scholarly journals Macrocell Corrosion And Its Countermeasure For Reinforced Concrete After Patch Repair

2020 ◽  
Vol 11 (6) ◽  
pp. 20061528-20061528
Author(s):  
Shinichi Miyazato
Keyword(s):  
Reinforced Concrete ◽  
Patch Repair ◽  
Macrocell Corrosion

Contribution of Sacrificial Anode in reinforced concrete patch repair: Results of numerical simulations

2018 ◽  
Vol 178 ◽  
pp. 405-417 ◽  
Author(s):  
Eric Lozinguez ◽  
Jean-François Barthélémy ◽  
Véronique Bouteiller ◽  
Tiffany Desbois
Keyword(s):  
Reinforced Concrete ◽  
Numerical Simulations ◽  
Patch Repair ◽  
Sacrificial Anode

Shear Failure of Patched Reinforced Concrete Beam without Web Reinforcements

2017 ◽  
Vol 737 ◽  
pp. 441-447 ◽  
Author(s):  
Stefanus Kristiawan ◽  
Agus Supriyadi ◽  
Senot Sangadji ◽  
Hapsara Brian Wicaksono
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beam ◽  
Shear Failure ◽  
Unsaturated Polyester ◽  
Reinforced Concrete Beam ◽  
Concrete Cover ◽  
Patch Repair ◽  
Rc Beam ◽  
Diagonal Crack ◽  
The Web

Degradation of reinforced concrete (RC) element could lead to a reduction of its strength and serviceability. The degradation may be identified in the form of spalling of concrete cover. For the case of RC beam, spalling of concrete cover could occur at the web of the shear span due to corrosion of the web reinfocements. The shear strength of the damaged-RC beam possibly will become less conservative compared to the corresponding flexural strength with a risk of brittle failure. Patch repair could be a choice to recover the size and strength of the damaged-RC beam. This research investigates the shear failure of patched RC beam without web reinforcements with a particular interest to compare the shear failure behaviour of patched RC beam and normal RC beam. The patch repair material used in this research was unsaturated polyester resin (UPR) mortar. The results indicate that the initial diagonal cracks leading to shear failure of patched RC beam occur at a lower level of loading. However, the patched RC beam could carry a greater load before the diagonal crack propagates in length and width causing the beam to fail in shear.

Effect of Anodic and Cathodic Chloride Contents on the Macrocell Corrosion and Polarization Behavior of Reinforcing Steel

2016 ◽  
Vol 22 ◽  
pp. 45-58 ◽  
Author(s):  
Zhong Lu Cao ◽  
Hao Yu Chen ◽  
Lian Yu Wei ◽  
Makoto Hibino
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Chloride Content ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Anodic Reaction ◽  
Polarization Behavior ◽  
Mixed Control ◽  
Cement Mortars ◽  
Macrocell Corrosion

The effect of anodic and cathodic chloride contents on the macrocell corrosion and polarization behavior of reinforcing steel embedded in cement mortars were investigated and clarified. The results indicated that the higher cathodic chloride content could accelerate the cathodic reaction of cathode and make the controlling mode of macrocell corrosion changed from cathodic control to mixed control or anodic control. The higher anodic chloride content could accelerate the anodic reaction of anode and make the macrocell corrosion more controlled by cathode. These results will provide a guide to inhibiting the macrocell corrosion of reinforcing steel in concrete, which are not only useful for engineers to design and construct the new marine reinforced concrete structures, but also are helpful for engineers to repair or rehabilitate the existing chloride contaminated reinforced concrete structures, in the condition of avoiding the adverse effect of macrocell corrosion induced by the non-uniform distribution of anodic and cathodic chloride.

scholarly journals Performance of Cement-Based Patch Repair Materials in Plain and Reinforced Concrete Members

2016 ◽  
Vol 13 (2) ◽  
pp. 160
Author(s):  
A.H. Al-Saidy
Keyword(s):  
Mechanical Properties ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Plain Concrete ◽  
Reinforced Concrete Beams ◽  
Patch Repair ◽  
Concrete Members ◽  
Repair Materials ◽  
Superior Mechanical Properties ◽  
The Cost

