejazi
Keyword(s):  
Composite Material ◽  
Reinforced Concrete ◽  
Current Density ◽  
Good Effect ◽  
Steel Bar ◽  
Steel Bars ◽  
Cfrp Composite ◽  
Current Densities ◽  
Electrochemical Chloride Extraction ◽  
Corrosion Of Steel

Aiming at the rust removal requirements of reinforced concrete, the MPC-CFRP composite material was used as the external anode, and the Electrochemical chloride extraction (ECE) method was used to test the polarization curve of the steel bar under different ECE current densities, and the potential changes of the steel bar at different times were analyzed. The results show that the ECE system with MPC-CFRP as the external anode has a good effect of reducing the corrosion rate and the risk of corrosion of steel bars. The current density of 3A/m2is higher than that of 1A/m2in dechlorination efficiency. After 28 days of ECE, the current density of 1A/m2and 3A/m2can re passivate the reinforcement.

scholarly journals Early-Age Tensile Bond Characteristics of Epoxy Coatings for Underwater Applications

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 757 ◽  
Author(s):  
Kim ◽  
Hong ◽  
Han ◽  
Kim
Keyword(s):  
Bond Strength ◽  
Surface Treatment ◽  
Epoxy Resin ◽  
Coating Thickness ◽  
Experimental Results ◽  
Early Age ◽  
Curing Time ◽  
Bond Performance ◽  
Coating Type ◽  
Bond Characteristics

In this study, coating equipment for the effective underwater repair of submerged structures was developed. The tensile bond characteristics of selected epoxy resin coatings were investigated by coating the surface of a specimen using each of the four types of equipment. Using the experimental results, the tensile bond strength and the coating thickness were analyzed according to the type of equipment, coating, and curing time. The results show that the type of coating equipment used had the greatest effect on the measured bond strength and coating thickness of the selected coatings. However, the effect of coating type and curing time on the bond strength and the thickness was observed to be insignificant. Compared with the developed equipment, the surface treatment of the coating was observed to be more effective when using the pre-existing equipment, and thus the bond performance of the coating was improved compared to using the pre-existing equipment. Based on the experimental results, improvements and needs involving the equipment for further research were discussed.

scholarly journals Research on bond–slip performance between pultruded glass fiber-reinforced polymer tube and nano-CaCO3 concrete

2020 ◽  
Vol 9 (1) ◽  
pp. 637-649 ◽  
Author(s):  
Zhan Guo ◽  
Qingxia Zhu ◽  
Wenda Wu ◽  
Yu Chen
Keyword(s):  
Bond Strength ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Slip ◽  
Ordinary Concrete ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Push Out

AbstractThe article describes an experimental study on the bond–slip performance between the pultruded glass fiber-reinforced polymer (GFRP) tube and the nano-CaCO3 concrete. Taking the nano-CaCO3 concrete strength and GFRP tube thickness as primary parameters, nine specimens were designed and tested to study the influence of these parameters on the bond strength of the specimens. Besides, three specimens filled with the ordinary concrete were also tested by using the push-out tests to make comparisons with the bond performance of the specimens filled with nano-CaCO3 concrete. A total of four push-out tests were conducted on each specimen. The experimental results indicate that there are two types of axial load–slip curves for each specimen in four push-out tests. Moreover, comparison of the results of the push-out tests in the same direction shows that the bond failure load of the specimen decreases with the increase in the number of push-out tests. Based on the analysis of the test results, it is shown that the bond performance between the GFRP tube and the nano-CaCO3 concrete is better than that between the GFRP tube and the ordinary concrete. Furthermore, as the nano-CaCO3 concrete strength increases, the bond strength of the specimens decreases, indicating that the concrete strength has a negative effect on the bond strength. When the nano-CaCO3 concrete strength is relatively smaller (C20), the bond strength of the specimens decreases with the increase in the thickness of the GFRP tube. However, when the nano-CaCO3 concrete strength is relatively larger (C30 and C40), the bond strength of the specimens increases as the thickness of the GFRP tube increases.

