The most commonly recognized causes of de-passivation of reinforcing steel in concrete structures in
industrial environments are chloride penetration and loss of alkalinity due to carbonization, but in
addition stray current may be a cause of localized accelerated corrosion. In several cases including
roadwork structures, bridges, retaining walls and marine structures, cathodic protection has proven to
be an effective means to control corrosion. Cathodic protection of reinforcement bars in concrete may
be provided by sacrificial, impressed current, or combined systems. The performance of a CP system
will be critically affected by the level of contamination with chlorides- which affects both the
conductivity of the concrete and the potentials required to provide protection. Performance of a system
will also be critically affected by stray currents from nearby power supplies, which in the worst case
can promote corrosion. However, the design of effective CP systems in new builds or retrofits is
sometimes difficult to achieve due to lack of practical experience and the sometimes significant
complexity of the structure design and access. In this field, computational modeling can provide
important information on the effectiveness and feasibility of corrosion control solutions.
The aim of this paper is to present a modeling approach for cathodic protection systems applied to
steel reinforced concrete structures. The approach uses boundary element techniques, which firstly
allow simplified representation of the effects of contamination by using a layered representation of the
concrete, and which secondly allow simplified determination of the effects of possible stray current
from nearby power sources.
Keywords: Simulation, mathematical modeling, CP, stray current, rebar, concrete