Accelerated aging tests for evaluations of durability performance of FRP reinforcing bars for concrete structures

2007 ◽  
Vol 78 (1) ◽  
pp. 101-111 ◽  
Author(s):  
Yi Chen ◽  
Julio F. Davalos ◽  
Indrajit Ray ◽  
Hyeong-Yeol Kim
Keyword(s):  
Concrete Structures ◽  
Accelerated Aging ◽  
Reinforcing Bars ◽  
Durability Performance

scholarly journals Comparison of the stress-strain state of the reinforced concrete structure under various mathematical models of concrete

2018 ◽  
Vol 251 ◽  
pp. 04032
Author(s):  
Dmitriy Sidorov ◽  
Vladimir Dorozhinskiy
Keyword(s):  
Reinforced Concrete ◽  
Mathematical Models ◽  
Strain State ◽  
Concrete Structures ◽  
Seismic Action ◽  
Reinforced Concrete Structure ◽  
Reinforcing Bars ◽  
Plastic Deformations ◽  
Regulatory Documents ◽  
Structural Engineer

Nowadays, reinforced concrete structures are most often used as load-bearing elements of buildings and structures. In the case of alternating loads such as seismic action, there is accumulation of residual plastic deformations in the concrete structures, which leads to a significant complication in the calculation of structures by “standard” methods. For such problems, it is advisable to use computational complexes in which mathematical models of structural materials are implemented, which allow to describe the work of concrete and reinforcing bars for various types of impacts more properly. However, when applying such methods, the results obtained should not contradict the requirements of the existing regulatory documents, which, in the first place, the structural engineer should be guided by. Before solving more complex problems, the applied methods should be verified and analyzed for fairly simple structures and types of loads.

scholarly journals Bearing capacity of RC beams reinforced with high strength rebars and steel plate

2018 ◽  
Vol 230 ◽  
pp. 02003 ◽  
Author(s):  
Taras Bobalo ◽  
Yaroslav Blikharskyy ◽  
Rostyslav Vashkevich ◽  
Myhailo Volynets
Keyword(s):  
Reinforced Concrete ◽  
Bearing Capacity ◽  
Steel Plate ◽  
Concrete Structures ◽  
High Strength ◽  
Strength Properties ◽  
Rc Beams ◽  
Reinforcing Bars ◽  
External Reinforcement ◽  
Effective Use

Nowadays, reducing the material content of not only buildings and structures in general, but also individual constructions is a topical task that can be realized through the use of high-strength concrete and reinforcement, as well as with the use of external reinforcement. The concentrated location of sheet reinforcement on the external the most tense facets of steel and concrete structures increases the operating height of the cross-section, makes it possible to more effectively use the strength properties of steel in comparison with conventional reinforced concrete, and with the same bearing capacity to economize on expenses. Composite and monolithic reinforced concrete structures with external reinforcement are used in various construction sectors around the world. This contributed to the expansion of the use of reinforced concrete for special buildings of power-engineering and hydrotechnical construction. The technical nd econom efficiency, as well as the possibility of using external rebar as formwork for monolithic concrete construction, have been proved. Therefore, there is a need for the study of structures with combined reinforcement, in which high rigidity of steel and concrete structures is combined with an effective use of high-strength reinforcing bars (rebar) without prior tension

Effect of Chloride-Induced Steel Corrosion on Working Life of Concrete Structures

2018 ◽  
Vol 272 ◽  
pp. 226-231 ◽  
Author(s):  
Ivan Hollý ◽  
Juraj Bilčík
Keyword(s):  
Pore Solution ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Radial Pressure ◽  
Concrete Cover ◽  
Transport Infrastructure ◽  
Reinforcing Bars ◽  
Volume Increase ◽  
Volumetric Expansion ◽  
High Alkalinity

The reinforcing steel embedded in concrete is generally protected against corrosion by the high alkalinity (pH = 12.5 to 13.5) of the concrete pore solution. The structural degradation of concrete structures due to reinforcement’s corrosion has an impact on the safety, serviceability and durability of the structure. The corrosion of reinforcements in the construction of a transport infrastructure (especially bridges), parking areas, etc., is primarily initiated by chlorides from de-icing salts. When corrosion is initiated, active corrosion results in a volumetric expansion of the corrosion products around the reinforcing bars against the surrounding concrete. Reinforcement corrosion causes a volume increase due to the oxidation of metallic iron, which is mainly responsible for exerting the expansive radial pressure at the steel–concrete interface and development of hoop tensile stresses in the surrounding concrete. When this tensile stress exceeds the tensile strength of the concrete, cracks are generated. Higher corrosion rates can lead to the cracking and spalling of the concrete cover. Continued corrosion of reinforcement causes a reduction of total loss of bond between concrete and reinforcement.

