A research committee on corrosion evaluation and protection technology of reinforcing steel
in concrete (338 Committee) was established in September 2007 as one of the subcommittee of Concrete Committee of Japan
Society of Civil Engineers.
In the Committee, the following research works were carried out by
three working groups (WG);
- to establish a framework of durability verification method for concrete
structures deteriorated by chloride attack (undertaken by WG1) ,
- to clarify inspection and monitoring methods for corrosion of reinforcing
steel (here-in after called "rebar") in concrete (undertaken by WG2),
- to
evaluate protection and repair systems for deterioration due to rebar corrosion
and their quantitative performance evaluation method (undertaken by WG3).
The committee activities during the first term (2007-2009) yielded the following results:
- Summarized the information effective for establishing a durability verification
method of concrete structures, such as study results related to corrosion
initiation on rebar in concrete and corrosion crack initiation on concrete.
Furthermore, proposed a future strategy of durability verification system
for concrete structures in a chloride environment (See Figure 1).
-
Examined a prediction method for the deterioration process of existing structure in chloride environment during maintenance activities
based on the latest information on nondestructive methods and monitoring systems for corrosion of rebar in concrete (See Figure 2).
Further, a new technology of nondestructive prediction method related to chloride concentration on concrete surface was also discussed.
-
Focussing on five repair methods for deterioration due to chloride attack, such as surface treatment methods, concrete section replacement
methods, cathodic protection methods, desalination methods and FRP bonding method, not only the newest research data but also information
on blunder examples on each method were collected and analyzed. Based on the information, the most suitable repair method for concrete
structures deteriorated due to chloride attack was selected and discussed (See Figure 3)
These research works and obtained results were summarized as a committee report titled “Concrete engineering series 86: State of the art
report on corrosion evaluation and protection technology of reinforcing steel in concrete” published in October 2009.
The second term (2010-2011) activities in the committee have started from this March to establish the newest concepts on durability
design and, maintenance and repair method for concrete structures in chloride environment.
|
Figure 1 Concept of performance verification of concrete structures deteriorated by chloride attack
Figure 2 Concept of prediction method during maintenance activity for the deterioration process of existing structure in chloride environment
|
