Modern acoustic techniques for testing concrete structures accessible from one side only

This paper presents nondestructive methodologies for investigating selected geometrical and material imperfections in unilaterally accessible concrete structures by means of modern acoustic techniques. The imperfections include: improper structure thickness, delamination, large air voids and zones of concrete macroheterogeneities. The presentation of the methodologies is preceded by a survey of the literature on the subject. The available knowledge, also contributed by the present author, has been collected and systematized as well as complemented with two new methodologies for determining the depth of cracks. The methodologies have been validated in situ on building structures whereby their practical usefulness has been confirmed.