Chloride Ion Penetrability of HPFRCC after Loading

2014 ◽  
Vol 507 ◽  
pp. 242-244
Author(s):  
Kyung Joon Shin
Keyword(s):  
Crack Width ◽  
High Performance ◽  
Concrete Structures ◽  
Chloride Ion ◽  
Cementitious Composite ◽  
Fiber Reinforced ◽  
High Performance Fiber ◽  
Inherent Problem ◽  
Durability Performance

Cracking is one of the most important factors in the serviceability as well as durability performance of concrete structures. Recently, it was recognized that a high performance fiber-reinforced cementitious composite (HPFRCC) provides a possible solution to this inherent problem of cracking by smearing one or several dominant cracks into many distributed microcracks. The purpose of the present study is to explore the ductility characteristics of HPFRCC. The permeability of HPFRCC after subjected to different load levels were measured to identify the effect of reduced cracking among the mixtures. It was confined that the permeability of proposed mixtures was lower than that without microfibers. This means that the proposed materials can reduce the crack width greatly at the same applied loads

Numerical Interpretation of Bond Between Steel and Concrete in Presence of Corrosion and Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 349-352 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Stress Transfer ◽  
Experimental Tests ◽  
Radial Pressure ◽  
Mechanical Action ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
Bond Slip

Bond between steel and concrete in reinforced concrete structures plays a fundamental role. The stress transfer mechanism depends on the condition of the contact surface between the two materials, the mechanical characteristics of concrete near the rebar and on the available level of confinement. Corrosion of reinforcing bars in concrete structures modifies those three factors. Because of corrosion, on the rebar surface a granular oxide layer is present and with its expansion it generates a significant radial pressure; consequently tensile stresses grow till cracking of the concrete cover with a subsequent reduction of the confinement effect. Moreover the presence of a mechanical action modifies the resisting mechanism producing an increasing damage. In this study, a model is presented for the numerical simulation of experimental tests on r.c. ties subjected to mechanical action; furthermore some considerations on reinforced concrete ties subjected also to corrosion effect are reported. From those analyses it is possible to estimate a modified bond-slip law between the reinforcing bars and the concrete, in order to take into account the level of damage.

Experimental Evaluation of Corrosion Effect on Bond Between Steel and Concrete in Presence of Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 345-348 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Load ◽  
Crack Opening ◽  
Concrete Structures ◽  
Electrochemical Corrosion ◽  
Reinforced Concrete Structures ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
In Series ◽  
Ultimate Condition

Corrosion modifies the steel-concrete interface in reinforced concrete structures. The efficiency of the connection between the two materials is reduced and the structural behavior both in service and in ultimate condition is affected. Moreover in structures subjected to cyclic load, a simultaneous mechanical deterioration due to the load is present. In this work an experimental analysis on reinforced concrete structures under both cyclic load and corrosion of reinforcing bars is presented. Three couples of reinforced concrete ties are connected in series and subjected to the same stress variation in order to produce the cracking conditions and to activate the bond mechanism. However, while one of the two reinforced concrete ties is only subjected to cyclic load, the second one is also corroded using an accelerated electrochemical corrosion process. The simultaneous effect of the cyclic load and corrosion is evaluated monitoring the crack opening on the structures during the test and by means of visual inspection of the sample. The test results show the correlation between the mechanism of bond and the average level of stresses for an amplified stress range.

scholarly journals Modelling Dowel Action of Discrete Reinforcing Bars in Cracked Concrete Structures

2010 ◽  
Author(s):  
A. K. H. Kwan ◽  
P. L. Ng ◽  
J. Y. K. Lam ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
...  
Keyword(s):  
Concrete Structures ◽  
Reinforcing Bars ◽  
Cracked Concrete ◽  
Dowel Action

Performance Based Specifications for Durability of Mass Concrete Blocks Subjected to Harsh Arabian Gulf Marine Environment

2016 ◽  
Vol 711 ◽  
pp. 444-452
Author(s):  
K. Rahman Muhammad ◽  
Al Omran Zaki ◽  
Ibrahim Mohammed ◽  
Al Nahdi Fahad ◽  
S. Barry Mohammed
Keyword(s):  
Service Life ◽  
Arabian Gulf ◽  
Concrete Structures ◽  
Experimental Investigations ◽  
Eastern Region ◽  
Mass Concrete ◽  
Reinforcing Steel ◽  
Concrete Blocks ◽  
Durability Performance

Concrete structures in the Eastern region of Saudi Arabia are exposed to the harsh Arabian Gulf environment, and they suffer from deterioration due to accelerated corrosion of the reinforcing steel resulting in reduced service life. The service life of reinforced concrete structures in this environment is strongly affected by the quality of concrete. The resistances of concrete to chloride penetration, the chloride threshold for corrosion initiation and corrosion rate of the reinforcing steel are critical in ensuring long-term durability of concrete structures. In order to ensure that the concrete functions in the harsh environment for which it is expected to meet the service life requirement, the concrete must be designed for durability performance. A prescriptive concrete specification emphasizing on limits on mix parameters is generally ineffective for durability issues. A performance based specification based on concrete quality represented by durability indices and compliance criteria measured on cast-in-place concrete provides a framework for the contractor and ready-mix concrete supplier to produce a structure meeting the stipulated service life by the client. This paper presents the results of experimental investigations conducted for mass-concrete blocks used in the quay walls off the coastline on a reclaimed land. For long-term durability, a concrete mix in which 50% and 70% of cement was replaced by ground blast furnace slag was used to cater for the durability performance requirements.

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