Introduction

The degradation of steel reinforced concrete (RC) structures is a critical issue of worldwide concern, due to high maintenance requirements and resulting in shorter service lives of concrete facilities. In the United States, the average age of the approximately 600,000 bridges in the interstate highway system is 45 years old. About one-fifth of those bridges are classified as structurally or functionally deficient. It is estimated that the repair cost for existing highway bridges is more than $50 billion, and $1-3 trillion for all concrete structures. In Canada, about 40% of bridges above 40 years of life and numerous multistory parking garages are structurally deficient. The cost of repair of parking garages alone in Canada is estimated at more than $6 billion and over $74 billion for all concrete structures. In Europe, the estimated annual cost of concrete repair is about £1 billion (Balendran and Leung 2003, Nkurunziza et al. 2005).