Non-Destructive Testing in Architectural Heritage: A 25-Year Bibliometric Review and Research Trends (2000–2025)

This study presents a systematic bibliometric review of non-destructive testing (NDT) applied to architectural heritage between 2000 and 2025. Unlike previous reviews focused on specific techniques, materials, or applications, it provides a transversal assessment of the field, examining the evolution of diagnostic methodologies, the increasing integration of digital technologies, and the emergence of data-driven approaches within heritage investigation and conservation. A systematic search was conducted in Scopus, Web of Science, ScienceDirect, and JSTOR in November 2025 using predefined NDT- and heritage-related search terms. Peer-reviewed journal articles in English were included, while conference proceedings, theses, and studies unrelated to architectural heritage diagnostics were excluded. Bibliometric indicators, citation metrics, and network analyses were used to evaluate scientific production, thematic evolution, and research impact. A total of 435 studies were reviewed. The results reveal a sustained expansion of NDT research over the last twenty-five years, accompanied by a progressive transition from single-technique investigations towards integrated diagnostic workflows and digitally supported assessment frameworks. In particular, digital and data-driven approaches have become increasingly prominent, highlighting a growing interest in information integration, intelligent monitoring, and predictive heritage management. These findings provide a systematic overview of the evolution of NDT-labeled research in architectural heritage and identify emerging directions that may shape future conservation and diagnostic practices.