Reinforcement corrosion has been widely reported in the literature over the last two to three decades. It is one of the major durability problems, mainly when the concrete is exposed to the chlorides either contributed from the concrete ingredients or penetrated from the surrounding chloride-bearing environment
By cover the concrete to prevent the contact between the concrete and water, as well as you can reduce the conductivity of concrete voids by using tar
1- usage of FRP bars instead of steel bars
2- decrease the permeability by using pozzolanic materials
3- polymer impregnated concrete
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using good quality material and preserve it by impermeable materials
1. protecting the steel with coating material
2. using type 5 cement
3. using dense concrete by using silica fume
4. adding corrosion inhibitor to the concrete
Besides the FRP bars also Epoxy-coated bars are widely used in US. Nowadays combination of High performance concrete and stainless steel starts to be popular.HPC slow down the chloride penetration as well as oxygen penetration thus extendeding the time to onset of corrosion as well slowing down the propagation of corrosion. The stainless steel is significantly less prone to corrosion comparing to conventional reinformcement.
Comment to silica fume (SF). Yes, it slows down the chloride penetration if the concrete is without cracks. However the attention shall be given to shirinkage induced cracking as well. If cracking exists than it leads to much faster penetration of chlorides to the reinforcement level. This concerns the SF mixtures. So the mix design shall be well prepared.
You can find different HPC mix designs and their ability to resist chloride ingress e.g. in
Article Statistical analysis of time dependent variation of diffusio...
You can find the information about the resistance of different steel in the
Article Critical Chloride Corrosion Threshold of Galvanized Reinforcing Bars
There is compared steel reinforcement resisance against chloride induced corrosion. There is comparion of: conventional, glavanized and MMFX (ASTM A1035) steel bars.
Just small notice: Even though galvanized one is better than conventional it is not suitable to be embed in concrete. I am citing from:
Article Problems Connected with use of Hot-dip Galvanized Reinforcem...
The reason is the initial corrosion reaction of zinc coating in fresh concrete producing hydrogen. Further data prove that forming hydrogen irreversibly increases porosity of cement on reinforcement/concrete interface which can significantly reduce bond strength.
The corrosion will very much depend on various salt concentration of water. For example if it is sea,
i. Concrete should have least permeability.
ii. Silica fumes can make the concrete further dense
iii. Addition of pozzolana can improve corrosion resistance.
iv. Polymer imprgnation can further improve
v. if exposed to sulphate salts, C3A content should not be on higher side
Kindly check the link below
https://www.researchgate.net/publication/320020393_BOND_STRENGTH_OF_NANO_SILICA_CONCRETE_SUBJECTED_TO_CORROSIVE_ENVIRONMENTS
Using carbon nano tubes, CNTs, will be the best protection shield for the materials
To minimize the chances of development of corrosion of steel in concrete, the following preventive measures may be taken.
Corrosion protection depends on the level of hazard. Most effective is cathodic protection specially if the environment is very hostile and prone to corrosion. Otherwise one can use following measures
1. Use corrosion resistant bars
2. Corrosion inhibitors are available for making concret
3. Make dense and impermeable concrete so that passivity layer of concrete is not damaged due to ingress of hostile material.
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