Structural Materials. Steel Bar Corrosion of Concrete Structures Affected by Combined Deteriorating Causes.

1996 ◽  
Vol 45 (9) ◽  
pp. 1048-1054
Author(s):  
Yukio KITAGO ◽  
Shigehiro KOBAYASHI ◽  
Yasutaka KIKUCHI ◽  
Toyoaki MIYAGAWA ◽  
Manabu FUJII
Keyword(s):  
Concrete Structures ◽  
Structural Materials ◽  
Steel Bar

scholarly journals Effects of Cyclic Freeze–Thaw on the Steel Bar Reinforced New-To-Old Concrete Interface

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1251
Author(s):  
Tao Luo ◽  
Chi Zhang ◽  
Xiangtian Xu ◽  
Yanjun Shen ◽  
Hailiang Jia ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Shear Strength ◽  
Concrete Structures ◽  
Freezing Temperature ◽  
Frost Damage ◽  
Freezing And Thawing ◽  
Shear Properties ◽  
Freeze Thaw ◽  
Steel Bar ◽  
Concrete Interface

Frost damage of concrete has significant effects on the safety and durability of concrete structures in cold regions, and the concrete structures after repair and reinforcement are still threatened by cyclic freezing and thawing. In this study, the new-to-old concrete interface was reinforced by steel bar. The shear strength of the new-to-old concrete interface was tested after the new-to-old combination was subjected to cyclic freeze–thaw. The effects of the diameter of the steel bar, the compressive strength of new concrete, the number of freeze–thaw cycles and the freezing temperatures on the shear properties of new-to-old concrete interface were studied. The results showed that, in a certain range, the shear strength of the interface was proportional to the diameter of the steel bar and the strength of the new concrete. Meanwhile, the shear strength of the reinforced interface decreased with the decreasing of the freezing temperature and the increasing of the number of freeze–thaw cycles.

scholarly journals Mechanical Properties of Steel-FRP Composite Bars under Tensile and Compressive Loading

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Zeyang Sun ◽  
Yu Tang ◽  
Yunbiao Luo ◽  
Gang Wu ◽  
Xiaoyuan He
Keyword(s):  
Failure Modes ◽  
Flexural Rigidity ◽  
Compressive Loading ◽  
Concrete Structures ◽  
Frp Composite ◽  
Steel Bar ◽  
Calculated Stress ◽  
Frp Bar ◽  
Large Length ◽  
Ordinary Steel

The factory-produced steel-fiber reinforced polymer composite bar (SFCB) is a new kind of reinforcement for concrete structures. The manufacturing technology of SFCB is presented based on a large number of handmade specimens. The calculated stress-strain curves of ordinary steel bar and SFCB under repeated tensile loading agree well with the corresponding experimental results. The energy-dissipation capacity and residual strain of both steel bar and SFCB were analyzed. Based on the good simulation results of ordinary steel bar and FRP bar under compressive loading, the compressive behavior of SFCB under monotonic loading was studied using the principle of equivalent flexural rigidity. There are three failure modes of SFCB under compressive loading: elastic buckling, postyield buckling, and no buckling (ultimate compressive strength is reached). The increase in the postyield stiffness of SFCB rsf can delay the postyield buckling of SFCB with a large length-to-diameter ratio, and an empirical equation for the relationship between the postbuckling stress and rsf is suggested, which can be used for the design of concrete structures reinforced by SFCB to consider the effect of reinforcement buckling.

scholarly journals Bond Performance of Carbon Fiber-Reinforced Polymer Bar with Dual Functions of Reinforcement and Cathodic Protection for Reinforced Concrete Structures

2020 ◽  
Vol 2020 ◽  
pp. 1-13 ◽  
Author(s):  
Yingwu Zhou ◽  
Lili Sui ◽  
Feng Xing ◽  
Xiaoxu Huang ◽  
Yaowei Zheng ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Cathodic Protection ◽  
Concrete Structures ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Reinforced Concrete Structures ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Steel Bar

