Innovative Techniques for Extending the Service Life of Deteriorating Concrete Piers and Wharves

There exists no code or cookbook formula to assist the design engineer in implementing effective rehabilitation measures on waterfront facilities. Examples of repairs that have failed prematurely abound in this field. Rehabilitation schemes that address the underlying root cause or causes of deterioration are, unfortunately, the exception to the rule. Rehabilitation measures that simply patch existing defects often do a disservice to the owners of these facilities. Effective rehabilitation strategies must go beyond the repair of existing defects by protecting the remaining unrepaired structure from premature or accelerated degradation. Service life extension involves the quantitative modeling of protection strategies in order to determine the most cost-effective method or combination of methods to preserve the structural integrity of the facility for a specified period of time. The concrete repair and protection industry is enormous, attracting considerable attention from vendors seeking to solve problems and provide solutions to owners and engineers. The volume of products available can be daunting for the design engineer to sort out and, despite the barriers to acceptance in the marketplace, the list grows longer every year. As can be expected, not all of the available products and solutions are effective and it is incumbent upon the design engineer to sort through what works and what does not. Several outstanding techniques have emerged in recent years that deserve special recognition. This paper highlights several recent developments in service life prediction modeling and repair techniques such as incorporating cathodic protection in innovative ways such as embedded anodes, metallized coatings, and pile jacketing. There are even ways of removing chloride ions from contaminated concrete while repassivating the embedded reinforcing steel. Each of these techniques will be discussed and evaluated in this paper. A case study highlighting an effective service life extension evaluation at the Port of Portland is also presented.