Abstract
This paper presents a methodological study on tracing the material composition and construction technology of historical concrete. Samples were taken from a beam in the basement of the University Road Building of the Zhejiang Library, a Chinese national heritage building. This study measured the apparent density and gas permeability coefficient of the concrete samples. They were then mechanically disintegrated to extract the hardened cement paste, which, after crushing, was analysed by XRD to determine its composition and proportions. Besides, other concrete samples were dissolved in dilute hydrochloric acid, followed by solid-liquid separation, to calculate the cement content. The remaining aggregates were subsequently classified by their characteristics. Mercury intrusion porosimetry was employed to analyse the pore structure of the microstructure, while SEM was used to examine the interfacial transition zone. And results indicated that this historical concrete had poor durability, which can be attributed to uneven aggregate size distribution, increased porosity, relatively low cement content, and insufficient compaction resulting from the construction technology employed. In conclusion, this study presents a methodology of tracing historical concrete information, offering a practical and effective tool for the research and preservation of historical concrete.