Q. As we are more and more concerned with durability, how do we measure it on a given structure after a year or after 5 years?

A. If you are thinking about both surface condition and structural integrity you should consult the ACI 201 Standard, "Guide for Making a Condition Survey of Concrete in Service," which appears in Part I of the ACI Manual of Concrete Practice.

Illustrations from that report are reprinted in a series of articles in Concrete Construction magazine, "Surveying Concrete in Service," June 1969, August 1969, and September 1969 pages 347 and 349 to 352.

Nondestructive testing and petrographic examination can be run, if necessary, by some of the agencies listed in the professional services section on the next to the last page of current issues of Concrete Construction.