scholarly journals DETERMINATION OF BOND PERFORMANCE CHARACTERISTICS OF STEEL REINFORCEMENT PULL-OUT AND SPLITTING FAILURE IN REINFORCED CONCRETE MEMBERS

2020 ◽  
Vol 5 (4) ◽  
Author(s):  
OVERO KENNETH EJUKONEMU
Keyword(s):  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Performance Characteristics ◽  
Bond Performance ◽  
Concrete Members ◽  
Pull Out ◽  
Splitting Failure

scholarly journals The Effect of Freeze-Thaw Damage on Corrosion in Reinforced Concrete

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xiao-Chun Lu ◽  
Bin Guan ◽  
Bo-Fu Chen ◽  
Xin Zhang ◽  
Bo-bo Xiong
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Sem Analysis ◽  
Steel Reinforcement ◽  
Reinforcement Corrosion ◽  
Freeze Thaw ◽  
Pull Out ◽  
Thaw Cycle ◽  
Corrosion Reaction ◽  
Freeze Thaw Cycle

The existing studies of the corrosion of reinforced concrete have mainly focused on the interface area and chemical ion erosion, ignoring the specific service environment of the reinforced concrete. In this study, the effect of freeze-thaw damage was investigated via corrosion experiments under different freeze-thaw cycle conditions. Steel reinforcement corrosion mass, ultimate pull-out force, corrosion rate, and bond slippage were chosen as characteristic parameters in the experiments, and scanning electron microscopy (SEM) analysis was used to explain the mechanism of action of freeze-thaw damage on corrosion. The results showed that, under identical corrosion conditions, the mass of steel reinforcement corrosion and corrosion rate increased by 39.6% and 39.7% when comparing 200 freeze-thaw cycles to 0 cycles, respectively. The ultimate pull-out force and bond slippage after 200 freeze-thaw cycles decreased by 73% and 31%, respectively, compared with 0 freeze-thaw cycles. In addition, SEM analysis indicated that microstructure damage caused by freeze-thaw cycles accelerated the corrosion reaction and decreased cementitious properties, leading to decreasing ultimate pull-out force and bond slippage. The effect of freeze-thaw cycles and steel reinforcement corrosion on the macro mechanical properties of concrete is not a simple superposition.

Determination of Performance Status for RC Members

2013 ◽  
Vol 438-439 ◽  
pp. 488-490 ◽  
Author(s):  
Hai Tao Wan ◽  
Li Li Zhou
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Behavior ◽  
Performance Status ◽  
Loading Process ◽  
Concrete Members ◽  
Deformation Properties

The yield status and ultimate status are two very important performance statuses during the loading process of reinforced concrete (RC) members. The yield status and ultimate status can be determined by inspecting the deformation properties of reinforced concrete members. This paper describes four methods to determine the yield status of reinforced concrete members, and three methods to determine the ultimate status of reinforced concrete members. Through these methods, we can understand the mechanical behavior of reinforced concrete members.

scholarly journals Structural effects of steel reinforcement corrosion on statically indeterminate reinforced concrete members

2016 ◽  
Vol 49 (12) ◽  
pp. 4959-4973 ◽  
Author(s):  
Ignasi Fernandez ◽  
Manuel F. Herrador ◽  
Antonio R. Marí ◽  
Jesús Miguel Bairán
Keyword(s):  
Reinforced Concrete ◽  
Steel Reinforcement ◽  
Reinforcement Corrosion ◽  
Structural Effects ◽  
Concrete Members

scholarly journals ASSESSMENT OF THE DEPTH AND RATE OF CORROSION IN STEEL REINFORCEMENT OF REINFORCED CONCRETE CULVERTS

2020 ◽  
Author(s):  
Alexandr Vasiliev ◽  
Svetlana Daškevič
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Damage ◽  
Steel Reinforcement ◽  
Operating Conditions ◽  
Protective Properties ◽  
Open Atmosphere ◽  
Concrete Elements ◽  
Corrosion State

Based on the results of many research years on concrete carbonisation: both immediately after manufacture (using heat-moisture treatment) and in reinforced concrete elements operated for the periods of various length (in an open atmosphere); the effect of carbonisation on the change in the protective properties of concrete in relation to steel reinforcement; for determination of the dependence of the corrosion state of steel reinforcement on the degree of concrete carbonisation in the area of steel reinforcement; the obtained regression dependences of the change (by time in the cross section) of the degree of concrete carbonisation of various classes in strength, – the analysis of the time of the onset of the boundary values of the degrees of concrete carbonisation (strength classes C12/15–C30/37) for the operating conditions of the open atmosphere was performed. Based on it, the regression dependences of the time variation of the depth of corrosion damage of steel reinforcement were construed (for fixed thicknesses of the concrete protective layer). The obtained nature of dependences made it possible to offer, in a general form, the regression dependences of the depth of corrosion damage and corrosion rate of steel reinforcement for concretes (strength classes C12/15–C30/37) for operating conditions in open atmosphere.

scholarly journals Beam Bond Tests of GFRP and Steel Reinforcement to Concrete

2018 ◽  
Vol 64 (4) ◽  
pp. 243-256
Author(s):  
D. Szczech ◽  
R. Kotynia
Keyword(s):  
Reinforced Concrete ◽  
Surface Preparation ◽  
Steel Reinforcement ◽  
Experimental Program ◽  
Bond Behaviour ◽  
Gfrp Bars ◽  
Concrete Members ◽  
Glass Fiber Reinforced ◽  
Steel Bars ◽  
Frp Bars

