IMPACT-ECHO NON-DESTRUCTIVE TESTING OF CONCRETE

There is a growing need for repair of concrete structures in Denmark, and therefore a need for assessing the condition of the concrete and the expected development of damage as a basis for the choice of maintenance and repair strategy. The need for new methods of investigation has grown with the increasing amount of repair work. The Impact-Echo method is a non-destructive method for investigating concrete structures. It is based on the relation between the time taken for a wave to traverse a given distance and its velocity. By using the Impact-Echo method, hidden damage in a concrete section (delamination, honeycombing, etc.) can be detected. The purpose of the present investigation is to determine whether the method can be used for the assessment of: - Damage caused by alkali-silica reactions and freeze-thaw cycles. - The condition of a waterproofed bridge deck. The starting point was to use the method on structures that had previously been investigated and described in detail using other methods of investigation. (A)