What corrosion prevention technologies are available for new concrete structures?
With the increased awareness of cost and serviceability problems associated with concrete deterioration especially for structures exposed to aggressive harsh marine environments, various corrosion prevention measures have been considered and used to improve the corrosion resistance of reinforcements and the durability of concrete structures.
These prevention measures include modifying the concrete mix design, coating to limit chloride or carbonation ingress into the concrete; use of corrosion-resistant reinforcement; addition of inhibitors to the fresh concrete; provision for future electrochemical application in conjunction with corrosion monitoring and cathodic prevention.
Based on studies involving chloride diffusion modelling, carbonation modelling and durability assessment of a number of deterioration mechanisms, it has been suggested that the use of high performance concrete in conjunction with increased concrete cover can provide maintenance-free structures for 50 to 100 years.
While the use of such an approach will lead to a substantial increase in the design life of a structure in a harsh marine environment, findings from these studies are unreliable since there are many other factors that could not be considered in the modelling process. These include concrete cracking; wetting and drying effect in accelerating the rate of chloride penetration; early-age exposure to seawater before the concrete has gained sufficient maturity and density; high temperatures during concrete placement; homogeneity of the concrete and workmanship problems especially in relation to concrete cover. For this reason, it is our opinion that without incorporating additional corrosion prevention measures during construction, it is unlikely that a substantial increase in the service life of structures in harsh marine environment can be achieved.
In many circumstances, incorporating very simple and low-cost measures during the construction process could be very crucial to substantially decrease future maintenance costs.
At Remedial Technology, we have the in house capability and experience to undertake durability assessment for the structure and provide recommendations and cost estimates for various corrosion prevention options.
Our services include:
Durability assessment and corrosion prevention recommendations
Cathodic prevention system installation supervision
Cathodic prevention system monitoring and maintenance