A petrographic report is often used in construction disputes or litigation as evidence of poor workmanship by contractors. Contractors may accept these conclusions because they don't understand the limitations of petrographers' techniques. But because of these limitations, some of the conclusions should be challenged.
When reading a petrographic report, you must first separate factual information from conclusions. Note what the petrographer observed, evaluate the accuracy of that observation, and then decide if the observation and the accuracy support the conclusion. Based on the factual observations we've seen in some petrographic reports, conclusions regarding overfinishing, air content, and water-cement ratio were of dubious validity.