Developments in microscopy in the last twenty years or so have been dramatic and impressive. Not only can individual atoms be seen with relatively inexpensive instruments, but is even possible to manipulate them, fulfilling the prophecies made by Richard Feyrman in his “Room at the Bottom” address given in 1959. Why, one might reasonably ask. when it is possible to observe, manipulate, and identify single atoms, would someone want to waste their time with an instrument so “old fashioned” as a light microscope?

The need for continued rehabilitation of our concrete infrastructure has lead to the adaptation of modern “state-of-the-art” analytical methods for the characterization of concrete and other cementitious materials. Some of these techniques have not, until relatively recently, been commonly associated with the evaluation of concrete but are very useful both as tools for quality assurance and in the determination of the extent of existing damage. The technique of interest here is the coordinated electron-optical microscopic evaluation of concrete.

Concrete is the most widely used building material in the world. Contrary to popular belief, concrete is not inert but chemically very complex and dynamic. While it is true that, pound for pound, concrete and its raw materials (cement, aggregate and water} are the most inexpensive building materials available for construction, it is also true that it responds to its environment in numerous and sometimes very subtle ways. These responses may sometimes result in a loss of durability and tremendous amounts of time and money being expended while searching for the cause(s) of the problem and providing a cost-effect solution A quick survey of any large metropolitan area and the on-going construction repairs to highways and bridge decks there will quickly confirm this.