The dual function of a carbon fiber-reinforced polymer (CFRP) bar working as reinforcement and impressed current cathodic protection (ICCP) anode for reinforced concrete structures has been proposed and researched in this paper. The ICCP tests with different current densities and polarization durations were first conducted for the concrete with high chloride content. After the ICCP application, pull out tests were then performed to investigate the bond behaviors of CFRP bars. Experimental results have shown the effectiveness of the new-type ICCP system with the CFRP bar as the anode on corrosion protection. The ICCP system provided electrons to the steel bar continuously and brought the potential of the steel bar down to the immunity region. Under the anodic polarization with a large current density of 100 mA/m2, the CFRP bar-concrete interface presented acidification and the chemical adhesion on the interface was decreased significantly. However, for cases in the experiment, the ICCP application had an insignificant influence on the ultimate bond strength.

scholarly journals Experimental Study on Anchorage Performance of Steel Bars with FRP Confined Rings

2018 ◽  
Vol 175 ◽  
pp. 01037
Author(s):  
Qiao Jin ◽  
Jinglong Li ◽  
Meng Gao ◽  
Xuebin Wen ◽  
Zeming Zhao
Keyword(s):  
Concrete Structures ◽  
Tensile Tests ◽  
Construction Process ◽  
Grouting Material ◽  
Steel Bar ◽  
Steel Bars ◽  
Local Destruction ◽  
Reliable Performance ◽  
Static Tensile ◽  
Restrained Ring

In order to study the performance of reinforcement anchorage connection with FRP restrained ring, static tensile tests were carried out on 66 specimens, The main parameters considered in the test such as the diameter of steel bars, the diameter and thickness of the restraint ring, the strength of concrete and the length of anchorage. The result shows that the anchorage performance of the steel bar can still be guaranteed even if the anchorage length reaches 0.8la, There is no slip and local destruction phenomenon between FRP restraint ring and internal grouting material and peripheral concrete. The study conclusions also indirectly prove that the proposed technique is a reinforcement connection method for fabricated concrete structures with many good performances including the reliable performance, simple construction process and good economic benefit, which is suitable for construction industrialization of prefabricated reinforced concrete structures..

Prediction of Crack Width of Chloride Contaminated Reinforced Concrete Structures

2006 ◽  
Vol 302-303 ◽  
pp. 610-617
Author(s):  
Jia Jin Zheng ◽  
Xin Zhu Zhou ◽  
Shi Lang Xu
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Corrosion Rate ◽  
Crack Width ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Cover Depth ◽  
Steel Bar ◽  
Bar Diameter ◽  
Chloride Contaminated

Crack width is a significant parameter for assessing service life of reinforced concrete structures in chloride-laden environments. Corrosion-induced concrete cracking is a predominant causal factor influencing premature degradation of reinforced concrete structures, incurring considerable costs for repairs and inconvenience to the public due to interruptions. This gives rise to the need for accurate prediction of crack width in order to achieve cost-effectiveness in maintaining serviceability of concrete structures. It is in this regard that the present paper attempts to develop a quasi-brittle mechanical model to predict crack width of chloride contaminated concrete structures. Assuming that cracks be smeared uniformly in all directions and concrete be a quasi-brittle material, the displacement and stress in a concrete cover, before and after surface cracking, were derived respectively in an analytical manner. Crack width, as a function of the cover depth, steel bar diameter, corrosion rate and time, was then determined. Finally, the analysis results were verified by comparing the solution with the experimental results. The effects of the cover depth, steel bar diameter and corrosion rate on the service life were discussed in detail.

Magnetoelastic Measurements of Steel Stress under Uniaxial Loading

2006 ◽  
Vol 321-323 ◽  
pp. 377-380 ◽  
Author(s):  
Hong C. Rhim ◽  
Bo Hwan Oh ◽  
Hyo Seon Park
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Uniaxial Loading ◽  
Magnetic Response ◽  
Reinforced Concrete Structures ◽  
Test Results ◽  
Traditional Technique ◽  
Steel Bar ◽  
Steel Bars ◽  
Different Diameters

An attempt has been made to measure existing steel stress using magnetoelasticity. A device has been developed and used for the measurement of magnetism in response to the deformation of a steel bar. The proposed technique can be used for the assessment of existing reinforced concrete structures by the measurements of steel stress embedded inside concrete. A traditional technique requires to break the existing steel bar to measure existing strain. However, the proposed technique is developed to measure the stress without damaging the steel bar. A successful application of magnetoelasticity depends on the establishment of relationship between elastic and magnetic response due to loading. To investigate the correlation between the two, steel bars are loaded in tension under uniaxial loading while the magnetic reading is recorded. Based on the test results, equations are suggested to predict stress for steel bars with different diameters.