Bond performance of GFRP and deformed steel hybrid bar with sand coating to concrete

2016 ◽  
Vol 36 (6) ◽  
pp. 464-475 ◽  
Author(s):  
Minkwan Ju ◽  
Gitae Park ◽  
Sangyun Lee ◽  
Cheolwoo Park
Keyword(s):  
Glass Fiber ◽  
Modulus Of Elasticity ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Polymer Hybrid ◽  
Reinforced Polymer ◽  
Glass Fiber Reinforced ◽  
Steel Bar

In this study, we experimentally investigated the bond performance of a glass fiber-reinforced polymer hybrid bar with a core section comprising a deformed steel bar and a sand coating. The glass fiber-reinforced polymer and deformed steel hybrid bar (glass fiber-reinforced polymer hybrid bar) can contribute to longer durability and better serviceability of reinforced concrete members because of the increased modulus of elasticity provided by the deformed steel bar. Uniaxial tensile tests in compliance with ASTM D 3916 showed that the modulus of elasticity of the glass fiber-reinforced polymer hybrid bar was enhanced up to three times. For the bond test, a total of 30 specimens with various sand-coating and surface design parameters such as the size of the sand particles (0.6 mm and 0.3 mm), sand-coating type (partially or completely), number of strands of fiber ribs (6 and 10), and pitch space (11.4 mm to 29.1 mm) of the fiber ribs were tested. The completely sand-coated glass fiber-reinforced polymer hybrid bar exhibited a higher bond strength (90.5%) than the deformed steel bar and a reasonable mode of failure in concrete splitting. A modification parameter to the Eligehausen, Popov, and Bertero (BPE) model is suggested based on the representative experimental tests. The bond stress–slip behavior suggested by the modified BPE model in this study was in reasonable agreement with the experimental results.

Utilizing alkali-activated materials as ordinary Portland cement replacement to study the bond performance of fiber-reinforced polymer bars in seawater sea-sand concrete

2022 ◽  
pp. 136943322110651
Author(s):  
Ruiming Cao ◽  
Bai Zhang ◽  
Luming Wang ◽  
Jianming Ding ◽  
Xianhua Chen
Keyword(s):  
Tensile Strength ◽  
Bond Strength ◽  
Ordinary Portland Cement ◽  
Concrete Strength ◽  
Fiber Reinforced Polymer ◽  
Bond Performance ◽  
Reinforced Polymer ◽  
Sea Sand ◽  
Frp Bars ◽  
Alkali Activated

Alkali-activated materials (AAMs) are considered an eco-friendly alternative to ordinary Portland cement (OPC) for mitigating greenhouse-gas emissions and enabling efficient waste recycling. In this paper, an innovative seawater sea-sand concrete (SWSSC), that is, seawater sea-sand alkali-activated concrete (SWSSAAC), was developed using AAMs instead of OPC to explore the application of marine resources and to improve the durability of conventional SWSSC structures. Then, three types of fiber-reinforced polymer (FRP) bars, that is, basalt-FRP, glass-FRP, and carbon-FRP bars, were selected to investigate their bond behavior with SWSSAAC at different alkaline dosages (3%, 4%, and 6% Na2O contents). The experimental results manifested that the utilization of the alkali-activated binders can increase the splitting tensile strength ( ft) of the concrete due to the denser microstructures of AAMs than OPC pastes. This improved characteristic was helpful in enhancing the bond performance of FRP bars, especially the slope of bond-slip curves in the ascending section (i.e., bond stiffness). Approximately three times enhancement in terms of the initial bond rigidity was achieved with SWSSAAC compared to SWSSC at the same concrete strength. Furthermore, compared with the BFRP and GFRP bars, the specimens reinforced with the CFRP bars experienced higher bond strength and bond rigidity due to their relatively high tensile strength and elastic modulus. Additionally, significant improvements in initial bond stiffness and bond strength were also observed as the alkaline contents (i.e., concrete strength) of the SWSSAAC were aggrandized, demonstrating the integration of the FRP bars and SWSSAAC is achievable, which contributes to an innovative channel for the development of SWSSC pavements or structures.

scholarly journals Effect of the degree of corrosion on bond performance of Cement Polymer Composite (CPC) Coated steel rebars

2018 ◽  
Vol 199 ◽  
pp. 04010
Author(s):  
Deepak K. Kamde ◽  
Radhakrishna G. Pillai
Keyword(s):  
Bond Strength ◽  
Polymer Composite ◽  
Continuous Monitoring ◽  
Coated Steel ◽  
Bond Performance ◽  
Pull Out ◽  
Curing Period ◽  
Uncoated Steel ◽  
Concrete Coating ◽  
Steel Rebars

