Applicaton of impact echo in long term condition monitoring of concrete bridge decks - A numerical study

The application of the Impact Echo (IE) test in long term condition monitoring of concrete bridge decks was investigated through a comprehensive numerical study. The potential use of the IE technique for detection of various stages of delamination progression was evaluated. It was assumed that the condition of a delaminated deck worsens according to two probable scenarios. The first scenario assumes the growth of a single small delamination. The second one involves progressive expansion of a number of small delaminations and their ultimate linking to make a large delaminated area. Both deterioration scenarios were numerically simulated by analyzing a large number of finite elements (FE) models of concrete decks containing expanding delaminations (Scenario 1) and delamination segments of increasing size (Scenario 2). Changes in the IE test results due to the expansion of a delaminated zone according to either scenario were studied. The numerical results indicate that the worsening condition of the deck has distinct effects on the IE test results which can be easily identified. Therefore, IE test can be employed for condition monitoring of concrete bridge decks.