Modified Steel Bar Model Incorporating Bond-Slip for Seismic Assessment of Concrete Structures

2012 ◽  
Vol 138 (11) ◽  
pp. 1342-1350 ◽  
Author(s):  
Franco Braga ◽  
Rosario Gigliotti ◽  
Michelangelo Laterza ◽  
Michele D’Amato ◽  
Sashi Kunnath
Keyword(s):  
Concrete Structures ◽  
Seismic Assessment ◽  
Bond Slip ◽  
Steel Bar

scholarly journals Effect of Fibers on the Bond Behavior of Deformed Steel Bar Embedded in Recycled Aggregate Concrete

2020 ◽  
Vol 39 (4) ◽  
pp. 846-858
Author(s):  
Rashid Hameed ◽  
Usman Akmal ◽  
Qasim S. Khan ◽  
Muhammad Ahsan Cheema ◽  
Muhammad Rizwan Riaz
Keyword(s):  
Compressive Strength ◽  
Concrete Structures ◽  
Steel Fibers ◽  
Recycled Aggregates ◽  
Polypropylene Fibers ◽  
Reinforcing Bars ◽  
Bond Behavior ◽  
Pull Out ◽  
Steel Bar ◽  
Natural Aggregates

A large volume of concrete debris is being produced in many countries on the globe due to the demolition of old concrete structures and testing of concrete specimens in laboratories. One of the ways to reuse concrete debris is to produce Recycled Aggregates (RA) and use them in new concrete. In recent years, Recycled Aggregates Concrete (RAC) has experienced increasing demand in various non-structural and structural applications. In reinforced concrete structures, one of the sources of brittle failure is sudden loss of bond between reinforcing bars and concrete in anchorage zones. Therefore, for the structural application of any new kind of concrete such as fiber reinforced RAC, knowledge of bond characteristics of reinforcing bars embedded in concrete becomes essential for determining the overall structural response under different modes of loading. In this regard, this study experimentally investigated the effect of fibers on the bond stress-slip behavior of deformed steel re-bar embedded in RAC. Concrete mixes having 0, 50 and 100% RAs were prepared with and without the addition of fibers. Two types of fibers were investigated in mono form: hooked-ends steel and polypropylene fibers. The dosage of steel and polypropylene fibers was kept 40 and 4.4 kg/m3, respectively. Axial compression and standard pull-out tests were performed. Test specimens for pull-out test were prepared using deformed steel re-bars of 19mm (#6) diameter. The results of strength tests confirmed that the compressive strength of concrete is decreased by replacing Natural Aggregates (NA) with RAs. For bond behavior of steel re-bar, the results of this study showed that replacement of 50% NA with RAs did not affect the bond response of steel bar, however, 100% replacement of NA with RAs showed detrimental effect on bond stress slip behavior. The results further showed that the addition of both types of fibers made it possible to recover the loss in compressive strength, bond strengths and bond toughness occurred because of replacing NA with RAs. In case of RA concrete mixes containing hooked-ends steel fibers, strength values were found even greater than the strength values of Natural Aggregates Concrete (NAC). From the results of this study, it was found that it is possible to design a structural concrete mix using 100% RAs and steel fibers at relatively low dosage of 40kg/m3.

The Construction Quality Control Measures of Reinforced Concrete Cover Research

2014 ◽  
Vol 599-601 ◽  
pp. 1094-1097
Author(s):  
Shao Jun Zhang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Protective Layer ◽  
Concrete Cover ◽  
Control Measures ◽  
Reinforced Concrete Structures ◽  
Molding Process ◽  
Steel Bar ◽  
Reinforced Concrete Member ◽  
Design Production

reinforced concrete structures reinforced protective layer deviation will directly affect the mechanical properties and durability of the reinforced concrete member, in relation to the structure of the use of safety and service life. The control to the protective layer of reinforced concrete structures include the following aspects: to do a good job of double sample, reinforced the blue prints.the design, production and installation of template engineering, reinforcing steel bar colligation molding process, placed, binding of fixed steel protective layer block and the requirements on the installation of the steel skeleton.

Sign in / Sign up

Export Citation Format

Share Document