TABLE OF CONTENTS H C W U, Wayne State University, USA
A rising crisis facing the world today is its rapidly deteriorating infrastructure. For example, of the more than 600,000 bridges in America, 130,000 are structurally deficient, another 100,000 plus are functionally obsolete, and 143,000 are more than 50 years old and unsuitable for current or projected traffic demands (Zureick et al. 1995). A 1991 study in the United States estimated that transportation agencies could repair or replace only 5,000 of these nonfunctioning bridges annually; however, in the meantime, 6,000 more bridges were added to the deficiency list. The annual cost of maintaining US bridges is over $5.2 billion. Another $8.2 billion per year is needed to eliminate the backlog of bridge construction. Such rapid infrastructure degradation is not unique in the US - it is becoming a global issue. In the United Kingdom, where there are 135,000 bridges, replacement value of damaged bridges is nearly $10 billion and nearly $230 million per year is spent on maintenance (Busel and Lindsay 1997).
The primary cause of decay of America's infrastructure is the deterioration of materials used in the construction and repair of structures. One of the main causes of bridge deterioration is the corrosion of reinforcement steel in concrete decks, exacerbated by road salt used to combat winter ice and snow, especially in the northern US states with their severe weather conditions and heavy use of de-icing salt. In many types of infrastructure, such as concrete bridge decks...