Structural elements such as beams, slabs, and columns may require strengthening or repair during their service life. Different repair materials (RMs) are available and it is usually difficult to choose the best ones, especially when considering the cost of such materials. This paper presents the results of an experimental investigation of patch RMs on plain concrete prisms as well as on reinforced concrete beams. Three cement-based RMs available in the market with different mechanical properties and an ordinary Portland cement (OPC) mix produced in the lab were used in the study. Damage was induced in prisms/beams and then repaired using different materials. The experimental work included assessment of the flexural strength of damaged/repaired plain concrete prisms; slant shear (bond) strength between the concrete and the RM; axial strength of damaged/repaired plain concrete prisms and bond of the repair materials in damaged/repaired reinforced concrete beams loaded to failure. The test results showed that all RMs performed well in restoring the strength of damaged plain concrete. Compatibility of the RMs with substrate concrete was found to be more important in the behavior than superior mechanical properties of the RMs. No difference was noted in the behavior between the RMs in repairing reinforced concrete beams at the tension side. 

scholarly journals Laboratory Assessment of Select Methods of Corrosion Control and Repair in Reinforced Concrete Bridges

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Matthew D. Pritzl ◽  
Habib Tabatabai ◽  
Al Ghorbanpoor
Keyword(s):  
Reinforced Concrete ◽  
Surface Coating ◽  
Concrete Bridges ◽  
Patch Repair ◽  
Chloride Ingress ◽  
Corrosion Control ◽  
Laboratory Assessment ◽  
Accelerated Corrosion ◽  
Deicing Salts ◽  
Patch Repairs

Fourteen reinforced concrete laboratory test specimens were used to evaluate a number of corrosion control (CoC) procedures to prolong the life of patch repairs in corrosion-damaged reinforced concrete. These specimens included layered mixed-in chlorides to represent chloride contamination due to deicing salts. All specimens were exposed to accelerated corrosion testing for three months, subjected to patch repairs with various treatments, and further subjected to additional three months of exposure to accelerated corrosion. The use of thermal sprayed zinc, galvanic embedded anodes, epoxy/polyurethane coating, acrylic coating, and an epoxy patch repair material was evaluated individually or in combination. The specimens were assessed with respect to corrosion currents (estimated mass loss), chloride ingress, surface rust staining, and corrosion of the reinforcing steel observed after dissection. Results indicated that when used in patch repair applications, the embedded galvanic anode with top surface coating, galvanic thermal sprayed zinc, and galvanic thermal sprayed zinc with surface coating were more effective in controlling corrosion than the other treatments tested.

Macrocell Corrosion Formation in Concrete Patch Repairs - A Laboratory Study

2016 ◽  
Vol 711 ◽  
pp. 68-75
Author(s):  
Choorackal A. Eldho ◽  
Ominda Nanayakkara ◽  
Jun Xia ◽  
Stephen W. Jones
Keyword(s):  
Field Application ◽  
Patch Repair ◽  
Steel Bar ◽  
Repair Materials ◽  
Steel Bars ◽  
Patch Repairs ◽  
Macrocell Current ◽  
Macrocell Corrosion ◽  
Chloride Contaminated

Corrosion of reinforcement steel bars is a major threat to the durability of concrete structures exposed to chloride contaminated environment. Patch repairing is widely practiced in affected structures to avoid further damage due to corrosion. Macrocell formation within the patch repair is identified as one main reason for the failure of patch repairs. In the present study, a group of patch repairing materials is tested for their potential to form macrocell corrosion after repaired in a chloride contaminated environment. The influence of parameters such as level of chloride contamination, type of repair materials and the area of steel bar receiving repair are presented based on macrocell current measurements. The selected repair materials for study were cement based, GGBS based and polymer based in its composition. It is found that the severity of macrocell depends on the driving potential existing between the repair and substrate concrete. The quality of substrate concrete and repair material influences the macrocell formation. The surface area of the steel bar that receives the repair also affects the macrocell current. The study will be used for the evaluation of repair materials for macrocell corrosion formation potential before their field application in a chloride contaminated environment.

scholarly journals Proposal of Method Monitoring Macrocell Corrosion Rate at Existing Reinforced Concrete

2008 ◽  
Vol 57 (5) ◽  
pp. 502-508 ◽  
Author(s):  
Yoichi HIRAISHI ◽  
Shinichi MIYAZATO ◽  
Norihiko UMINO ◽  
Kazuo FUJIMOTO
Keyword(s):  
Reinforced Concrete ◽  
Corrosion Rate ◽  
Macrocell Corrosion
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