THE IMPACT-ECHO RESPONSE OF CONCRETE PLATES CONTAINING DELAMINATIONS - NUMERICAL, EXPERIMENTAL AND FIELD STUDIES

This paper describes the use of the impact-echo technique - a non-destructive testing technique based on the use of transient stress waves - for detecting delaminations in concrete plate-like structures such as bridge decks, slabs, and walls. Results obtained from numerical (finite element) analysis and controlled-flaw laboratory studies are presented and used to explain the elastic impact response of delaminated plates. Current impact-echo instrumentation is described, and results obtained from concrete bridge decks containing delaminations caused by corrosion of reinforcing steel are presented. These results provide a better understanding of the impact response of delaminated plates.