The demand for maintenance and repair of concrete structures in service has been critically increasing worldwide. A variety of techniques and evaluation methods for diagnosis and prognosis of the structures are extensively under development by applying nondestructive evaluation (NDE). As inspection techniques, a major issue is on-site measurement. Thus, acoustic emission (AE) techniques draw great attention to the practices in concrete structures. With respect to AE measurements in concrete, three RILEM recommendations have been published, and are known to be readily available for practical applications.In order to extend the service life of concrete structures, we have proposed the establishment of “infra-dock”, which is named as an inspection system for the prognosis, as referring to the ship dry-dock. Consequently, in relation with establishment of the infra-dock, prospective applications of AE techniques are updated and reviewed on the basis of AE measurements developed. Successful results on prognosis of the fatigue damage in a pre-stressed concrete bridge, the earthquake attack to a concrete aqueduct, nucleation process and mechanisms of corrosion-induced cracks in reinforced concrete are summarized and discussed.