scholarly journals Bond Deterioration of Corroded-Damaged Reinforced Concrete Structures Exposed to Severe Aggressive Marine Environment

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Cecielle N. Dacuan ◽  
Virgilio Y. Abellana
Keyword(s):  
Reinforced Concrete ◽  
Bond Strength ◽  
Crack Width ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Minimal Amount ◽  
Reinforced Concrete Structures ◽  
Exponential Relationship ◽  
Cross Sectional ◽  
Different Diameters

Cracks lead to a reduction of the bond between concrete and reinforcing steel rebars. A considerable decrease in the bond strength is more dangerous to a structural element’s safety than the loss of the cross-sectional steel reinforcement area. The purpose of this study is to evaluate the bond strength of corroded-damaged structures exposed to severely aggressive marine environments. Eighteen (18) cube specimens with dimensions of 200   mm   x   200   mm were cast. They were reinforced with three (3) different diameters of deformed steel and were grouped as unconfined and confined. The specimen was accelerated under a simulated corrosive environment. The experiment results reveal that the bond strength of concrete and steel reinforcement is susceptible to corrosion levels. The degree of corrosion significantly affects the bond strength of concrete and steel. The bond strength and the average crack width have a strong correlation; a minimal amount of corrosion with a minimum crack width of 0.03 mm after cracking reduces the bond strength to an unacceptable level. Stirrups confinement has a significant influence on the bond strength; it provides an excellent means to counteract bond loss. The loss of bond directly affects the serviceability and ultimate strength of reinforced concrete structures. There is an exponential relationship between cement and steel reinforcement’s bond strength with the serviceability and residual strength of reinforced concrete structures.

scholarly journals COMBINED EFFECT OF CARBONATION AND CHLORIDE AGGRESSION: DEG-RADATION OF REINFORCED CONCRETE STRUCTURES

2018 ◽  
Author(s):  
L.V. KIM ◽  
E.E. SHALYI ◽  
S.N. LEONOVICH ◽  
N.A. BUDREVICH
Keyword(s):  
Reinforced Concrete ◽  
Ph Value ◽  
Concrete Structures ◽  
Chloride Concentration ◽  
Protective Layer ◽  
Sharp Decrease ◽  
Threshold Concentration ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Cross Sectional

Corrosion reinforcement marine hydraulic structures due to chloride aggression and carbonization of concrete leads to a sharp decrease in the safety of the structure. The steel reinforcement will be subjected to a so-called depassivation process, once the chloride concentration on surface exceeds a certain threshold concentration, or the pH value in the protective layer of concrete decreases to a threshold value due to carbonation. Electrochemical reactions begin to occur with the formation of corrosion products with the penetration of oxygen on the steel reinforcement surface. This leads to cracking of the protective layer of concrete. It should also be taken into account that, due to corrosion mechanisms, the cross-sectional area of the reinforcement also decreases. The article suggests a method for predicting the complex degradation of reinforced concrete structures, taking into account various mechanisms of corrosion wear, which will allow developing effective ways to improve the durability and maintainability of structures operated in the marine environment.

scholarly journals Experimental study of the influence of crack width due to corrosion behaviour using different measurement methods and different exposures

2019 ◽  
Vol 289 ◽  
pp. 08005
Author(s):  
Martin Schneider ◽  
Georg Gardener
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Corrosion Behaviour ◽  
Concrete Strength ◽  
Concrete Structures ◽  
Chloride Ions ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Surface Corrosion ◽  
Potential Mapping

Corrosion of reinforcing steel has a great influence in reducing the lifetime of concrete structures; Carbonation of the concrete pore solution causes surface corrosion on the steel and diffusion of chloride ions through the capillary system of the concrete cover causes pitting corrosion on the steel surface. Corrosion of metals is highly dependent on the environmental conditions. Exposure to chloride ions can be critical to the service life of reinforced concrete structures. The durability of reinforced concrete structures exposed to deicing salt or marine environments can be affected by impact of chloride ions. Detection methods for the rate of corrosion of non-destructive and destructive procedures were analysed. The potential mapping applied on the concrete surface was discussed as a standard method for corrosion detection and will be explained in detail including the application boundaries of the method. It is assumed that the corrosion behaviour of reinforcing steel depends on crack widths. To analyse that, 8 coated and 8 uncoated test samples with different concrete strength classes were used. The concrete objects were exposed to a 3% sodium chloride solution. The corrosion behaviour of reinforcing steel is analysed by using potential mapping with different reference electrodes (Ag/AgCl and Cu/CuSO4). The results show a significant correlation between crack size and protection system on the surface. The maximum crack width with a low indication of corrosion was found to be 0.1 mm.