AbstractThe paper presents research program of bond between glass fiber reinforced polymer bars and concrete in reference to the steel bars. Bond between the reinforcement and concrete is a crucial parameter governing a behaviour of reinforced concrete members and transferring of the internal forces from concrete to the reinforcement. The use of FRP bars as an equivalent reinforcement to steel in concrete structures has increased in recent years. The FRP bars are very different from steel, mainly due to much lower elasticity modulus and their anisotropic structure. Good performance of FRP reinforced concrete requires sufficient interfacial bond between bars and concrete. However, there are no specific standards referring to the surface preparation of these bars, that leads to variable bond behaviour of the composite reinforcement to the concrete. The objective of the study was to investigate the influence of variable parameters on the bond behaviour to concrete. The experimental program consisted of eighteen beam bond specimens varying in: bar diameter (12mm, 16mm, 18mm) and type of reinforcement (GFRP sand – coated and steel bars). Although the GFRP bars indicated good bond behaviour to concrete, the average bond strength was slightly lower than that of steel reinforcement of 16mm and 18 mm, while it was higher for the GFRP bars of 12mm diameter.

Determination of crack width in reinforced-concrete members of hydraulic structures

1975 ◽  
Vol 9 (3) ◽  
pp. 220-225
Author(s):  
I. B. Sokolov ◽  
V. N. Gubar ◽  
S. F. Zhivetin ◽  
T. I. Sergeeva
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Hydraulic Structures ◽  
Concrete Members

scholarly journals EFFECT OF BOND PERFORMANCE ON SHEAR TRANSFER MECHANISM IN REINFORCED CONCRETE MEMBERS

2003 ◽  
Vol 68 (564) ◽  
pp. 103-108 ◽  
Author(s):  
Seijiro IIDA ◽  
Masayuki HAMAHARA ◽  
Hiromitsu SUETSUGU ◽  
Tsuyoshi FUKUI
Keyword(s):  
Reinforced Concrete ◽  
Transfer Mechanism ◽  
Shear Transfer ◽  
Bond Performance ◽  
Concrete Members

scholarly journals Phosphate coatings as a way to protect steel reinforcement from corrosion

2019 ◽  
Vol 298 ◽  
pp. 00126 ◽  
Author(s):  
Sergey Fedosov ◽  
Varvara Roumyantseva ◽  
Viktoriya Konovalova
Keyword(s):  
Reinforced Concrete ◽  
Building Materials ◽  
Chloride Ions ◽  
Steel Reinforcement ◽  
Protective Properties ◽  
Phosphate Coatings ◽  
Mass Transfer Mechanism ◽  
Reinforced Steel ◽  
Kinetics Of

Phosphate coatings are successfully applied as a method of protecting steel products and structures from corrosion. Phosphate coatings mechanically prevent the entry of aggressive particles, such as chloride ions, to the surface of steel reinforcement. The parameters of corrosion rate of reinforcing steel in aggressive environment are determined by graphical method. The analysis of corrosion diagrams allows us to judge the effect of protective phosphate coatings on the kinetics of the corrosion process of steel reinforcement in environments of varying degrees of aggressiveness. The tests of the protective properties of phosphate coatings by contact corrosion method show that films with a finer crystal structure, as in modified phosphate coatings, are more resistant to anodic dissolution of steel. In parallel to determination of iron ions content in solutions the potential of steel reinforcement samples was measured. In samples protected by phosphate films, the potential change is not as sharp as in samples without coating, and the “dilution” of steel is slower. The study of anodic behavior of steel reinforcement of reinforced concrete, experimental study of the mass transfer mechanism of electrolyte supply to the surface of reinforced steel allow to develop practical recommendations to improve corrosion resistance and ensure the durability of reinforced concrete building materials.

scholarly journals Structural Analysis and Design of Reinforced Concrete Bridge Corbels

2020 ◽  
Vol 10 (19) ◽  
pp. 6727
Author(s):  
Sara Cattaneo ◽  
Pietro Crespi ◽  
Luigi Biolzi
Keyword(s):  
Reinforced Concrete ◽  
Mechanical Response ◽  
Bending Moment ◽  
Simplified Approach ◽  
Analysis And Design ◽  
Strut And Tie ◽  
Concrete Members ◽  
Pull Out ◽  
Safety Barrier ◽  
Strut And Tie Model

Post-installed systems for the anchorage of safety barriers to bridge corbels are widely used today thanks to their flexibility and easiness of installation. Because of commonly found in situ boundary constraints, however, the design requirements for post-installed fasteners and rebars are frequently not satisfied or only partially satisfied. This paper assesses the mechanical response of a corbel where an innovative solution concerning the placement of post-installed reinforcement in reinforced concrete members was suggested. With reference to the refurbishment of bridge curbs, which usually requires concrete removal in the damaged top layers, the proposed method was based on the introduction of additional U-shaped post-installed rebars connecting the existing portion of the corbel to the newly cast top layer, in order to allow the transfer of the tension pull-out force exerted by the posts restraining the safety barrier. The layout investigated in this paper consisted of three anchors connecting the baseplate of the post supporting the safety barrier to the corbel (a layout commonly found in Italy). These anchors transfer the external actions (bending moment and shear) to the corbel thanks to the formation of a strut-and-tie system where the U-shaped rebars and the existing reinforcement play a crucial role. A strut-and-tie model of the corbel was presented to allow the use of a simplified approach to assess the safety of the corbel. The tests on real-scale specimens were also modeled numerically and additional models were considered to evaluate the effect of characteristics parameters (i.e., size of the corbel, existing shear reinforcement, etc.) on the overall response of the corbel.

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