scholarly journals Electrochemical behavior of zinc layer anodes used for galvanic protection of steel in reinforced concrete

2018 ◽  
Vol 3 ◽  
pp. 59-65 ◽  
Author(s):  
David Garcia ◽  
Stéphane Laurens ◽  
Stéphane Panin
Keyword(s):  
Reinforced Concrete ◽  
Time Evolution ◽  
Cathodic Protection ◽  
Rapid Evolution ◽  
Steel Corrosion ◽  
Aging Effects ◽  
Protection Systems ◽  
Macrocell Corrosion ◽  
Corrosion System

Steel corrosion is the most common reason for the premature deterioration of reinforced concrete structures. Consequently, cathodic protection of steel in concrete has been substantially developed during the past two decades. In particular, galvanic protection consists in generating a natural macrocell corrosion system in which a sacrificial metallic anode (zinc, typically) is involved to apply a cathodic polarization to the corroding steel layout, in order to mitigate or annihilate the corrosion kinetics. Whether the general principle of cathodic protection is not questionable, the global design process can be significantly improved by increasing the knowledge on electrochemical behaviours of the different components of the protecting system. Regarding zinc anodes in concrete, the literature is very scarce. The time evolution of such systems is also not rigorously addressed, aging effects are systematically ignored and zinc anodes are usually considered as non-polarizable and inert over time. In this paper, the polarization response of a zinc layer anode (ZLA) in concrete electrolyte and its time evolution are studied. The results show a rapid evolution of the ZLA behavior, once the protecting system is connected to steel reinforcements. Moreover, the characterization of ZLA provided relevant electrochemical properties for the numerical design of galvanic protection systems.

Polypropylene Fibre Reinforced Concrete Air Permeability

1990 ◽  
Vol 211 ◽  
Author(s):  
Miguel A. Sanjuan ◽  
A. Moragues ◽  
B. Bacle ◽  
C. Andrade
Keyword(s):  
Carbon Dioxide ◽  
Reinforced Concrete ◽  
Steel Corrosion ◽  
Air Permeability ◽  
Polypropylene Fibre ◽  
Fibre Reinforced Concrete ◽  
Polypropylene Fibres ◽  
Cement Ratio ◽  
Reinforcing Steel Corrosion

AbstractThe permeability of concrete to gases is of direct importance to the durability of concrete structures, because of carbon dioxide flowing through the concrete favour lime carbonation and reinforcing steel corrosion.Mortar with and without polypropylene fibres having water/cementitious ratios of 0.30, 0.35 and 0.40 and a cement/sand ratio of 1/1 were studied. Polypropylene dosage varied from 0.1 to 0.3% by volume of cement.The characterization of mortar permeability was made using cylindrical shaped samples (3 cm height and 15 cm diameter). These specimens were 28 days cured and then dried before the test.The addition of fibres results in a decrease of air permeability. Variation of the water/cement ratio is of lesser importance than fiber addition.

Long-term aging effects on tensile characterization of steel fibre reinforced concrete

2016 ◽  
Vol 17 (6) ◽  
pp. 1082-1093 ◽  
Author(s):  
Thomaz Eduardo Teixeira Buttignol ◽  
Matteo Colombo ◽  
Marco di Prisco
Keyword(s):  
Reinforced Concrete ◽  
Steel Fibre ◽  
Fibre Reinforced Concrete ◽  
Aging Effects ◽  
Steel Fibre Reinforced Concrete ◽  
Tensile Characterization

Characterization of Thermal-Sprayed Titanium Anodes for Cathodic Protection

1997 ◽  
Author(s):  
G.R. Holcomb ◽  
S.D. Cramer ◽  
S.J. Bullard ◽  
B.S. Covino ◽  
W.K. Collins ◽  
...  
Keyword(s):  
Cathodic Protection ◽  
Thermal Spraying ◽  
Atmospheric Gases ◽  
Steel Reinforced Concrete ◽  
Protection Systems ◽  
Titanium Coatings ◽  
Impressed Current ◽  
Impressed Current Cathodic Protection ◽  
Lower Resistivity

Abstract Thermal-sprayed titanium coatings were investigated as anodes for impressed current cathodic protection systems for steel reinforced concrete structures. The coatings were applied by twin-wire thermal-spraying using air and nitrogen as atomizing gases. The coatings were non-homogeneous due to oxidation and nitridation of the molten titanium with the atmospheric gases oxygen and nitrogen. The primary coating constituents were α-Ti (containing interstitial nitrogen and oxygen), γ-TiO and TiN. Nitrogen atomization produced coatings with less cracking, more uniform chemistry, and lower resistivity than air atomization.

scholarly journals The Performance of Carbon Fibre Composites as ICCP Anodes for Reinforced Concrete Structures

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Chinh Van Nguyen ◽  
Paul Lambert ◽  
Pal Mangat ◽  
Fin O’Flaherty ◽  
Graeme Jones
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fibre ◽  
Cathodic Protection ◽  
Concrete Structures ◽  
Steel Corrosion ◽  
Concrete Surface ◽  
Reinforced Concrete Structures ◽  
Reinforcing Steel ◽  
Fibre Composites ◽  
Carbon Fibre Composites

Cathodic protection has been proven to be one of the most widely applicable and cost-effective solutions for tackling steel corrosion in reinforced concrete. In this study, the possible use of carbon fibre composites, which are primarily used to strengthen concrete members, has been investigated as impressed current cathodic protection anodes. Carbon fibre anodes have been assessed in both concrete and calcium hydroxide solution. Two bonding mediums incorporating epoxy and geopolymer have also been investigated. The results demonstrate that epoxy resin can be used for bonding carbon fibre fabric anodes to reinforced concrete structures while geopolymer is more effective for bonding carbon fibre reinforced polymer (CFRP) rod into preformed grooves in the concrete surface. The dissolution of carbon fibre anode appears to stablise after a period of time, dependent upon the size and shape of the anode and applied voltage and current. Based on the present results, a maximum current density of 128 mA/m2 of reinforcing steel area is recommended for the operation of CFRP fabric anode and 64 mA/m2 of reinforcing steel area for that of CFRP rod anode.

scholarly journals Cathodic protection in reinforced concrete structures affected by macrocell corrosion: a discussion about the significance of the protection criteria

2017 ◽  
Vol 2 ◽  
pp. 27-32 ◽  
Author(s):  
Stephane Laurens ◽  
Raoul Francois
Keyword(s):  
Reinforced Concrete ◽  
Cathodic Protection ◽  
Concrete Structure ◽  
Polarization Current ◽  
Reinforced Concrete Structure ◽  
Concrete Wall ◽  
Depolarization Current ◽  
Impressed Current ◽  
Macrocell Corrosion ◽  
Control Corrosion

Cathodic protection is a technique that has been used to control corrosion and increase the service life of reinforced concrete structure. Standards as EN ISO 12696 give protection criteria for both impressed current and sacrificial anodes techniques, based on potential value or decay during a depolarization sequence. The polarization (current ON) and depolarization (current OFF) is experimentally studied on a corroded concrete wall thanks to six references electrodes and compared to a time-dependent modelling using FEM software COMSOL Multiphysics. Both experimental and numerical results show significant differences in the time response according to electrode location. This conclusion indicates that the concept of protection criteria defined by the standards is not suitable to assess the efficiency of cathodic protection applied to reinforced concrete structure.

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