The Experts below are selected from a list of 9 Experts worldwide ranked by ideXlab platform

N R Buenfeld - One of the best experts on this subject based on the ideXlab platform.

  • protection current distribution in reinforced concrete cathodic protection systems
    Cement & Concrete Composites, 2002
    Co-Authors: A M Hassanein, G K Glass, N R Buenfeld
    Abstract:

    Current distribution from a surface Mounted Anode to steel reinforcement in atmospherically exposed concrete is modelled as a function of the condition of the steel, the resistivity of the concrete and Anode-steel geometry. The boundary conditions at the steel have a significant effect on current distribution with more uniform distribution arising at low steel corrosion rates. In a typical situation the surface of a steel bar facing the Anode may receive 50% more current than the opposite surface. As cathodic protection has proved to be effective in these cases, a basis for many design decisions that influence current distribution is that their effect is small by comparison. When more than one layer of reinforcement is present the current distribution is significantly worse. In this case a surface Anode may not be enough and discrete Anodes may be necessary to improve current distribution. An increase in the concrete resistivity, cover and the Anode to cathode area ratio at a constant Anode current density will increase the voltage drop through the concrete inducing an improvement in the environment at the steel that promotes steel passivity.

A M Hassanein - One of the best experts on this subject based on the ideXlab platform.

  • protection current distribution in reinforced concrete cathodic protection systems
    Cement & Concrete Composites, 2002
    Co-Authors: A M Hassanein, G K Glass, N R Buenfeld
    Abstract:

    Current distribution from a surface Mounted Anode to steel reinforcement in atmospherically exposed concrete is modelled as a function of the condition of the steel, the resistivity of the concrete and Anode-steel geometry. The boundary conditions at the steel have a significant effect on current distribution with more uniform distribution arising at low steel corrosion rates. In a typical situation the surface of a steel bar facing the Anode may receive 50% more current than the opposite surface. As cathodic protection has proved to be effective in these cases, a basis for many design decisions that influence current distribution is that their effect is small by comparison. When more than one layer of reinforcement is present the current distribution is significantly worse. In this case a surface Anode may not be enough and discrete Anodes may be necessary to improve current distribution. An increase in the concrete resistivity, cover and the Anode to cathode area ratio at a constant Anode current density will increase the voltage drop through the concrete inducing an improvement in the environment at the steel that promotes steel passivity.

G K Glass - One of the best experts on this subject based on the ideXlab platform.

  • protection current distribution in reinforced concrete cathodic protection systems
    Cement & Concrete Composites, 2002
    Co-Authors: A M Hassanein, G K Glass, N R Buenfeld
    Abstract:

    Current distribution from a surface Mounted Anode to steel reinforcement in atmospherically exposed concrete is modelled as a function of the condition of the steel, the resistivity of the concrete and Anode-steel geometry. The boundary conditions at the steel have a significant effect on current distribution with more uniform distribution arising at low steel corrosion rates. In a typical situation the surface of a steel bar facing the Anode may receive 50% more current than the opposite surface. As cathodic protection has proved to be effective in these cases, a basis for many design decisions that influence current distribution is that their effect is small by comparison. When more than one layer of reinforcement is present the current distribution is significantly worse. In this case a surface Anode may not be enough and discrete Anodes may be necessary to improve current distribution. An increase in the concrete resistivity, cover and the Anode to cathode area ratio at a constant Anode current density will increase the voltage drop through the concrete inducing an improvement in the environment at the steel that promotes steel passivity.

F Dumat - One of the best experts on this subject based on the ideXlab platform.

  • CORROSION PROTECTION OF THE OUTSIDE STEEL REINFORCEMENT VIA CATHODIC PROTECTION (CP) FROM THE INSIDE OF THE PRESTRESSED HOLLOW BOX-GIRDER OF A MULTI-SPAN CONCRETE BRIDGE
    2003
    Co-Authors: W Schwarz, F Dumat
    Abstract:

    In an extended case study, the applicability of CP applied to the inside walls of the concrete box-girder of a multi-span highway bridge in Hessen, Germany, for the corrosion protection of the steel reinforcement in the outside walls of the box-girder, was evaluated. Results show that the outside steel reinforcement can be protected reliably against corrosion by CP by applying surface Mounted Anode systems on the inside walls of the box-girder. The results show furthermore that the potentials of the prestressed steel cables remain far above the region in which hydrogen embrittlement could occur. The results indicate that significant realkalisation occurs at the outside steel reinforcement, being strongest in carbonated areas. It is concluded that CP applied on the inside walls of concrete box-girders of concrete bridges offers a cost efficient and reliable technique for protecting the outside walls from corrosion induced concrete damage. For the covering abstract see ITRD E123168.

H Audova - One of the best experts on this subject based on the ideXlab platform.

  • CHLORIDE EXTRACTION (CE) FROM CONTAMINATED REINFORCED CONCRETE
    1991
    Co-Authors: G Kirby, P Farinha, A Peek, H Audova
    Abstract:

    Ingress of chloride ions and subsequent reinforcement corrosion is the main deterioration mechanism facing reinforced concrete in marine environments. This paper outlines the theory and practice behind a technique for the removal of chloride ions from concrete structures. The technique involves installation of a temporary surface Mounted Anode encapsulated within a spray-applied fibrous pulp material. An external current source is applied across the reinforcement Anode circuit and the subsequent electrical field draws the chlorides toward the Anode and fibrous electrolyte. At the completion of the treatment the Anode and fiber is removed, taking with it the extracted chlorides. A trial application of the technique is discussed.