REEM SABOUNI
This study was carried out by conducting wet-dry or continuous salt spray tests. Based on the
test results a highly elastic acrylic rubber coating was further tested for long term stability. For
concrete free from chlorides and concrete with up to 1% (of the mortar matrix) sodium chloride
contamination, it was found that the selected rubber coating was able to ensure long term
durability and protect embedded steel by prevent the penetration of air, water and chloride
ions.
3.3 Preventive Techniques Related to the Protection of Reinforcing Steel
3.3.1 Assuring the Quality of Reinforcement Cover:
One simple but very important way of maintaining the protection of the reinforcing steel is
taking good care of the quality of the reinforcing cover. Meaning, having a cover free of
pockmarks and surface blemishes. A good quality cover is achieved by concentrated effort
during placing the concrete in the cover area, good compaction (without trapped air bubbles or
bleed water), high-quality formwork (such as controlled permeability form work) and excellent
curing of the cover zone. Because of harsh climate conditions in the Arabian Gulf curing is of
greater importance [21].
3.3.2 The Use of Inhibitors:
Inhibitors are chemical compounds added to the concrete mix to prevent embedded steel
corrosion and should not have adverse effect on the fresh or hardened properties of the concrete
[22]. The main inhibitors commonly used in the Arabian Gulf are discussed in the following
paragraphs.
3.3.3 Chemical Corrosion Inhibitors
Calcium nitrite is the most commonly used chemical corrosion inhibitors. Nitrites are an inhibitor
that enhances corrosion durability by chemically reacting with the ferrous ions to produce a passive
ferric oxide protective film that blocks active corrosion centers. The effectiveness of inhibitors in
reducing reinforcement corrosion, in the presence of contaminants, such as chloride and sulfate,
was evaluated by measuring corrosion potentials and corrosion current density. Most studies are
based on accelerated test rather than long term [10].
The effectiveness of selected inhibitors in inhibiting reinforcement corrosion in concrete
contaminated with chloride and sulfate salts was studied, and the effectiveness of inhibitors in
reducing reinforcement corrosion, in the presence of contaminants, such as chloride and
sulfate, was evaluated by measuring corrosion potentials and corrosion current density. The
data developed in this study indicate that both calcium nitrite and calcium nitrate were
effective in delaying the initiation of reinforcement corrosion in the concrete specimens made
with sea water, brackish water or unwashed aggregate [10].
Mineral Corrosion Inhibitors
The most commonly used mineral corrosion inhibitors in the Arabian Gulf are: Fly ash, Silica
Fume, and Ground Granulated Blast Furnace. A brief description of each material with its
advantages, and disadvantages in the Arabian Gulf is provided in Table 3.
10
82