Currently, large infrastructures (bridges, highways, etc.) are designed for more than 100 years. To achieve long service life, coated rebars (mostly, cement polymer composite (CPC) coated rebars) are being used to enhance the corrosion resistance. However, inadequately coated rebars can lead to premature corrosion. This can also affect the bond between the rebar and the concrete. To assess the effect of CPC coating on bond strength, pull-out specimens of (150×150×100) mm with 12 mm diameter rebar with 100 mm embedded length were cast and tested. For this, three replica specimens with two types of reinforcement namely, i) Uncoated steel ii) CPC coated steel were cast. To induce corrosion, additional five specimens with CPC coated steel rebars were cast with premixed chloride and cured for 28 days. During the curing period, continuous monitoring of corrosion potential and rate was done and degree of corrosion was assessed. The effect of degree of corrosion on bond of steel-concrete-coating interface was quantified. The CPC coated rebars without corrosion exhibited 10% bond reduction. CPC coated rebars with corrosion exhibited 30-70% reduction in bond strength. Also, the corrosion is found to adversely influence the stiffness of the bond.

Evaluation on the Addition of Inhibitor and Surface Treatment to Corrosion Behavior of the Reinforced Steel Bar Embedded in Mortar Specimen

2017 ◽  
Vol 744 ◽  
pp. 114-120
Author(s):  
Kyung Man Moon ◽  
Sung Yul Lee ◽  
Jae Hyun Jeong ◽  
Myeong Hoon Lee
Keyword(s):  
Current Density ◽  
Test Specimen ◽  
Corrosion Current Density ◽  
Corrosion Current ◽  
Corrosion Properties ◽  
Mortar Specimen ◽  
Steel Bar ◽  
Steel Bars ◽  
Reinforced Steel ◽  
One Year

In this study, seven types of mortar test specimens were manufactured with parameters, that is, the surface of the reinforced steel bar was treated with hot dip galvanizing (Zn) and the surface of the test specimen was coated with underwater paint, and four types of inhibitors (DAW, MCI, DCI, and Silcon) were added in mortars respectively. And, the seven types of mortar test specimens were immersed in seawater for 4 years. The corrosion properties of the reinforced steel bars embedded in mortar test specimens were investigated using electrochemical methods. The corrosion potentials of the test specimens with painting on the surface of the specimen and Zn coating on the surface of the steel bar exhibited the noblest and lowest values respectively after one year, however, after 4 years, the specimens of underwater painting and of addition of Silcon inhibitor indicated the noblest and lowest values of corrosion potentials respectively. Furthermore, the painting specimen exhibited the smallest values of corrosion probability as welll as of the corrosion current density, while, addition of MCI inhibitor showed the highest values of both corrosion probability and corrosion current density. Moreover, the painting specimen showed the smallest value of neutralization degree among all the specimens, and the largest value of neutralization degree was observed at the specimen of natural condition (no adding of inhibitor, no painting and no Zn coating). As a result, it is considered that the addition of inhibitors, coating with hot dip galvanizing (Zn), and painting on the surface have the effects not only to inhibit the neutralization degree but also to increase the corrosion resistance of the embedded steel bar.

scholarly journals Experimental study on the effect of concrete strength and corrosion level on bond between steel bar and concrete

2021 ◽  
Vol 72 (4) ◽  
pp. 498-509
Author(s):  
Vuong Doan Dinh Thien ◽  
Hung Nguyen Thanh ◽  
Hung Nguyen Dinh
Keyword(s):  
Compressive Strength ◽  
Bond Strength ◽  
Concrete Strength ◽  
Concrete Block ◽  
Bond Stress ◽  
Concrete Compressive Strength ◽  
Pull Out ◽  
Steel Bar ◽  
Stress Degradation ◽  
Slip Displacement

Corrosion of the steel reinforcement bars reduces the area of the steel bar and the bond stress between the steel bars and around concrete that decreases the capacity of concrete structures. In this study, the bond stress between steel bar with a diameter of 12mm and concrete was examined with the effect of different corrosion levels and different concrete grades. A steel bar was inserted in a concrete block with a size of 20×20×20cm. The compressive strength of concrete was 25.6MPa, 35.1MPa, and 44.1MPa. These specimens were soaked into solution NaCl 3.5% to accelerate the corrosion process with different corrosion levels in the length of 60mm. The pull-out test was conducted. Results showed that the bond strength of the corroded steel bar was higher than that predicted from CEB-FIP. Slip displacement and the range of slip displacement at the bond strength were reduced when the concrete compressive strength was increased. The rate of bond stress degradation occurred faster with the increment of the corrosion level when the concrete compressive strength was increased.

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