DEVELOPMENT OF EMBEDDED MINI-SENSOR FOR DIAGNOSIS OF CORROSION OF STEEL REINFORCEMENT IN CONCRETE NONDESTRUCTIVELY

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Mohamed A. Ismail ◽  
Han-Seung Lee ◽  
Mohd Warid Hussin
Keyword(s):  
Reinforced Concrete ◽  
Polarization Resistance ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Structures ◽  
Chloride Ingress ◽  
Reinforcement Corrosion ◽  
Maintenance And Rehabilitation ◽  
Corrosion Of Steel ◽  
Non Destructive

Corrosion of steel reinforcement embedded in concrete is one of the main causes of degradation of reinforced concrete structures. Degradation occurs in reinforced concrete structures from corrosion caused by the Chloride ingress into concrete. That degradation has a severe impact on the structure in terms of maintenance and rehabilitation costs. Therefore, early detection of reinforcement corrosion is important for efficient maintenance, repair and planning. Meanwhile, the evaluation of the corrosion of reinforcement by non-destructive measurements have been used a lot. In particular CM-II (corrosion meter) is used to measure the polarization resistance, but has some disadvantages. Embedded mini-sensor has been developed in order to overcome these disadvantages. In this study, measurement of corrosion by using the mini-sensor is compared with the measured results by CM-II to verify the validity of the newly developed mini senor. Results show that there are agreement in trends of the parameters measured and as such the developed mini sensor has a promising start to be used.

scholarly journals THE PROPERTIES OF PITTING CORROSION OF STEEL REINFORCEMENT OF REINFORCED CONCRETE BEAMS

2017 ◽  
Vol 2 (3) ◽  
pp. 32-36
Author(s):  
Дронов ◽  
Andrey Dronov
Keyword(s):  
Reinforced Concrete ◽  
Pitting Corrosion ◽  
Concrete Beams ◽  
Concrete Structures ◽  
Steel Reinforcement ◽  
Reinforced Concrete Beams ◽  
Reinforced Concrete Structures ◽  
Damage Distribution ◽  
Chloride Environment ◽  
Corrosion Of Steel

Two types of steel reinforcement depassivation process: carbonation of concrete and chloride penetration are considered in the article. The comparison between the corrosion due to carbonation of concrete and the chloride-induced corrosion was carried out. It was found out, that chlorides induced corrosion is potentially more dangerous than that resulting from carbonation. Method of durable tests of reinforced concrete structures under the action of the gravitational load and the corrosive chloride environment is described in the article. The results of experimental research on reinforced concrete structures with corrosive damages to steel reinforcement are given in the article. The properties of corrosion cracking in the case of the pitting corrosion were determined. The character of corrosive damage distribution along the reinforcement bars and its effect on the strength of reinforced concrete beams were determined.

scholarly journals Volumetric Deformations and Crack Control in Reinforced Concrete Structures

2021 ◽  
Author(s):  
Mahmut Acarcan
Keyword(s):  
Reinforced Concrete ◽  
Crack Width ◽  
Structural Integrity ◽  
Concrete Structures ◽  
Prediction Equation ◽  
Reinforcement Ratio ◽  
Strain History ◽  
Reinforced Concrete Structures ◽  
Limited Information ◽  
Reinforcement Design

Restraint temperature and shrinkage strains are one of the major reasons for cracking of reinforced concrete. Cracking of concrete reduces structural integrity, initiates or accelerates deterioration mechanisms, causes serviceability problems and may raise aesthetical concerns. Particularly for liquid retaining structures, cracks are vital for structural functionality. Measures must be take to prevent or control crack. In most cases, it may not be feasible to prevent crack formation, but crack width can be controlled by providing sufficient amount of reinforcement. Design guides provide limited information on adequate reinforcement design for temperature and shrinkage cracks in reinforced concrete structures. The Finite Element Method(FEM) was used in order to investigate the crack risk, magnitude of crack width, and adequate reinforcement ratio for controlling cracks within the design specifications. In order to find the thermal and shrinkage strains effect during early ages, computer simulations was performed for hardening concrete. Using the computer program ABAQUS/6.4, incremental numerical analysis technique was implemented that provided realistic simulation of stress/strain history. Considering an appropriate value for thermal and shrinkage strains, a parametric study was carried out to estimate the reinforcement ratio for fixed base walls. The crack width was estimated based on the calculated steel stress and the ACI 318-02 crack prediction equation. With consideration of ACI 350-01 specification for allowable crack width, the required amount of reinforcement ratio for various wall dimensions was recommended.

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