Title:
Durability of Reinforced Concrete Caisson Parapet Beam Exposed to Mediterranean Seawater after 500 Days
Author(s):
Igor Lapiro, Rami Eid, and Konstantin Kovler
Publication:
Materials Journal
Volume:
121
Issue:
1
Appears on pages(s):
41-54
Keywords:
corrosion; durability; galvanized steel; glass fiber-reinforced bars (GFRP) bars; inhibitor; marine structures
DOI:
10.14359/51740260
Date:
1/1/2024
Abstract:
The penetration of chloride ions causes degradation of reinforcing
bars, which directly affects the service life of the element. In this
study, four different alternatives for the construction of a reinforced
concrete (RC) caisson parapet beam are investigated: conventional
RC, the addition of a corrosion inhibitor to concrete, and the use
of glass fiber-reinforced bars (GFRP) and galvanized steel instead
of steel bars. The durability of the RC element under marine environment was studied based on measurements performed both
in-place and in well-controlled laboratory conditions on specimens
prepared in the laboratory, as well as specimens taken from the
actual structural element. It was concluded that the exposure of fresh concrete to seawater splash has no effect on mechanical properties. In addition, galvanized rods were found to be a less effective protection strategy compared to the other alternatives studied. GFRP bars, however, provide better protection than the other tested alternatives, although chloride ion penetration in these bars was found to be more accelerated in an alkaline environment compared to a chloride environment. In contrast to the prevailing approach, which considers plain concrete and according to which the electrical resistance of the concrete decreases because of chloride penetration, this study found that electrical resistance in the reinforced element is increased due to an increase in the amount of corrosion products formed between steel and concrete if no cracks occur. Furthermore, it was found that the potential measured using
the half-cell method in all the alternatives slowly increased with
time, as well as the corrosion risk in the three alternatives with
reinforcing steel. The remaining question is whether this change of
potential is a direct characteristic of the corrosion risk. Therefore,
more research in this direction is needed.