Experimental Investigation of the Behaviour of Reinforced Concrete Structures Exposed to the Escravos River of Nigeria

Abstract

This study investigated the behaviour of reinforced concrete
structures exposed to the Escravos River of Nigeria. Reinforced
concrete samples were prepared in the laboratory with various sizes
of steel reinforcement – 10mm, 12mm and 16mm diameter steel bars.
After curing, these samples were immersed into water samples
extracted from the Escravos River. The corrosion process was
accelerated by means of application of an external impressed current
of 0.4A. The impressed current was applied via a 12 volts DC power
source. The circuit was connected in such a way that the protruding
steel reinforcement served as the anode, while a 6mm stainless steel
rod that was placed in the solution/electrolyte served as the cathode.
Various tests were carried out to determine the corrosion current,
corrosion resistance and the chloride diffusion coefficient of the
concrete. The results obtained showed that the size of the embedded
steel reinforcement influences the corrosion behaviour of the
structure. As the size of the steel reinforcement increased, the
corrosion current increased while the corrosion resistance
decreased. This was attributed to the larger surface area of the larger
diameter steel reinforcements. On the other hand, varying the size of
the steel reinforcement did not have any impact on the rate of
chloride diffusion into the concrete samples.