Familiarity with the concept and application of acoustic methods as a non-destructive method in the study and recognition of architectural heritage

To take any action to protect a historic building, awareness of the mechanical properties of the materials and their constituent elements is a necessary step that must be accompanied by the minimal damage to the body and texture of the historic building. Minimizing interventions in the historical structure and using non-destructive methods to study and identify its elements is one of the requirements for improving the status of cultural heritage. Among non-destructive methods, acoustic techniques are one of the most commonly used methods in recent decades, which provide us with critical information about the quality and protective status of the elements under study. The purpose of this study is to investigate the performance, capacity, and results of using acoustic wave propagation to analyze the conservation status of heritage buildings. This article is a review of scientific researches from the last six years in the field of studies and research related to acoustic tests and a summary of the basic technical principles, equipment required, how to perform tests, applications, limitations in relationship with the conditions of the site and finally the analysis of the data obtained from these tests. Studies show that different materials and structures, as well as damages such as cracks and internal cavities, behave differently against the propagation of acoustic waves. As a result, the same difference in behavior can be used to assess the quality of buildings and materials, identify existing heterogeneities, injuries, especially cracks, detachment of wall coatings, and control the effectiveness of therapeutic measures.