Q.: We've recently undertaken a few crack repair jobs and have become acquainted with a variety of methods including epoxy injection, routing out and resealing, and using overlays. Now we're thinking of going more into the business but would like to be sure we understand the best approaches for various situations. Looking over some of the literature, we find the number of approaches bewildering. Has anyone done a systematic study of the many methods available and published a comparison?

A.: In the May-June 1984 issue of the ACI Journal, beginning on page 211, there is a 20-page report by ACI Committee 224 called "Causes, Evaluation, and Repair of Cracks in Concrete Structures" that covers the subject well. The same report can be found in the ACI Manual of Concrete Practice, 1986, Part 3. A condensed version of about 5 pages, which doesn't include the information on causes of cracking or evaluation of their condition, was published in Concrete Construction in January 1985, page 37, under the title "How to Fix Cracks." These articles give a pretty good overview of the subject.